Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: hurodal on July 09, 2019, 08:07:33 am
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Hello all,
My name is Hugo and I work as a color management professor, technician and consultant at Barcelona, Spain.
I want to introduce you a new color chart I've been slowly working on for the last 4 years. I've been making wide gamut IT8 since 2006 and one of my main interests is achieving a true high fildelity in captures, specially for those areas where highly saturated/difficult colors sometimes appear: commercials, art reproduction and, specially, cloth wear e-commerce.
I designed this chart using my experience making IT8s, taking some ideas frrm other charts and adding new ideas of my own. This is a color chart aimed to produce the very best camera profiling out there, with no compromise.
It's not as easy to use as a matte chart (CC classic, spyderchecker) but with it's 999 color patches it offers really high precision. I've been working with it and at the same time testing it in some really hard scenarios like some of the biggest cloth brands here in Spain: ZARA, Mango, Tendam, Desigual, as well as in the National spanish Biblioteque and other institutions. The results have been impressive so far.
You can see all the information about it here:
HR-1 SuperChroma (https://www.hugorodriguez.com/blog/hr-1-superchroma-eng/)
I'd love to share and discuss technical details and the like with anyone interested here. I hope you find it interesting.
(http://)
Best regards,
Hugo
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Sorry, but you can predict in advance that this is actually a bad idea, which is proved by the samples that you providied.
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Hi Czornyj,
I wasn't expecting warm compliments in the very first replies but at least some curiosity and questions about the chart, rather than negativity and rejection.
OK, let me know what you already predicted and concluded just by looking at the samples (I guess you also got the reference spectral file and did some calculations and research...).
Regards,
Hugo
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You can see all the information about it here:
HR-1 SuperChroma (https://www.hugorodriguez.com/blog/hr-1-superchroma-eng/)
I'd love to share and discuss technical details and the like with anyone interested here. I hope you find it interesting.
So can you explain what the before's ("Standard: without profile") implies?
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Hard to judge just by looking at your photos of your actual target, but it looks as if you are generating the color patches the same way IT8 targets are made.
If so, then that's a deal breaker. The color patches would be made of dyes generated by wet process (RA-4) chemistry. The cyan, magenta, yellow layers are stacked in three layers to form the colors, and there will be lots of color constancy (metameric mismatches) between how the camera records those colors and how the camera records real world spectra. A camera target is a different application all together from the use of IT8 targets to profile scanners for scanning film or color prints. IT8 targets are "training" the scanner to look at the very same dyes which will be scanned during the reproduction, i.e., either wet process color prints or color transparency films. It's why a different IT8 target is ideally required for every film type, definitely Kodachrome versus EktaChrome, because the color dyes are so spectrally different between those two film types.
The 24 patch Macbeth color checker chart uses specially formulated color pigments designed to precisely mimic real world color spectra (e.g., skin tones, blue skies, green foliage, etc), and this technical achievement by C.S. McCamy, et al, back in 1976 is a critical reason why the Macbeth Colorchecker chart functions as well as it does for digital camera profiling in the digital age.
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Great history of the MacBeth found here:
http://www.babelcolor.com/colorchecker.htm
I agree with Mark about potential issues using a process built for profiling scanners with cameras.
One issue with the MacBeth is only one path falls outside sRGB (Cyan). So we shouldn't expect the gamut of the resulting profile to be any larger but gamut and cameras are problematic for oh so many reasons.
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Great history of the MacBeth found here:
http://www.babelcolor.com/colorchecker.htm
I agree with Mark about potential issues using a process built for profiling scanners with cameras.
One issue with the MacBeth is only one path falls outside sRGB (Cyan). So we shouldn't expect the gamut of the resulting profile to be any larger but gamut and cameras are problematic for oh so many reasons.
I'm no expert in camera profiling (and don't use it much, if truth be told), but my understanding is that the camera profiling programs are using the 24 Macbeth patches to help scale the RGB channels. They aren't clipping nor are they constrained to those values by any means. It would be an epic fail if they did. So, some interpolation and extrapolation is happening in the profiling app to scale colors different than the 24 chosen patches and also with higher chroma than those 24 patches. The camera primaries are also generally well known, so as long as the result generates a good match when photographing the ColorChecker, other interpolate and/or extrapolated values should be more accurately reproduced as well. Maybe not perfect but better than nothing.
I prefer to season all of my color work to taste from the RAW files. I use Adobe ACR, and find the built in camera calibration flavors are often just as suitable a starting point for my work as the custom camera profiles I have made with apps like ColorChecker Passport, etc.
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The 24 patch target is just fine to build .DCP profiles which are vastly different than ICC profiles especially with respect to how and where in the processing chain the operation. For ICC camera profiles, it's similar to making a scanner profiles as you outlined. It's 'finger-printing' as best it can, the rendered (output referred) image. So along with too few color patches and a limited target color gamut, GMB (now X-rite) produced two actual 'camera' profile targets. The SG had a wider gamut using glossy patches but it was a bitch and a half to shoot (no reflections please). Then they came up with a newer target without the glossy patches but smaller color gamut. Frankly I found camera profiling for the creation of ICC profiles hugely hit or miss. Gave up on em. And since my raw processor of choice doesn't even allow the use of ICC camera profiles, even better. In very controlled studio like conditions (think copy work), I was able to produce good ICC camera profiles. But shoot outside that condition, not so much.
Since at least you and I use an Adobe raw processor, a custom .DCP profile with the Macbeth gets the job done nicely. KISS. ;) [size=78%] [/size]
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So can you explain what the before's ("Standard: without profile") implies?
Hi,
Yes, it means with the generic profile (Capture one's profile in this case).
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Hi,
Yes, it means with the generic profile (Capture one's profile in this case).
Begs the question, how would the 'before's' look with another raw converter?
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Hi Hugo,
Good stuff, I'll probably be a customer. I am curious on how you chose those specific patches and the kind of improvement you would expect from using this hi-res chart vs a lower resolution one like the CC24. Where would you expect the most improvements? Are there any comparisons of its performance vs CC24 once profiled, on standard targets representative of specific situations (like landscape, portraits etc.) all other things being equal?
Thanks!
Jack
PS I kind of agree with others that the before and after images look kind of hokey and are not going to pass muster here: were those done by your marketing department? ;)
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Hard to judge just by looking at your photos of your actual target, but it looks as if you are generating the color patches the same way IT8 targets are made.
If so, then that's a deal breaker. The color patches would be made of dyes generated by wet process (RA-4) chemistry. The cyan, magenta, yellow layers are stacked in three layers to form the colors, and there will be lots of color constancy (metameric mismatches) between how the camera records those colors and how the camera records real world spectra. A camera target is a different application all together from the use of IT8 targets to profile scanners for scanning film or color prints. IT8 targets are "training" the scanner to look at the very same dyes which will be scanned during the reproduction, i.e., either wet process color prints or color transparency films. It's why a different IT8 target is ideally required for every film type, definitely Kodachrome versus EktaChrome, because the color dyes are so spectrally different between those two film types.
The 24 patch Macbeth color checker chart uses specially formulated color pigments designed to precisely mimic real world color spectra (e.g., skin tones, blue skies, green foliage, etc), and this technical achievement by C.S. McCamy, et al, back in 1976 is a critical reason why the Macbeth Colorchecker chart functions as well as it does for digital camera profiling in the digital age.
The chart is printed in an Epson inkjet plotter, not by chemical process. Chemical process is being removed everywhere. For printing color charts, chemical process presents many variables and it's hard to keep constancy. Inkjet is much more adequate, and it offers a wide gamut.
There's not a big difference between how the spectra is mixed in a chemical paper and inkjet print, because in chemical, dyes are layed one over another, while in an inkjet, pigments are placed one beside another.
I've read many times about the argument that the spectra of the real world vs the pigments but for this chart is not an issue, because:
- It's aimed for art reproduction, which uses systhetic pigments, just like inkjet.
- it's aimed for product photography, which (except food) is always printed used synthetic pigments. Cloths, packaging... all use these pigments.
But, anyway, I've tested in real world, landscape and it gives extraordinary results. Ornitologhists, i.e. had told me that photos profiled with the Superchrome are the best they've seen, ever. And birds use natural pigments, of course.
Regarding the CC classic, I know it very well; In fact I have 5-6 in almost all versions.
I've read babelcolor site and I'm also in contact with Danny pascale, the man behind Babelcolor. In fact, he helped me in some stages of the development.
Yes, Macbeth developed pigments that are similar to the real world, back in 1976, which is more than 40 years ago. Since then, there's a company in Japan that had invested zillions of Yens to improve their pigment formulation: Seiko-Epson.
Don't you think that with the money they invested in research (which I guess we all agree that is WAY more than what Macbeth invested 40 yrs ago) they achieved extraordinary pigments with excellent spectra nowadays?
the main problem with CC is that it only has 24 different patches (actually only 18 in color). I've used it for camera profiling and while with skin and some low saturation color works well, with highly saturated or difficult colors, the results are far from perfect.
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Great history of the MacBeth found here:
http://www.babelcolor.com/colorchecker.htm
I agree with Mark about potential issues using a process built for profiling scanners with cameras.
One issue with the MacBeth is only one path falls outside sRGB (Cyan). So we shouldn't expect the gamut of the resulting profile to be any larger but gamut and cameras are problematic for oh so many reasons.
Thanks for the link. I already knew that article.
Well, a limited gamut chart can actually build wider gamut profiles for linear capture devices. The problem is that cameras are not that linear, and there's also another problem: the interpolation between primaries is actually very complicated if the chart has not high resolution.
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Begs the question, how would the 'before's' look with another raw converter?
Quite different, actually. That's one of the main differences of the several raw converters. ACR, i.e., IMHO renders dirt colors, just by opening the file with no setting at all.
Capture one shines on that: in the same scenario, the colors are quite cleaner.
Not to mention how bad is ACR color engine when you use the sliders of HSL or calibration tab, which causes a lot of strange artifacts and posterization, something that never happens with Capture One.
Thus I only recommend Capture One for the purposes that chart is aimed to.
Please take a look at this photo I've taken, developed with ACR and C1. Both with no special settings, other than a small under exposure. Both with generic profiles (provided by Adobe/Phase one)
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The chart is printed in an Epson inkjet plotter, not by chemical process. Chemical process is being removed everywhere. For printing color charts, chemical process presents many variables and it's hard to keep constancy. Inkjet is much more adequate, and it offers a wide gamut.
There's not a big difference between how the spectra is mixed in a chemical paper and inkjet print, because in chemical, dyes are layed one over another, while in an inkjet, pigments are placed one beside another.
I've read many times about the argument that the spectra of the real world vs the pigments but for this chart is not an issue, because:
- It's aimed for art reproduction, which uses systhetic pigments, just like inkjet.
- it's aimed for product photography, which (except food) is always printed used synthetic pigments. Cloths, packaging... all use these pigments.
But, anyway, I've tested in real world, landscape and it gives extraordinary results. Ornitologhists, i.e. had told me that photos profiled with the Superchrome are the best they've seen, ever. And birds use natural pigments, of course.
Regarding the CC classic, I know it very well; In fact I have 5-6 in almost all versions.
I've read babelcolor site and I'm also in contact with Danny pascale, the man behind Babelcolor. In fact, he helped me in some stages of the development.
Yes, Macbeth developed pigments that are similar to the real world, back in 1976, which is more than 40 years ago. Since then, there's a company in Japan that had invested zillions of Yens to improve their pigment formulation: Seiko-Epson.
Don't you think that with the money they invested in research (which I guess we all agree that is WAY more than what Macbeth invested 40 yrs ago) they achieved extraordinary pigments with excellent spectra nowadays?
the main problem with CC is that it only has 24 different patches (actually only 18 in color). I've used it for camera profiling and while with skin and some low saturation color works well, with highly saturated or difficult colors, the results are far from perfect.
I can easily debate some of the conclusions you have drawn and stated above, but I won't. Good luck with your project. I'm happy you are happy :)
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Hi Hugo,
Good stuff, I'll probably be a customer. I am curious on how you chose those specific patches and the kind of improvement you would expect from using this hi-res chart vs a lower resolution one like the CC24. Where would you expect the most improvements? Are there any comparisons of its performance vs CC24 once profiled, on standard targets representative of specific situations (like landscape, portraits etc.) all other things being equal?
Thanks!
Jack
PS I kind of agree with others that the before and after images look kind of hokey and are not going to pass muster here: were those done by your marketing department? ;)
Thanks Jack!
The approach I've taken for this chart is quite different than any other chart in the market. Most charts uses gradients. They put gradients for colors, going from black/white/grey to the most saturated color. This looks good at first glance, but it causes poor distribution in three areas:
- near black
- near white
- between gradients
The superchroma uses perceptually evenly distributed patches that doesn't follow gradients. this means that there's the same amount of patches almost everywhere inside the gamut -> constant quality through the entire gamut.
Other charts provide good quality near/around the gradients of patches but poor (or very poor) quality far from (or between) them.
Yes, I have lots of examples that I'm preparing for an article to be published here in the main website, with the kind help ot Kevin, main editor of this site.
The biggest improvement I've seen so far was with a turquoise color of a women bag, made with colombian wood. A pro photographer that was doing a job for the customer was in big problems because even doing a good profile with CC24 in ACR the result was way off the path, because it was rendered as blue.
With my wide-gamut IT8 and Capture One it was rendered as green, much closer, although not yet perfect. This photo was the reason I've started to design this new chart.
Please look at the attached examples. One (the blueish one) is the generic profile in ACR. Another is also from ACR but with the custom profile with CC 24. I also attach the color sample of the wood for reference.
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I can easily debate some of the conclusions you have drawn and stated above, but I won't. Good luck with your project. I'm happy you are happy :)
I'm open to discussion, sir, as long as you talk with respect as I do. As you wish :-)
As we're discussing with our own opinion, let me show some data, that is out of discussion.
You've mentioned blues and greens. Well, I've searched for the closest blue and green to the primaries on the CC24. There are no exact colors that match in the Superchroma but these two are the closest. Beside you can see the spectra information for both samples.
It has to be taken in count that the ones in the HR1 are actually mixed inkjet primaries, but as you can see the spectra curves are both very smooth and look so close to the other.
I don't think metamerism is an issue here.
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Interesting product. Thanks for posting.
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Couple points:
1. This comment about linear or non linear is moot. ICC profiles take place on rendered data that might be either, NOT the raw data.
2. There is no such thing as ‘no setting’ in ACR/LR. You might not like the defaults (dirt rendering?) but they can easily be changed and since these products CANNOT use ICC camera profiles, for lots of good reasons, that comment is moot too.
3. Your site shows a before image with a profile. Is this a custom profile you built from a ‘standard’ available target and if so, which target using what software? IF it’s C1’s canned profile, your examples are rather worthless sorry. You can’t compare a canned profile (built using any target) to your custom profile with your target. So hopefully you’ll tell us that the before is a custom profile in C1 using a differing (and inferior) target.
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I can easily debate some of the conclusions you have drawn and stated above, but I won't. Good luck with your project. I'm happy you are happy :)
Mark, for the sake of other forums members like myself who are curious and eager to learn, please share your insights!
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Mark, for the sake of other forums members like myself who are curious and eager to learn, please share your insights!
Sam, no, please don't go there with me! I truly believe there are limits to what we can accomplish in a forum discussion, and I feel expending further intellectual and emotional capital on a new product I've never seen nor used is not fair to me nor to the OP who is clearly proud of his new product.
I will leave everyone here with one parting comment, however, and it comes from my experiences in one of my former lives, namely as a co-owner of Old Town Editions, Inc back in the 1990s where we did many many fine art repros of original artwork on an Iris 3047 printer (notice how I avoided using the term "giclee" ;D). The challenge wasn't mapping in-gamut source color to in-gamut destination color. The challenge was to map out of gamut colors (ones that failed to reproduce realistically in the camera capture and even less so in the print output, for example, extremely vivid fluorescent dyes as are used commonly in the textile industry, and so forth, in the original art). When faced with that challenge, it came down to one's photoshop and printmaking skills, and working closely with the client, to resolve the problems in a subjectively pleasing, albeit, colorimetrically inadequate way. I got lot's of in-the-trenches experience that's hard to describe objectively. So, for example, in the sample Hugo posted earlier in this thread of Capture 1 versus ACR initial "default" camera output, I can work with either one of those images with equal success. The ACR rendition, IMHO, is closer to reality colorimetrically, whereas, the Capture 1 version is more "pleasing" to folks loving more "pop" in their images. Yet either one is an acceptable starting point to a personally envisioned end result, IMHO, so I don't get hung up at the camera capture step. I spend my time on the workflow from edited source original to final output printed image.
That's just me. If you can find a camera capture technique that nails it right in the first step of the source file to final output workflow or even gets us just a little closer to it more often than not, then go for it. 8)
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ICC profiles take place on rendered data that might be either, NOT the raw data.
in real life they do operate how software developer wants, not how ICC (organization) says they should be used... ICC in that case is just a container... that was noted here on this same forum many times.
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It's 'finger-printing' as best it can, the rendered (output referred) image.
you don't need a rendered image to create camera profiles in icc/icm containers for raw converters like C1... they can be created directly from raw data (raw files) using tools like rawdigger and dcamprof w/o using C1 itself at all ... this was again noted many many times in this forum
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whereas, the Capture 1 version is more "pleasing" to folks loving more "pop" in their images.
just because manufacturer decided so by tuning camera profiles to their vision of how rendering shall be - it is not an genetic feature of C1 somehow...
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The SG had a wider gamut using glossy patches but it was a bitch and a half to shoot (no reflections please). Then they came up with a newer target without the glossy patches but smaller color gamut.
you mean DC chart (the one that was with "glossy" patches --> http://www.chromaxion.com/information/colorchecker_dc.html ) actually and then they come up with with SG ... getting old, Andrew, forgetting things ;D
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you don't need a rendered image to create camera profiles in icc/icm containers for raw converters like C1... they can be created directly from raw data (raw files) using tools like rawdigger and dcamprof w/o using C1 itself at all ... this was again noted many many times in this forum
Yes, you're correct in the case of the two products you speak of. Now how raw that data is, I can't say. The majority of other products no.
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you mean DC chart (the one that was with "glossy" patches --> http://www.chromaxion.com/information/colorchecker_dc.html (http://www.chromaxion.com/information/colorchecker_dc.html) ) actually and then they come up with with SG ... getting old, Andrew, forgetting things ;D
I sit corrected ;D but indeed, there are two such targets, one with glossy patches and a wider gamut, difficult to capture. There's one without, easier to capture. I have both of course and at the time, spent a lot of time working directly with GMB (still have some hand made targets). Haven't used them in like 10 years: no reason to do so.
Getting old, yes. Beats the alternative. ;)
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I've used both the SG CC and the regular CC. The SG has significantly larger gamut but one has to go to lengths to avoid reflections. But it can be done with care and understanding in a studio. Not trivial though.
Of course with the SG one won't get linear mapping because the spectral diversity doesn't nicely map into a camera's RGB response . With a printed chart with a large number of patches, one can get quite low dEs. Under 1.0 ave is fairly easy. But it's because the inks don't have much spectral diversity. So it's a fairly simple job to get pretty much any camera's RGB RAW capture to map colorimetrically. But it's an illusion. Capturing real life images will see metameric error. OTOH, capturing images of printed fine art can be quite accurate as the CMY spectral characteristics tend to be similar form printer to printer.
So it all depends on what you are trying to replicate. Printed materials tend to be more accurately rendered with profiles made from printed charts. OTOH, oils, will not be captured as accurately.
The OP's approach should work quite well capturing printed materials. But how well it captures real life or painted materials is sort of a crap shoot. OTOH, there is no way to do that really well without multiple exposures using color filters that are then processed. There are academic works that delve into this. Especially from RIT.
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OK, let me know what you already predicted and concluded just by looking at the samples (I guess you also got the reference spectral file and did some calculations and research...).
1) Why CC24 colors are distorted on "calibrated" sample image?
(https://www.hugorodriguez.com/blog/wp-content/uploads/2019/07/rosa-fosforito-Standard.jpg)(https://www.hugorodriguez.com/blog/wp-content/uploads/2019/07/rosa-fosforito-Calibrated-Adobe.jpg)
2) Why target producers like X-Rite ettc. are so stupid that they don't print targets like you when it's 100x cheaper?
3) If your idea is so clever, why not just use a target displayed on a reference color critical wide gamut monitor without the whole printing hassle?
4) All joking aside - can you provide spectral measurements of your target?
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Hi andrew,
Couple points:
1. This comment about linear or non linear is moot. ICC profiles take place on rendered data that might be either, NOT the raw data.
I'm sorry but I don't get the point. Of course ICC profiles take place after RAW data has been put into a standard file, and those data can be either.
What I said is that I'm not that sure that camera response is absolutely linear when it comes to color render.
2. There is no such thing as ‘no setting’ in ACR/LR. You might not like the defaults (dirt rendering?) but they can easily be changed and since these products CANNOT use ICC camera profiles, for lots of good reasons, that comment is moot too.
What I meant with no setting is that there was no change in the default settings. It might be something related to the language, as in my native language (castilian spanish) it's usual to say that.
So 'no setting' = 'default, unchanged setting'.
Of course if I don't like the defaults I can change that, but what conclusion do you get when comparing two products and one offers a much better result with default setting? 'you can easily change the settings'?
I'd get another conclusion, but it's up to everyone...
Yes, ACR cannot use ICC camera profiles, but I really doubt there are lots of good reasons. Just look at the facts: Capture one gets WAY better color using the same 'old' icc profiles than ACR with the new DCP profiles.
In my country you'll never see any product, fashion, ecommerce pro photographer developing with other than C1. Why?
3. Your site shows a before image with a profile. Is this a custom profile you built from a ‘standard’ available target and if so, which target using what software? IF it’s C1’s canned profile, your examples are rather worthless sorry. You can’t compare a canned profile (built using any target) to your custom profile with your target. So hopefully you’ll tell us that the before is a custom profile in C1 using a differing (and inferior) target.
It's very easy Andrew: it's the generic embedded profile into C1 (or ACR in that case). It's the profile that C1 automatically uses when you open your raw files. Canned profile? I've never heard that, don't know what you mean.
How do Phase one's engineers built that profile is something I don't know, but what do I know is that they aim to 'pleasant' colors, not faithful.
I hope I clarified the questions.
Best regards,
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1) Why CC24 colors are distorted on "calibrated" sample image?
Distorted? Did you notice that image was published in Adobe RGB space, so it should be view in a capable monitor?
The only 'different' thing in that image is that it's slightly underexposed, due to the necessity of phosphor colours that reflect more visible light they receive (-> causing color clipping).
Take a look at this closer crop, just with the babelcolor AVG, with a small downscaling of the tonal range (with simple white output level) to match the white: (see attached images)
2) Why target producers like X-Rite ettc. are so stupid that they don't print targets like you when it's 100x cheaper?
I haven't said they're stupid. Probably because they stick to the custom pigments because they might offer a slight advantage, but this is clearly overcome with the high resolution and the perceptually uniform distribution. Probably the custom pigments also allow them to make more money. But I believe that nowadays these is not an issue anymore.
However, 15-20 years ago it was.
3) If your idea is so clever, why not just use a target displayed on a reference color critical wide gamut monitor without the whole printing hassle?
Because photographing a monitor is a nightmare, and I know it well, trust me. At least from LCD monitors. I haven't tried from OLED monitor yet. I did careful and extensive testing on that and could eliminate 100% the moire in the very capture (no software) but there are lots of problems yet to solve, and they aren't small. It's way easier from a print.
4) All joking aside - can you provide spectral measurements of your target?
Yes, of course. I'm just starting to make the first sample and still don't have the final chart and its file, but this is one of the latest, just without some last-minute changes on skin tones and without the perimetral patches.
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Hi andrew,
I'm sorry but I don't get the point. Of course ICC profiles take place after RAW data has been put into a standard file, and those data can be either.
What I said is that I'm not that sure that camera response is absolutely linear when it comes to color render.
I don't believe it matters considering where the profile is taking effect (the vast majority of raw converters doing so on the rendered data just to access the target for profile creation).
Of course if I don't like the defaults I can change that, but what conclusion do you get when comparing two products and one offers a much better result with default setting? 'you can easily change the settings'?
I'd get another conclusion, but it's up to everyone...
The settings and the profile are completely different. So it's moot if you don't like them. Plus ACR/LR don't use ICC camera profiles so moot again.
Yes, ACR cannot use ICC camera profiles, but I really doubt there are lots of good reasons.
You need to have a conversation with a fellow named Thomas Knoll; heard of him?
Just look at the facts: Capture one gets WAY better color using the same 'old' icc profiles than ACR with the new DCP profiles.
You are entitled to your opinion, you're not entitled to your made up facts. That statement is simply nothing more than your opinion of a subjective rendering and, defaults in ACR by your own admission you have to alter.
In my country you'll never see any product, fashion, ecommerce pro photographer developing with other than C1. Why?
First, please provide actual facts with metrics of how many such photographers work in your country, then the same with how many use C1 vs. anything else. Of course you've got data that examines how every such image was rendered in what raw processor? Please, if you go down such a path with such text, you'll soon see no one here is going to take you seriously.
It's very easy Andrew: it's the generic embedded profile into C1 (or ACR in that case). It's the profile that C1 automatically uses when you open your raw files. Canned profile?
Then your before and after examples are bogus (not acceptable, not good science). I told you WHY.
Are you trying to show us the effect of your target in the creation of ICC camera profiles, yes or no? IF yes, you need an apples to apples comparison and your site is far, far from doing that. Now if, big if, you really want to show the qualities of your new target, make a CUSTOM profile for C1 with any other target, then one with your target and show the differences with the SAME software and settings used to build both. Otherwise, as you have defined above how you've produced the before and after shots on your site, those comparisons are not to be taken at all seriously.
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1) Why CC24 colors are distorted on "calibrated" sample image?
Why, with the exception of the shorts having far more vibrancelSaturation, does everything else in the image look (subjectively) WORSE? ;D
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Following the exercise done here (https://forum.luminous-landscape.com/index.php?topic=130281.0), the only drawback I see in measuring glossy patches is in the darkest ones. I have a feeling it's very difficult or even impossible to properly model the transformation between very dark patches and their expected output values because any residual reflection due to the nature of the printing paper's surface (not its real colour nor brightness in terms of printing density), even unnoticeable to the naked eye, could fool the model (profile) in those darkest patches. A null output (L=0) should only be achieved for a null input (R=G=B=0 in the RAW data), but the fact is that the input (camera) vs expected output (spectrophotometer measurements) curve seems to produce a non-null black point clipping behaviour as seen in this input G vs output L (http://guillermoluijk.com/misc/validation_gvsl.png) curve. I wonder if a possible solution would be avoiding the darkest patches in the card and provide the model (profile) with hard-coded R=G=B=0 to L=0 correspondences. Otherwise what we are doing is correcting veiling glare type effects inherent to the material used to produce the card that do not reflect any sensor's genuine behaviour.
On the contrary, to achieve proper rendition on very saturated synthetic colours, which are much more important for the intended applications of this SuperChroma card, I don't see any reason why a chart like this one couldn't work better than general purpose matte cards like the CC, where extreme colours need strong extrapolation well beyond the colours seen during the creation of the profile.
Regards
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Yes, I have lots of examples that I'm preparing for an article to be published here in the main website, with the kind help ot Kevin, main editor of this site.
If you're referring to Kevin Raber, he hasn't been connected to this site for some time.
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Following the exercise done here (https://forum.luminous-landscape.com/index.php?topic=130281.0), the only drawback I see in measuring glossy patches is in the darkest ones. I have a feeling it's very difficult or even impossible to properly model the transformation between very dark patches and their expected output values because any residual reflection due to the nature of the printing paper's surface (not its real colour nor brightness in terms of printing density), even unnoticeable to the naked eye, could fool the model (profile) in those darkest patches. A null output (L=0) should only be achieved for a null input (R=G=B=0 in the RAW data), but the fact is that the input (camera) vs expected output (spectrophotometer measurements) curve seems to produce a non-null black point clipping behaviour as seen in this input G vs output L (http://guillermoluijk.com/misc/validation_gvsl.png) curve. I wonder if a possible solution would be avoiding the darkest patches in the card and provide the model (profile) with hard-coded R=G=B=0 to L=0 correspondences. Otherwise what we are doing is correcting veiling glare type effects inherent to the material used to produce the card that do not reflect any sensor's genuine behaviour.
Regards
Hi Guillermo,
I think I did the same obeservation too near black point.
Here is a plotted curve from an icc input profile (reproduction profile). I made this profile for C1 with a glossy chart from (very close to your), (many patches between L*7 until L*3.5 measured with i1pro2). I made this profile in the purpose to be as closest as possible by pushing limits of two softwares for testing (3dlutcreator+lumariverPD). My chart is shot in studio with a max controlled on glare/flare.
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Because photographing a monitor is a nightmare, and I know it well, trust me. At least from LCD monitors. I haven't tried from OLED monitor yet. I did careful and extensive testing on that and could eliminate 100% the moire in the very capture (no software) but there are lots of problems yet to solve, and they aren't small. It's way easier from a print.
Photographing a profiled monitor's image of a chart to make a profile works quite well, and isn't that difficult. But only if the monitor's white point is D50 and you want to use the profile to tag pictures the camera takes of the monitor. Otherwise it's useless.
A monitor has 3 primaries that are quite separated in wavelength. Especially wide gamut monitors. You will get large metameric error when applying these to real life camera images or even images of printed material. CYM prints at least spectrally gradually overlap and blend into each other.
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I don't believe it matters considering where the profile is taking effect (the vast majority of raw converters doing so on the rendered data just to access the target for profile creation).
The settings and the profile are completely different. So it's moot if you don't like them. Plus ACR/LR don't use ICC camera profiles so moot again.
This is a perfect example of someone talking about apples and another replying with pears.
Who said the setting and the profile were the same? Who said ACR/LR use ICC camera profiles?
You need to have a conversation with a fellow named Thomas Knoll; heard of him?
Yes, I know who is him, but haven’t had the pleasure to meet him.
But I guess the guy you suggest I talk to is (was) Bruce Fraser, not Thomas. Wasn’t him the guy responsible for the DCP profiles?
Ask yourself many the of most renowned professional product, fashion photographers don't use ACR/Lr.
Anyway, I’m not here to discuss that thing.
You are entitled to your opinion, you're not entitled to your made up facts. That statement is simply nothing more than your opinion of a subjective rendering and, defaults in ACR by your own admission you have to alter.
Of course that is an opinion. But it’s a widely accepted opinion.
Many people agree that when opening a photo in C1 and compare to ACR/Lr, the colors don’t look ‘washed out’, but more clean.
Have you ever used C1?
First, please provide actual facts with metrics of how many such photographers work in your country, then the same with how many use C1 vs. anything else. Of course you've got data that examines how every such image was rendered in what raw processor? Please, if you go down such a path with such text, you'll soon see no one here is going to take you seriously.
1- Seems to me that you don’t know what were the thoughts about C1 of the person that founded this site. Take a look:
https://luminous-landscape.com/capture-one/
May I remember you that Michael was PODAS instructor?
2- Metrics about photographers? Are you kidding me? Go outside, meet some pros (of product, fashion, e-commerce) and ask them what are they using, and you’ll see. I don’t have any data and I doubt there’s such data, but I can have a good idea based and many many photographers I know in my country. Of course I don’t know photographers in your country, but I bet it’s a very similar story.
Then your before and after examples are bogus (not acceptable, not good science). I told you WHY.
Are you trying to show us the effect of your target in the creation of ICC camera profiles, yes or no? IF yes, you need an apples to apples comparison and your site is far, far from doing that. Now if, big if, you really want to show the qualities of your new target, make a CUSTOM profile for C1 with any other target, then one with your target and show the differences with the SAME software and settings used to build both. Otherwise, as you have defined above how you've produced the before and after shots on your site, those comparisons are not to be taken at all seriously.
Ok, let me sum it up: so you’re telling me that just because I didn’t use the examples YOU want, then the examples are ‘bogus’?
What makes you think that the only valid opinion is your opinion?
I used those examples because my target customer is a pro photographer that usually don’t make any camera calibration or has done one with the CC24, but with unsatisfactory results, and usually uses ACR/Lr. That’s why I’m showing the default/custom profile.
But if you ask me for the results and comparison with custom profiles with other charts, yes, of course I’ve done them and I also did careful tests and measurements, which I already have explained in the article I’d like to publish here.
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This is a perfect example of someone talking about apples and another replying with pears.
Who said the setting and the profile were the same? Who said ACR/LR use ICC camera profiles?
No one. I said your comments about ACR were moot, they are. Do examine who brought up ACR here: YOU did (Reply #14 on: July 09, 2019, 03:07:22 pm). After Mark simply stated he used that product.
The apples to pear comparison is all yours; on your site. The bogus before and after shots!
Yes, I know who is him, but haven’t had the pleasure to meet him.
Then you don't know him.
But I guess the guy you suggest I talk to is (was) Bruce Fraser, not Thomas
First, Bruce passed away many years ago so no. 2nd, Bruce and I were partners in a software company and very, very good friends. So I know the history.
Wasn’t him the guy responsible for the DCP profiles?
No. It was Thomas who did all the coding. But this is OT, you're way out of the loop on this part of the subject.
Ask yourself many the of most renowned professional product, fashion photographers don't use ACR/Lr.
That's an impossible question to ask, you're suggesting someone poll all such photographers and get their actual response as to what raw converters they or more likely, their tech's use.
I can give you a list of very well known photographers such as Greg Gorman, Jay Maisel, Steven Wilkes, Jeff Schewe, Seth Resnick, Martin Evening, Andy Katz, Art Wolfe, JP Caponigro, to name just a few, use ACR/LR.
Anyway, I’m not here to discuss that thing.
You shouldn't try, you're not up to speed on that part of the discussion.
Of course that is an opinion. But it’s a widely accepted opinion.
Rubbish, prove it or move on.
Many people agree that when opening a photo in C1 and compare to ACR/Lr, the colors don’t look ‘washed out’, but more clean.
Have you ever used C1?
Yes I have and: "All generalizations are false, including this one".-Mark Twain
You came here for feedback sir, you got it. First and foremost, your examples are bogus! It's interesting you've decided not to take up that important part of this discussion too. You're trying to show how well your target preforms and you've stacked the deck unfairly by showing a canned camera profile produced with who knows what target and software against your target with who knows what software and expect us to say "Wow, look how much better your examples are" but of course, as seen here with the image of the shorts, it looks WORSE!
You have a lot of work to do sir, after you've corrected the bogus examples on your site with a fair comparison of JUST what your target can do, we can move on.
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Why, with the exception of the shorts having far more vibrancelSaturation, does everything else in the image look (subjectively) WORSE? ;D
Ok, I think you’re going too far. I replied and gave arguments, screenshots and answers to every single critic that you told me; all I see from you is a person that simply jumps to another new small detail to criticize when I reply to the last one. And in this your last post, you're laughing about the project I've been working slowly for 4 years.
Let me tell you something, Andrew: when I came here to share this my project, I expected to have a nice discussion with many experts here. A discussion on where some would like my chart and some don’t. I will totally respect their opinion, of course, but as well as I would never throw shit over other person’s project, I expect them to not do that to me. Because I know he may have spent hundreds, thousands of hours on it, that would be a really dirt thing from myself to do that. Because that hurts.
There always should be a respect for others work, because we can all discuss without going low.
Let's say you have written a book (I know you did) and come to a forum to share it. I’d first ask about several things. Never criticize first. Get all the important information, then I can discuss with arguments. In the end, if I don’t like it, I just don’t buy it! But I'd never start a ‘campaign’ to discredit, even less with childish arguments that take the tangent path from the important stuff.
Now I see you’re not that kind of person. I hope you don’t face with that in your own person from others.
So now you’re telling me that the everything else in the image looks 'WORSE'. And you laugh.
You might not seen the answer and images of the CC24 I've already posted, on where it can be seen that the profiled capture is almost spot on.
But after you said that, now I can see that you ignore how phosphor colors behave, which in the end tells me that you might know Ps very well, but regarding camera profiling you're lacking quite some knowledge.
Also, if you ever come to a Spanish forum on where I use to be, I will first welcome you (because that’s gentleman do when a new one comes and introduces himself) and then will start to discuss. But I won’t try to find out any mistake or misspelling in your book just to hit hard with my finger on it. In fact, if I find some I will email you privately just to help you correct it. That’s my DNA, and i.e. Guillermo knows that.
I don't know if you know Chris Murphy or if he is also here, but you can ask him how did I treated him when I managed to bring him to a big intl. photo show in Barcelona a few years ago. We both performed a conference about color management, together.
Would you like if I read your book and post here every single and small mistake I find out? And, trust me, I will find them. Even that it’s not in my mother language.
Now, that said, let me answer the main question: That 'strange', 'WORSE' appearance is totally normal when faithfully reproducing phosphor colors, because they reflect more visible light than they receive, thus need under-develop, to avoid color clipping. That makes the non-phosphor colors underexposed.
The CC4 was almost spot-on, except for the scaling down of the RGB values.
Now, let me tell you that I wasted enough time replying to this; I won’t be replying unless you keep a respectful position.
PS: Regarding your last post, If you ever asked me to add another examples to make the comparison more fair/complete/real/whatever, I’d kindly find some time to add them. Now you achieved the opposite from me.
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If you're referring to Kevin Raber, he hasn't been connected to this site for some time.
Oh, really?
Ok, I see now it's Josh. Is he michael's brother?
Regards,
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Ok, I think you’re going too far. I replied and gave arguments, screenshots and answers to every single critic that you told me; all I see from you is a person that simply jumps to another new small detail to criticize when I reply to the last one. And in this your last post, you're laughing about the project I've been working slowly for 4 years.
So the before's examples are using what target and built by you as custom camera profiles with what software? Did I miss that answer? If so, I apologize. Please clarify or point me to that text.
Let me tell you something, Andrew: when I came here to share this my project, I expected to have a nice discussion with many experts here.
That might have been a mistake as you've seen.
A discussion on where some would like my chart and some don’t.
I don't have enough data to tell you if I like or dislike it. Just like you don't have enough data to tell us how many pro photographers ALL use C1.
I will totally respect their opinion, of course, but as well as I would never throw shit over other person’s project, I expect them to not do that to me.
Shit? was thrown at the before and after examples as interpreted. Again, is the before image on your site a custom profile and if so, using what current target?
There always should be a respect for others work, because we can all discuss without going low.
Respect is earned.
So now you’re telling me that the everything else in the image looks 'WORSE'. And you laugh
I believe I made clear what I subjectively saw of that one image and what looked 'better' and all the rest that looked worse. The paper trail of my comments remain here to see.
Please show me the paper trail of yours, that perhaps I missed, that describes how your "before" examples were built using a CUSTOM camera profile as a comparison to the custom profile examples made with your target.
You might not seen the answer and images of the CC24 I've already posted, on where it can be seen that the profiled capture is almost spot on.
OT
But after you said that, now I can see that you ignore how phosphor colors behave, which in the end tells me that you might know Ps very well, but regarding camera profiling you're lacking quite some knowledge.
OT, I've ONLY commented so far on two attributes: A comparison that thus far appears to be unfair. A single image that I believe looks worse with the application of your profile. It's subjective of course.
Also, if you ever come to a Spanish forum on where I use to be, I will first welcome you (because that’s gentleman do when a new one comes and introduces himself) and then will start to discuss.
Then ask questions who's answers you wish to hear on a Spanish photo forum; I have no desire and will not be posting on any such site.
But I won’t try to find out any mistake or misspelling in your book just to hit hard with my finger on it.
I haven’t and don't believe anyone else is taking you to task about spelling are they? IF so, point that post out to me. Or stop playing the victim.
I don't know if you know Chris Murphy or if he is also here, but you can ask him how did I treated him when I managed to bring him to a big intl. photo show in Barcelona a few years ago. We both performed a conference about color management, together.
I know Chris quite well and for decades, but your comments are again off topic.
Would you like if I read your book and post here every single and small mistake I find out? And, trust me, I will find them. Even that it’s not in my mother language.
I haven’t and don't believe anyone else is taking you to task about spelling are they? IF so, point that post out to me. Or stop playing the victim.
Now, that said, let me answer the main question
:
Yes please: HOW were the 'before" images on your site produced with respect to the target used and the software used to build them? OR are they canned C1 camera profiles?
Now, let me tell you that I wasted enough time replying to this; I won’t be replying unless you keep a respectful position.
And I've wasted enough time too. But then, who came here asking for feedback? Wasn't me.
PS: Regarding your last post, If you ever asked me to add another examples to make the comparison more fair/complete/real/whatever, I’d kindly find some time to add them. Now you achieved the opposite from me.
I'm asking you to explain how ALL the 'before' images were produced with respect to a target and generation of the camera profile. That's all I'm asking. IF as I believe but may be wrong, the 'Before' images were all canned C1 profiles, your examples ARE bogus. And I explained HOW you could fix that issue and show us JUST what your target provides using an apples to apples comparison. CAN or DID you do this? Yes or no?
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Oh, really?
Yes, really.
Ok, I see now it's Josh. Is he michael's brother?
No. ???
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Shooting targets are not really high quality profiling. And it is not easy either. Too much investment into proper lighting setup, flat fielding, fighting with flare/glare from highly reflective patches and so on. The ultimate solution if you want quality in your profiles is to measure spectral sensitivity of the sensor, spectral transmission of the lenses and filters (so the complete spectral profile for camera+lens+filter could be obtained), measure the lighting spectra and build profile targeting specific set of colour samples you need for high quality reproduction from that data. That approach will allow any samples to be used and resulting profile optimised for those sample colours.
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Shooting targets are not really high quality profiling. And it is not easy either. Too much investment into proper lighting setup, flat fielding, fighting with flare/glare from highly reflective patches and so on. The ultimate solution if you want quality in your profiles is to measure spectral sensitivity of the sensor, spectral transmission of the lenses and filters (so the complete spectral profile for camera+lens+filter could be obtained), measure the lighting spectra and build profile targeting specific set of colour samples you need for hi quality reproduction from that data. That approach will allow any samples to be used and resulting profile optimised for those sample colours.
+1!
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This needs to be explained a bit more too:
It should be noted that in the developing there is no adjustment of any kind, except the WB and the color profile. No styles, no color editing, no layers, no masks or anything similar.
All images on the site with all Before shots? Because, with a 5x5 sampler in Photoshop of the before, I'm hard pressed to see where WB was set:
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Photographing a profiled monitor's image of a chart to make a profile works quite well, and isn't that difficult. But only if the monitor's white point is D50 and you want to use the profile to tag pictures the camera takes of the monitor. Otherwise it's useless.
A monitor has 3 primaries that are quite separated in wavelength. Especially wide gamut monitors. You will get large metameric error when applying these to real life camera images or even images of printed material. CYM prints at least spectrally gradually overlap and blend into each other.
Photographing an image in a monitor is easy, but capturing a very high quality capture from a monitor, with absolutely no hue shifting from corner to corner (even with IPS), 100% free of moire and 100% perfect focus and fine detail is very hard to achieve.
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It's very easy Andrew: it's the generic embedded profile into C1 (or ACR in that case). It's the profile that C1 automatically uses when you open your raw files. Canned profile? I've never heard that, don't know what you mean.
How do Phase one's engineers built that profile is something I don't know, but what do I know is that they aim to 'pleasant' colors, not faithful.
What you say is correct for Capture One Pro - they aim for pleasing color
Capture One CH (https://dtculturalheritage.com/capture-one-ch/) on the other hand has profiles meticulously created and test for absolute accuracy.
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Photographing an image in a monitor is easy, but capturing a very high quality capture from a monitor, with absolutely no hue shifting from corner to corner (even with IPS), 100% free of moire and 100% perfect focus and fine detail is very hard to achieve.
Moire's easily removed by very slight defocussing. It isn't even necessary to remove it all since you are adding all the pixels within a subset of each patch. You have to work pretty hard before moire, even if visible, alters the average patch color more than a fraction of a dE.
You are correct that hue changes are an issues when off 90 degrees. There are also L* differences across the face of a monitor and they can be pretty significant. In fact they can vary even more than hue over just a fewn inches. Even with high end monitors. But that is overcome effectively by using a large, randomized, patch set and is helped significantly by the relatively (compared to printers) independent response monitors tend to have. I did some work on this as a possible approach to profiling monitors (not cameras) . It's quite easy and produces excellent profiles except that it has one, major, problem. Camera response is not intrinsically colorimetric so you also have to have a spectroradiometer to measure the primaries and set the white point. And if you have that you can just use it to create monitor profiles. So it was just an interesting experiment.
But all that aside, even with a "perfect" monitor one can't produce good camera profiles this way unless one wants to take pictures of images from the same monitor. Might be something an academic might do but there is no reason anyone else would that I can imagine.
Also, your printer charts should do quite well for repro work where your images are printed materials. At least those printed with CYMK processes. I've used a similar approach here to profile my scanner. I wound up using around 2k of randomized patches. And the profiles worked quite well across my three printers. Better than a CC, IT8, or CCSG scanner profile. But the bigger problem with scanners is something called large area crosstalk that is intrinsic to most all reflection scanner designs. It can be a much larger problem than metameric error and, like metameric error, can't be solved by any profiling technique. Luckily, it doesn't affect transmission scans nor is it a significant issue for cameras.
Careful not to conflate accuracy with what looks good. Accuracy is meaningful only for scene referred images where one can actually used dE stats. And generally, colorimetrically accurate prints are only useful for reproduction work where the goal is to make a copy indistinguishable from the original when viewed side by side. The same process will produce rather unappealing prints in almost all other uses.
As another aside, when I see PR stuff like claims of "Absolute Accuracy" from a camera profile I chalk the rest of the claims to marketing blather. Camera CFA responses are not linearly congruent to L/I or even very close.
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This needs to be explained a bit more too:All images on the site with all Before shots? Because, with a 5x5 sampler in Photoshop of the before, I'm hard pressed to see where WB was set:
The problem with those who think that know everything is that is hard to make them understand they don't.
Do you know what color was the background or what lighting was used, sir?
That's the real question.
PS: I don't know why I'm still replying you.
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What you say is correct for Capture One Pro - they aim for pleasing color
Capture One CH (https://dtculturalheritage.com/capture-one-ch/) on the other hand has profiles meticulously created and test for absolute accuracy.
I didn't know that CH profiles were different from the other versions. Does it come with these profiles for every single camera?
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What you say is correct for Capture One Pro - they aim for pleasing color
Either or, the examples shown on the site ARE bogus, as the author of the target is comparing a canned camera profile to a custom profile.
AGAIN, a fair test would be to have both profiles be identical in creation EXCEPT for the targets being different. Then and only then would we see what that target brings to the party.
The examples (before) also are not fair to PhaseOne either, but that's kind of besides the point.
Capture One CH on the other hand has profiles meticulously created and test for absolute accuracy.
Then, if so, if the profiles are meticulously created for absolute accuracy (a dE report would be lovely), the new target isn't going to bring anything to the party. ;D
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PS: I don't know why I'm still replying you.
"It is better to say nothing and be thought a fool than to open your mouth and remove all doubt".- Abraham Lincoln ::)
I didn't know that CH profiles were different from the other versions.
Even more reason to dismiss the presentation.....
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Then, if so, if the profiles are meticulously created for absolute accuracy (a dE report would be lovely), the new target isn't going to bring anything to the party. ;D
Well. it would be interesting to test whether C1 CH's 'absolute accuracy' is indeed so by capturing Hugo's target with it :)
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Well. it would be interesting to test whether C1 DH's 'absolute accuracy' is indeed so by capturing Hugo's target with it :)
Brilliant idea.
And if the claim is true, then Hugo should update all the "before" images on his blog with that rendering using this canned profile. Plus, I still think (beating a dead horse), create a CUSTOM profile using whatever target, other than his own, to compare with a profile made with his target.
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Shooting targets are not really high quality profiling. And it is not easy either. Too much investment into proper lighting setup, flat fielding, fighting with flare/glare from highly reflective patches and so on. The ultimate solution if you want quality in your profiles is to measure spectral sensitivity of the sensor, spectral transmission of the lenses and filters (so the complete spectral profile for camera+lens+filter could be obtained), measure the lighting spectra and build profile targeting specific set of colour samples you need for high quality reproduction from that data. That approach will allow any samples to be used and resulting profile optimised for those sample colours.
Well, I think a pro photographer and/or a color management technician can do some things to achieve a quite fine reproduction without all that. Just with a good camera, good lighting and a good chart and software.
How many photographers or color mngmt consultants do have such equipment?
I don't want to seem ironic, but if we follow your recommendations, what would be the next step? Call the NASA?
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Moire's easily removed by very slight defocussing. It isn't even necessary to remove it all since you are adding all the pixels within a subset of each patch. You have to work pretty hard before moire, even if visible, alters the average patch color more than a fraction of a dE.
I don't agree with that. Yes, with slight defocusing you avoid high resolution moire, but unless you're capturing the monitor at a very low res (i.e: just filling a small rectangle in the frame), you'll have other moires at different resolutions. Even focusing way behind or ahead the monitor, and even with a 16MP camera you have some sort of interference.
Maybe moire is not the right word, but you won't get a 100% clean image like if it was a print.
You are correct that hue changes are an issues when off 90 degrees. There are also L* differences across the face of a monitor and they can be pretty significant. In fact they can vary even more than hue over just a fewn inches.
OLED monitor can be a solution with that. I've calibrated several SONY A250 for some big cinema studios but couldn't try this experiment.
Even with high end monitors. But that is overcome effectively by using a large, randomized, patch set and is helped significantly by the relatively (compared to printers) independent response monitors tend to have. I did some work on this as a possible approach to profiling monitors (not cameras) . It's quite easy and produces excellent profiles except that it has one, major, problem. Camera response is not intrinsically colorimetric so you also have to have a spectroradiometer to measure the primaries and set the white point. And if you have that you can just use it to create monitor profiles. So it was just an interesting experiment.
Very interesting. That sounds similar to the characterizaction of the embedded EIZO colorimeter, but handmade.
But all that aside, even with a "perfect" monitor one can't produce good camera profiles this way unless one wants to take pictures of images from the same monitor. Might be something an academic might do but there is no reason anyone else would that I can imagine.
Also, your printer charts should do quite well for repro work where your images are printed materials. At least those printed with CYMK processes. I've used a similar approach here to profile my scanner. I wound up using around 2k of randomized patches. And the profiles worked quite well across my three printers. Better than a CC, IT8, or CCSG scanner profile.
That statement makes a lot of sense.
But the bigger problem with scanners is something called large area crosstalk that is intrinsic to most all reflection scanner designs.
I've never heard about that. Is that related to film, flatbed, virtual drum? Can you elaborate, please?
It can be a much larger problem than metameric error and, like metameric error, can't be solved by any profiling technique. Luckily, it doesn't affect transmission scans nor is it a significant issue for cameras.
Careful not to conflate accuracy with what looks good. Accuracy is meaningful only for scene referred images where one can actually used dE stats. And generally, colorimetrically accurate prints are only useful for reproduction work where the goal is to make a copy indistinguishable from the original when viewed side by side. The same process will produce rather unappealing prints in almost all other uses.
I don't agree with 'colorimetrically accurate prints are only useful for reproduction work'. There are many other fields where accuracy is very important, like biology, product & fashion photography, commercials...
As another aside, when I see PR stuff like claims of "Absolute Accuracy" from a camera profile I chalk the rest of the claims to marketing blather. Camera CFA responses are not linearly congruent to L/I or even very close.
I think you're taking the term absolute too literally. I guess what he means with absolute is as good as is close to perfect.
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Well. it would be interesting to test whether C1 CH's 'absolute accuracy' is indeed so by capturing Hugo's target with it :)
Yes, that would be a good test, but C1 CH is a completely different story and as far as I know, cannot be downloaded. And it can only be used with their own cameras.
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I don't agree with that. Yes, with slight defocusing you avoid high resolution moire, but unless you're capturing the monitor at a very low res (i.e: just filling a small rectangle in the frame), you'll have other moires at different resolutions. Even focusing way behind or ahead the monitor, and even with a 16MP camera you have some sort of interference.
It might surprise you but even highly visible moire, with the exception of long wavelength moire, has little to no affect on the patch averages. The physics demands it. Even in the case of longer wavelength moire, using a Hann window is effective at measuring the light consistently. One just has to keep the moire at relatively high frequencies. Say, a wavelength of 10 pixels or less for a reasonably high re monitor. It's usually much smaller than that.
I've never heard about that. Is that related to film, flatbed, virtual drum? Can you elaborate, please?
Flatbed. Large area crosstalk is intrinsic to the design of virtually all of them.
I don't agree with 'colorimetrically accurate prints are only useful for reproduction work'. There are many other fields where accuracy is very important, like biology, product & fashion photography, commercials...
There are a few areas aside from repro that use scene referred profiles. Biology and scientific work, yes. Product and fashion photography, not so common. By definition output referred profiles distort an image, typically increasing contrast in midrange while decreasing it at the high and low Ls. Scene referred profiles also have the intrinsic limitation of the output medium's dynamic range. And people are used to seeing photos that are made that way. To the point that a colorimetrically accurate print will look unattractive next to a standard print made using an output referred process. Just look around and see just how little scene referred profiles are used.
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There are a few areas aside from repro that use scene referred profiles. Biology and scientific work, yes. Product and fashion photography, not so common. By definition output referred profiles distort an image, typically increasing contrast in midrange while decreasing it at the high and low Ls. Scene referred profiles also have the intrinsic limitation of the output medium's dynamic range. And people are used to seeing photos that are made that way. To the point that a colorimetrically accurate print will look unattractive next to a standard print made using an output referred process. Just look around and see just how little scene referred profiles are used.
Absolutely agree on all points. Hugo might wish to see what two of us on the ICC photography committee had to say on this in a white paper aimed at photographers:
http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf (http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf)
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Absolutely agree on all points. Hugo might wish to see what two of us on the ICC photography committee had to say on this in a white paper aimed at photographers:
http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf (http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf)
Yeah, surprising little awareness of this in the general photography community.
This is why I roll my eyes when people talk about "accuracy" and standard, output referred images in the same breath. Now with printers one can talk accuracy but even then there's Perceptual intent. Still, the changes PI induces are small compared to the much larger ones typical of capture devices using output referred profiles. And that's quite apart from metameric shifts from L/I deviation in the CFA. A whole other can of worms.
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Well, I think a pro photographer and/or a color management technician can do some things to achieve a quite fine reproduction without all that. Just with a good camera, good lighting and a good chart and software.
How many photographers or color mngmt consultants do have such equipment?
I don't want to seem ironic, but if we follow your recommendations, what would be the next step? Call the NASA?
Photographers went down that road for quite a few years.
And taking reliable spectral curves with even modest setup (all manual) is much simpler than getting target shots correctly - I did post that somewhere on dcamprof thread here a few years ago. Then Iliah Borg and I worked on making automated solution to do this (see here (https://github.com/Alexey-Danilchenko/Spectron) if interested - the project is still ongoing). The end result is that you can build high quality tuned profile without reshooting your target in required lighting conditions. Bottomline - there is no universal target for all cases that will allow you to correctly approximate sensor response adjustments and behavior in any given lighting (and that is what profile does).
And last, given your reply above, I'd like to quote your own earlier reply to Andrew right back at you:
The problem with those who think that know everything is that is hard to make them understand they don't.
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By definition output referred profiles distort an image, typically increasing contrast in midrange while decreasing it at the high and low Ls. Scene referred profiles also have the intrinsic limitation of the output medium's dynamic range.
Hi Doug, not sure if I understand what you mean here by distorting the original image. Let's assume our output device can handle without any limitation both the dynamic range and the colour gammut of the captured scene. With a properly profiled camera (let's forget the method, we are just certain we can convert its RAW values into exactly the expected colour values a spectrophotometer would measure), and a properly calibrated output device (again let's forget the method to achieve that, this monitor/projector/print can simply render the colours exactly as they are defined in the PCS).
Why should there be any difference in contrast or colours between when looking at the original scene vs looking at the output device render?. I know it's an hypothetical scenario, just to understand your claim of the image distortion.
Regards
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I'll let Doug express his ideas of 'distort' but the ICC white paper describes this way:
In technical jargon, the measured scene color the camera captures is known as Scene-Referred. Since we need to view this image on something like a display or a print, it’s usually necessary to make the image appear more pleasing on the output device and to produce the desired color appearance the image creator wishes to express and reproduce. These image colors are known as Output- Referred. The need to fit the color gamut and dynamic range of the scene-referred data to output referred data is called rendering.
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Why should there be any difference in contrast or colours between when looking at the original scene vs looking at the output device render?. I know it's an hypothetical scenario, just to understand your claim of the image distortion.
It's not so much of a difference between original scene and output but original scene as captured by camera and output.
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I'll let Doug express his ideas of 'distort' but the ICC white paper describes this way:
In technical jargon, the measured scene color the camera captures is known as Scene-Referred. Since we need to view this image on something like a display or a print, it’s usually necessary to make the image appear more pleasing on the output device and to produce the desired color appearance the image creator wishes to express and reproduce. These image colors are known as Output- Referred. The need to fit the color gamut and dynamic range of the scene-referred data to output referred data is called rendering.
Thanks Andrew, I read the paper before asking Doug. However this doesn't answer the question as to why should the render get any distortion vs the original image assuming the output device can handle both the DR and colour gammut of the original scene, and that all our workflow was aimed at getting accurate reproduction. In other words, why can't I look at a printed copy of a colour chart I captured with my profiled camera/scanner and then printed again with my properly profiled printer. Why should I look at them both and see any contrast or colour distortion?.
EDIT: sorry, my fault, that's understood and agreed. I re-read what Dough said; I thought he said: "By definition output scene referred profiles distort an image ...".
Regards
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Thanks Andrew, I read the paper before asking Doug. However this doesn't answer the question as to why should the render get any distortion vs the original image assuming the output device can handle both the DR and colour gammut of the original scene, and that all our workflow was aimed at getting accurate reproduction.
That is of course possible but unlikely in many situations. This is well illustrated visually and textually in this white paper by Karl Lang:
http://www.lumita.com/site_media/work/whitepapers/files/pscs3_rendering_image.pdf (http://www.lumita.com/site_media/work/whitepapers/files/pscs3_rendering_image.pdf)
Again, the term rendering is used and I like that term, but "distorting" could certainly be another way of suggesting this. ;)
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That is of course possible but unlikely in many situations. This is well illustrated visually and textually in this white paper by Karl Lang:
http://www.lumita.com/site_media/work/whitepapers/files/pscs3_rendering_image.pdf (http://www.lumita.com/site_media/work/whitepapers/files/pscs3_rendering_image.pdf)
Again, the term rendering is used and I like that term, but "distorting" could certainly be another way of suggesting this. ;)
I'll give it a careful read, but I have a feeling the text focus on the (taken from the text): "The reality is that light levels in a natural scene can’t be reproduced using any current technology and certainly not in a print." assumption.
I wouldn't agree with that unless the author added some 'in most cases', but he didn't. I started to think about these matters years ago when processing HDR captures, and concluded that the key for HDR imaging is not at all the capture (which can be easily solved with just a couple of shots), but what's the dynamic range of the output device in which the images are to be viewed. If our output device can provide both the real contrast (dynamic range) and the genuine colours (gamut) present in the original scene, why shouldn't I be able to render that scene on the output device in a nearly indistinguishable way to my eye?.
Take a foggy day, to ensure low contrast and dim colours:
(http://guillermoluijk.com/article/histogram/niebla.jpg)
If my workflow is aimed at the goal of getting exactly the same L and colours for every area of the scene, why can't I get a print, a projection, or a monitor view with exactly the same colours and contrast I saw with my eyes in the foggy landscape?. Note I don't mean it will always be possible, nor that it will be the most pleasant image. I just disagree with the "light levels in a natural scene can’t be reproduced" generalization. It will basically depend on how powerful in terms of contrast and colours our output device is. This could be totally offtopic but also leads me to think that the best way to look at photographs is not a print (highly limited output device), but much more powerful active devices such as large gamut and resolution screens.
Regards
PS: sorry for the offtopic Hugo
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Check figure 3.
This represents a scene dynamic range of 100,000:1.
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Check figure 3.
This represents a scene dynamic range of 100,000:1.
That scene can't be represented with any current output device. So what? other scenes can, and I gave a counterexample that makes the generalization false.
The author says: "Scene dynamic range is the key concept to understand" but this is not accurate. The key concept is if the scene dynamic range can be captured and if it fits into the output device's dynamic range.
Regards
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That scene can't be represented with any current output device. So what?
So it has to be rendered to 'fit' any number of current output devices and as such, it's output referred, not scene referred.
As I said, there are obviously scenes that can 'fit' some/all output devices. They may be scene referred but does the image creator like the rendering? In the ICC white paper, you see three examples provided by my co-author, Jack Holms of his family. And the scene referred image isn't 'pleasing' is it? Jack (or the camera producing the JPEG in sRGB), provided two different renderings. Neither can be said to be accurate colorimetrically. They are subjectively better appearing right? They therefore are output referred.
We might (someday) have a camera system and output device that can show us the entire DR of Karl's scene and a device like a display or print that could be shown to us as scene referred. So what IF the rendering isn't pleasing or what the image creator wishes to express? That's the crux of Karl's article: rendering the print image.
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there are obviously scenes that can 'fit' some/all output devices. They may be scene referred but does the image creator like the rendering?
This is what I'm saying Andrew, so the generalization we can read in the paper is false.
And regarding the pleasantness of the pictures, if a render with the same contrast and colours as the original scene, i.e. a totally accurate reproduction, looks less pleasing to anyone than some processing derived from it, it's fine, but it's a totally subjective story. It simply means that the rendering process managed to enhance what our eyes saw in the scene, but this doesn't change the fact that the less pleasant image is closer to what we experienced in front of the subject.
Regards
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Scanners operate under a fixed light, cameras don't. Shooting complex targets under some fixed light (unless the same light is used to capture the scene) is a very limited and obsolete idea. Profiling from spectral response curves solves the issues caused by different lighting conditions much better.
Some questions:
Profiling software is optimized for certain types of targets (unless you are using Argyll, but even with it it is somewhat moot).
Number of patches (and especially the number of patches in gradients) is not a criterion of quality, independence of patches is. This independence correlates with a number of spectrally different pigments in use. How many spectrally different pigments are there in Epson ink? Five?
What's the point of having "neutral" patches around the target, as no existing software knows the locations and can't use those patches for flat-fielding?
What's the point of having very dark "neutral" patches when they have non-Lambertian reflection profile and don't allow to establish black point?
Do you know if profiling software of your choice relies on neutral patches being spectrally flat?
How does this target deal with metameric failure issues, especially given that the solutions hard-wired into profiling software can't deal with unknown targets?
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This is what I'm saying Andrew, so the generalization we can read in the paper is false.
Which paper and what is false?
By definition, scene referred means the colors measured at the scene (if done) and that which is output colorimetrically match. Lab in (measured scene color) = Lab out. When people (like Doug) speak of color accuracy, it better be that case, otherwise how can we define accuracy? Scene referred is colorimetrically accurate but it may not be pleasing or produce a match to something else.
As you know, those of us who have tried doing reproductions digitally, it's really, really hard work. But a scene referred image may not match the original. It may require editing to produce that match. It's therefore no longer scene referred. It's not colorimetrically an accurate reproduction but it may produce a match. We know about issues with Metameric failures which can take place in various areas of this reproduction chain (camera, what's seen on a display, what's output on a printer).
Say the goal is a visual match but some of the measured color (of say a painting) has to differ to produce a visual match, it's not scene referred any longer.
It can still be scene referred but it's not pleasing because there's a mismatch somewhere and when we edit the area of that image to provide a match, it's no longer scene referred. It's been rendered for the goal of a match.
if a render with the same contrast and colours as the original scene, i.e. a totally accurate reproduction, looks less pleasing to anyone than some processing derived from it, it's fine, but it's a totally subjective story.
Yes, no question. But it is output referred IF in order to get the pleasing result, a match, the image had to be edited. It is no longer scene referred. And that's not a problem, it's the solution.
Again, when discussing the two terms (scene or output referred), each defines the measured color and the resulting color having the same or differing measured values.
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It might surprise you but even highly visible moire, with the exception of long wavelength moire, has little to no affect on the patch averages. The physics demands it. Even in the case of longer wavelength moire, using a Hann window is effective at measuring the light consistently. One just has to keep the moire at relatively high frequencies. Say, a wavelength of 10 pixels or less for a reasonably high re monitor. It's usually much smaller than that.
Well, yes, it surprises me. Anyway, I don't feel very confident capturing a screen while I still can see some patterns of different frequency depending on what distance I set the focus to.
Flatbed. Large area crosstalk is intrinsic to the design of virtually all of them.
Crosstalk is a term that doesn't exists in spanish, and the direct translation doesn't make sense, so excuse me if I still don't get the idea. Can you describe the issue precisely?
There are a few areas aside from repro that use scene referred profiles. Biology and scientific work, yes. Product and fashion photography, not so common. By definition output referred profiles distort an image, typically increasing contrast in midrange while decreasing it at the high and low Ls. Scene referred profiles also have the intrinsic limitation of the output medium's dynamic range. And people are used to seeing photos that are made that way. To the point that a colorimetrically accurate print will look unattractive next to a standard print made using an output referred process. Just look around and see just how little scene referred profiles are used.
In spanish we don't know, nor use, these terms 'scene-referred' and 'output-referred', but I I know what you mean.
When you say that output-referred profiles 'distort' I get the point. That's a linear response develop, without any kind of curve to make it more appealing, right?
In product and e-commerce fashion photography (specifically, shots for the brand's website, not those that usually appear in fashion magazines) I explain my customers how to use my output-referred profiles, and they usually use them in plain shots (those on where you can see the garment alone over a flat background).
But when the model wears the garment, they prefer to add the standard curve (output-referred) and keep using the profile. Sometimes, specially in difficult colors they combine two develops: on for the model and the entire scene and the other (output-ref.) for the garment. then they combine both shots in one image.
For them, that means getting accurate color.
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In spanish we don't know, nor use, these terms 'scene-referred' and 'output-referred', but I I know what you mean.
Do you have terms in Spanish for "Relative Colorimetric" or "Black Point Compensation" or "Profile Connection Space"? Because Scene Referred and Output Referred are no different; industry accepted terms, some 'invented' by the ICC etc.
When you say that output-referred profiles 'distort' I get the point. That's a linear response develop, without any kind of curve to make it more appealing, right?
The terms were defined in the white paper and text below.
In product and e-commerce fashion photography (specifically, shots for the brand's website, not those that usually appear in fashion magazines) I explain my customers how to use my output-referred profiles, and they usually use them in plain shots (those on where you can see the garment alone over a flat background).
IF the numbers captured and/or output don't produce the same measured values as the scene, due to editing the numbers, its output referred. It's as simple as that. You don't have to go into curves, gamut etc. You measure a color at the scene using say a Spectrophotometer and you end up with spectral data or perhaps a conversion to Lab. You do the same on whatever is the result of that capture and if they are the same values, if the numbers haven't been edited for a preferred rendering, it's scene referred.
The ICC states this rather clearl (http://www.color.org/scene-referred.xalter)y (http://www.color.org/scene-referred.xalter): (formatting to focus attention on the key points)
A scene-referred image is an image where the image data is an encoding of the colors of a scene (relative to each other), as opposed to a picture of a scene. In a picture, the colors are typically altered to make them more pleasing to viewers when viewed using some target medium.
But when the model wears the garment, they prefer to add the standard curve (output-referred) and keep using the profile. Sometimes, specially in difficult colors they combine two develops: on for the model and the entire scene and the other (output-ref.) for the garment. then they combine both shots in one image.
For them, that means getting accurate color.
Well for them, they should know that's wrong! How can you define accurate color? YOU MEASURE that color and get some numeric value. How do you define if the resulting colors are accurate? You compare the reference to the measurement and produce a deltaE report**. The formula of course plays a role but the point is, once you define how accurate or inaccurate that dE value is (less than 1dE, more than 2dE? Just specify the intended accuracy), NOW and only now do you have a basis for accurate color. Pleasing color cannot be measured!
All this is kind of basic color management FWIW. ;)
**Delta-E and color accuracy
In this 7 minute video I'll cover: What is Delta-E and how we use it to evaluate color differences. Color Accuracy: what it really means, how we measure it using ColorThink Pro and BableColor CT&A. This is an edited subset of a video covering RGB working spaces from raw data (sRGB urban legend Part 1).
Low Rez: https://www.youtube.com/watch?v=Jy0BD5aRV9s&feature=youtu.be (https://www.youtube.com/watch?v=Jy0BD5aRV9s&feature=youtu.be)
High Rez: http://digitaldog.net/files/Delta-E%20and%20Color%20Accuracy%20Video.mp4 (http://digitaldog.net/files/Delta-E%20and%20Color%20Accuracy%20Video.mp4)
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Which paper and what is false?
Karl Lang's paper, and this quote: "The reality is that light levels in a natural scene can’t be reproduced using any current technology and certainly not in a print."
He'd better say: "Light levels in a natural scene can’t generally be reproduced using any current technology and certainly not in a print.". And even that sentence would probably have a date of expiry since active output devices continuousy increase their DR while real world scenes and human vision remain the same.
I somewhat reconciled with Karl Lang when reading: "There are some new (and very expensive) display technologies on the market that have a real dynamic range of 10,000:1 and can produce extremely bright whites. With one of these, we could send a properly exposed scene-referred image directly to the display. The image would look just like we were there, except for the clipping at white and black caused by the sensor.". That is what I expected to read in such an article.
Regards
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Karl Lang's paper, and this quote: "The reality is that light levels in a natural scene can’t be reproduced using any current technology and certainly not in a print."
He'd better say: "Light levels in a natural scene can’t generally be reproduced using any current technology and certainly not in a print.".
True, the idea of a natural scene is vague. Certainly it's not vague nor untrue in Figure 3.
I somewhat reconciled with Larl Lang when reading: "There are some new (and very expensive) display technologies on the market that have a real
dynamic range of 10,000:1 and can produce extremely bright whites.
I don't know what he was referring to based on the date this was released.
What I do know is Karl was the product manager and engineer for both the Radius PressView and Sony Artisan and believe, he knows a good deal about display technology, even if the reference is again vague.
The article was aimed at photographers, the key take away is the idea of rendering the image and as I think has been illustrated, that act has little if anything to do with accurate color or scene referred imagery.
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Photographers went down that road for quite a few years.
I think that you expect from a photographer to be a color scientist. Photographers usually don't want to dig very deep into the technical stuff, and certainly color management represents a nightmare for most of them.
So they like solutions that doesn't make their life even more complicated. As simple as that. :-)
And taking reliable spectral curves with even modest setup (all manual) is much simpler than getting target shots correctly - I did post that somewhere on dcamprof thread here a few years ago. Then Iliah Borg and I worked on making automated solution to do this (see here (https://github.com/Alexey-Danilchenko/Spectron) if interested - the project is still ongoing). The end result is that you can build high quality tuned profile without reshooting your target in required lighting conditions. Bottomline - there is no universal target for all cases that will allow you to correctly approximate sensor response adjustments and behavior in any given lighting (and that is what profile does).
I didn't know about your project, but although it looks very interesting, I don't think a normal photographer would be interested in buy (if it could be bought), learn to use and use it.
Same reason because less than 0,001%? of photographers use advanced tools that can offer more sophisticated results or experimentation, but they are complicated to use, and/or there's few people out there using them, and there's few documentation. Tools like Rawdigger, Rawthrapee and many more.
By the way: do you have information about how to use that and what were the results? Any colorimetric analysis?
And last, given your reply above, I'd like to quote your own earlier reply to Andrew right back at you:
Please don't misunderstand me, I didn't want to seem rude at all. What I was trying to say is that the solution of measuring every spectral curve of the camera sounds rather complicated even for most pro photographers. At least in my country.
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Thanks Andrew, I read the paper before asking Doug. However this doesn't answer the question as to why should the render get any distortion vs the original image assuming the output device can handle both the DR and colour gammut of the original scene, and that all our workflow was aimed at getting accurate reproduction. In other words, why can't I look at a printed copy of a colour chart I captured with my profiled camera/scanner and then printed again with my properly profiled printer. Why should I look at them both and see any contrast or colour distortion?.
EDIT: sorry, my fault, that's understood and agreed. I re-read what Dough said; I thought he said: "By definition output scene referred profiles distort an image ...".
Regards
Hi,
The following is highly simplified and ignores things like color gamut shifts common with standard imaging. The distortion can be shown using just B&W, in-gamut images. Peruse the articles and white papers in www.color.org for in depth look at how gamuts are typically mapped.
Do not take my use of "distort" as a pejorative. It was intended to convey the idea that the image was changed in a way that isn't consistent between different makers, models, and settings and hence can't be easily reversed. Here's a specific example of scene-referred v output referred camera imaging.
Take the following setup. A singular light bulb 10' away from a small target that has two patches on black, one a neutral gray patch and the other white.
A picture is taken in Adobe RGB and the image is inspected in Photoshop. Assume we are perfectly white balanced and the gray patch reads exactly 100,100,100 while the white patch reads 200,200,200.
Now we move the light from 10' away to about 8' away and take a new picture using the same camera settings and inspect the gray patch. It now reads RGB 120,120,120. What should the white patch read?
If we used a scene referred process, the white patch would read 240,240,240. But virtually all other, standard photography processes will produce a value somewhere between 215 and 235. Output referred imaging compresses the light tones and each manufacturer tends to do so based on a proprietary formula.
This is the reason repro people use scene referred processes as it makes it easier to duplicate originals. At least to the degree the originals have a gamut that is within the capabilities of the printer and metameric shifts from the camera's CFA and ink/illuminant aren't too large.
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Crosstalk is a term that doesn't exists in spanish, and the direct translation doesn't make sense, so excuse me if I still don't get the idea. Can you describe the issue precisely?
See this here on LuLa where I show some extremely large dEs in near whites depending on the surrounding colors. Fortunately, this problem doesn't occur in drum or transmission scanning. Camera/lens are subject to glare but this can be controlled and usually has a smaller effect.
https://forum.luminous-landscape.com/index.php?topic=124885.msg1049190#msg1049190
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Oh, really?
Ok, I see now it's Josh. Is he michael's brother?
Regards,
Josh is Michael’s son.
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No. ???
Did you just get up on the wrong side of the bed or what?
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Did you just get up on the wrong side of the bed or what?
Or what. Question answered. :o
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I think that you expect from a photographer to be a color scientist. Photographers usually don't want to dig very deep into the technical stuff, and certainly color management represents a nightmare for most of them.
So they like solutions that doesn't make their life even more complicated. As simple as that. :-)
You underestimate or do not understand photographers - inconsistency of the results is a nightmare and targets will give you precisely that in different lighting. Camera manufacturers, raw processing software vendors already use that approach to build pre-canned profiles for a set of lighting conditions. There are even commercially available solutions albeit not without their problems.
I didn't know about your project, but although it looks very interesting, I don't think a normal photographer would be interested in buy (if it could be bought), learn to use and use it.
"Normal" photographers in your definition would not waste time buying and shooting targets either. If and when they do, they then quite quickly become disillusioned in so called simplicity of this approach. Been there - done that and I am not even a pro(just a hobbyist).
Same reason because less than 0,001%? of photographers use advanced tools that can offer more sophisticated results or experimentation, but they are complicated to use, and/or there's few people out there using them, and there's few documentation. Tools like Rawdigger, Rawthrapee and many more.
Tools like RawDigger give people control and understanding not complications.
By the way: do you have information about how to use that and what were the results? Any colorimetric analysis?
How to use what and results of what? Spectral sensitivity curves for cameras? Yes I did took some - they were quite close to published scientifically measured ones. They also fairly easily validated by taking shots of the measured colours in measured light and comparing to calculated camera response using spectral sensitivity curves. I don't understand the question about colorimetric analysis- if that is about accuracy of the profiles built from the known spectral sensitivity then nothing really stops you to tune profile calculation to any set of target colours as accurately as you need (recalculating the profile is a matter of running a software not reshooting a target, a new target under a new light).
Please don't misunderstand me, I didn't want to seem rude at all. What I was trying to say is that the solution of measuring every spectral curve of the camera sounds rather complicated even for most pro photographers. At least in my country.
Shooting targets correctly especially glossy ones is much more complicated that that.
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Tools like RawDigger give people control and understanding not complications.
Yes, a far more useful tool than any target/profile exercise. At least the photographers I know and have worked with, understanding the basis of optimal exposure is far more important.
And going back to profiles and targets, it's pretty difficult for even novice photographers to have issues shooting a Macbeth 24 patch target and building a .DCP profile for a few illuminants. after which they produce subjectively preferable color moving a bunch of sliders (or picking a preset ;D , they've built). Yes, for those doing high end repro work, those who do want to start (or finish) with output referred color, a different group with differing needs.
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Yes, a far more useful tool than any target/profile exercise. At least the photographers I know and have worked with, understanding the basis of optimal exposure is far more important.
And going back to profiles and targets, it's pretty difficult for even novice photographers to have issues shooting a Macbeth 24 patch target and building a .DCP profile for a few illuminants. after which they produce subjectively preferable color moving a bunch of sliders (or picking a preset ;D , they've built). Yes, for those doing high end repro work, those who do want to start (or finish) with output referred color, a different group with differing needs.
Good summary, Andrew.
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And going back to profiles and targets, it's pretty difficult for even novice photographers to have issues shooting a Macbeth 24 patch target and building a .DCP profile for a few illuminants.
Acceptable profiles - yes. High quality - not in my experience. I did managed to get somewhat better results with QPCards in the past shooting them outdoors in lighting I needed (had CC passport at that time as well for comparison) - though that was 5-6 years ago.
From my point of view, looking at how profiles are generated from all the targets (mathematically), these profiles will be tuned to accurately reproduce specific target colours and not anything else.
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And going back to profiles and targets, it's pretty difficult for even novice photographers to have issues shooting a Macbeth 24 patch target and building a .DCP profile for a few illuminants. after which they produce subjectively preferable color moving a bunch of sliders (or picking a preset ;D , they've built). Yes, for those doing high end repro work, those who do want to start (or finish) with output referred color, a different group with differing needs.
I've been using the X-Rite Passport and software since it came out some years ago. It does give a reasonable profile for the lighting condition that is used and certainly is easy to use. Of course it's only a starting point in the editing process. An artist friend wanted some repro work done for several paintings so that he could have some images for printing cards and flyers. The Passport worked well in the natural light situation that was used to capture the images. Colors were far closer in the Raw files using the profile than without.
I have yet to compare the results with those created by the Lumaiver Profile Designer that Torger and his colleagues developed.
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And going back to profiles and targets, it's pretty difficult for even novice photographers to have issues shooting a Macbeth 24 patch target and building a .DCP profile for a few illuminants. after which they produce subjectively preferable color moving a bunch of sliders (or picking a preset ;D , they've built).
I've dabbled with this, using the Macbeth 24 patch target with my Nikon D800, but in most situations I prefer the canned profiles in ACR.
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From my point of view, looking at how profiles are generated from all the targets (mathematically), these profiles will be tuned to accurately reproduce specific target colours and not anything else.
Yes, 'more pleasing' is what I observe. Perhaps better with a different target. Nothing to do with color accuracy. My main point was:
Few photographers need anything else IF using a raw converter that supports .dcp profiles. It's easy to build them, you don't need more than a few, you are expected to move any of the sliders or WB controls to produce a subjectively pleasing rendering you desire. You don't need an expensive target that's difficult to capture.
In terms of this new chart, in terms of the majority of photographers who don't deal with repro or scientific capture, anything else is well described by the last, great Bruce Fraser:
"You can do all sorts of things that are fiendishly clever, then fall in love with them because they're fiendishly clever, while overlooking the fact that they take a great deal more work to obtain results that stupid people get in half the time. As someone who has created a lot of fiendishly clever but ultimately useless techniques in his day, I'd say this sounds like an example."
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See this here on LuLa where I show some extremely large dEs in near whites depending on the surrounding colors. Fortunately, this problem doesn't occur in drum or transmission scanning. Camera/lens are subject to glare but this can be controlled and usually has a smaller effect.
https://forum.luminous-landscape.com/index.php?topic=124885.msg1049190#msg1049190
ok, thanks. I think it's the same issue I saw in my V750. I minimized that issue by cleaning the glass from the inside. Getting acces to the inside was not as easy, but once done it was definitely a big improvement.
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Josh is Michael’s son.
Oh, thanks for the info.
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You underestimate or do not understand photographers - inconsistency of the results is a nightmare and targets will give you precisely that in different lighting. Camera manufacturers, raw processing software vendors already use that approach to build pre-canned profiles for a set of lighting conditions. There are even commercially available solutions albeit not without their problems.
I haven't said any statement like 'you don't understand' or the like to anyone. So, I'm asking myself, why are you stating that to me? How can you be so sure about what I do or don't understand?
I have been teaching around 3,000 people in the last 20 years. About 300 of them are professionals, and I'm in contact with many, so I think I know them a bit...
"Normal" photographers in your definition would not waste time buying and shooting targets either. If and when they do, they then quite quickly become disillusioned in so called simplicity of this approach. Been there - done that and I am not even a pro(just a hobbyist).
Totally agree. They are not my target.
Tools like RawDigger give people control and understanding not complications.
I'm not saying Rawdigger is not a good tool. It indeed is. But just as a reference, of all the pros I know, barely 2-3 know and use it. That's less than 1%.
How to use what and results of what?
Your tool, of course.
Spectral sensitivity curves for cameras? Yes I did took some - they were quite close to published scientifically measured ones. They also fairly easily validated by taking shots of the measured colours in measured light and comparing to calculated camera response using spectral sensitivity curves.
So, can I see anything published? Or a tutorial on how to build and use it?
I don't understand the question about colorimetric analysis- if that is about accuracy of the profiles built from the known spectral sensitivity then nothing really stops you to tune profile calculation to any set of target colours as accurately as you need (recalculating the profile is a matter of running a software not reshooting a target, a new target under a new light).
Shooting targets correctly especially glossy ones is much more complicated that that.
Ok, so you mean with your tool you get the spectral curves of the camera that allows you to calculate the colorimetric appearance of any target given it's reference file with spectral data and the spectral curves of the lighting, right?
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Ok, so you mean with your tool you get the spectral curves of the camera that allows you to calculate the colorimetric appearance of any target given it's reference file with spectral data and the spectral curves of the lighting, right?
A primer for you:
http://dougkerr.net/Pumpkin/articles/Colorimetric_Characterization.pdf (http://dougkerr.net/Pumpkin/articles/Colorimetric_Characterization.pdf)
From the fellow you may ;D have mistaken for Bruce Fraser:
Building a perfect ICC profile for a digital camera viewing real
world scenes is only possible if the spectral response curves of the
camera happen to be an exact linear combination of the human eye's
cone response curves. Since there are no such cameras, perfect
digital camera profiles are impossible.
There are always going to be some objects that the camera "sees" to
be the same color, and the eye sees as different colors. A profile
cannot undo this data loss.
Thomas Knoll.
But just as a reference, of all the pros I know, barely 2-3 know and use it. That's less than 1%.
That speaks more about those you consider well educated pro photographers than anything else. :-[
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Acceptable profiles - yes. High quality - not in my experience. I did managed to get somewhat better results with QPCards in the past shooting them outdoors in lighting I needed (had CC passport at that time as well for comparison) - though that was 5-6 years ago.
Totally agree. acceptable or pleasant profiles are a thing. accurate and high quality is a different thing.
From my point of view, looking at how profiles are generated from all the targets (mathematically), these profiles will be tuned to accurately reproduce specific target colours and not anything else.
There are big differences in the accuracy of a profile depending on the number of patches (and that has been analyzed in some studies), and depending on the patch distribution. You'll get better accuracy where the chart has many patches concentrated in a particular area of the color map.
The superchroma has been designed so all the patches are at about dE 5 from the closest patches, so the distribution is uniform. I've seen charts with more than dE 30 (even more than dE60) from one patch to the closest, and that produces big errors.
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That speaks more about those you consider well educated pro photographers than anything else. :-[
Are you calling all them stupid or ignorant?
Oh, I see, you're the master and all the rest are stupid or ignorants. I get it.
You probably didn't notice but this your latest post showed everyone here what kind of person you're.
And, please, stop replying me. you waste your time.
Haven't you noticed yet that I stopped replying you, as I previously said?
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Are you calling all them stupid or ignorant?
Misinformed IF what you say about them is true. I have to wonder, without a tool like RawDigger, how they figure out how to expose for raw data.
You probably didn't notice but this your latest post showed everyone here what kind of person you're.
That's great news.
And, please, stop replying me. you waste your time.
Stop asking questions to the group OR learn to use the Ignore functions of this site.... ???
Haven't you noticed yet that I stopped replying you, as I previously said?
That appears to be another misconception of yours, since obviously to nearly anyone reading here, you JUST replied to me.
It's getting difficult to take you seriously again.
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By the way, would you trust someone that talks about himself as a master in camera profiling and recommends the following procedure for a good camera profiling?
1- take a photo with a 'good deal of colors' in RAW.
2- Get an untagged file from it (but don't explain how to get it). Very important!
3- Open it in Ps, and don't color manage.
4- open color settings.
5- Start playing with the profiles in the drop-down list, to see if any produces colors that 'you like best'. Don't forget to calibrate and profile your monitor!
6- If none of those work, just pick custom and start playing with everything there: primaries, gamma, WP...
7- Save that Frankenstein profile and you're done!
Andrew Rodney.
Creating camera profiles with Ps (http://www.digitaldog.net/files/CameraProfilinginPS.pdf)
:o
"Donde las dan las toman".
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By the way, would you trust someone that talks about himself as a master in camera profiling and recommends the following procedure for a good camera profiling?
Don't ask stupid questions about processes you don't understand or who they are directed towards**. :D
Don't lie to readers here stating you're going to ignore someone's posts and not reply, then reply two times within 10 minutes.
Don't post before and after pic's to sell a target whereby the pic's are bogus and don't represent what you're trying to SELL others.
Don't assume your arms are long enough to box with dog; they are not sir. ;)
Don't post another lie (I'd love to share and discuss technical details and the like with anyone interested here. I hope you find it interesting.), then decide what people have told you, isn't what you wanted them to say!
** EDIT: what you clearly don't understand and what you decided you needed to avoid posting and understanding was this important text outlined in the tutorial:
The following technique can be useful to people that have cameras whoʼs raw data is somewhat close to a standardized RGB Working Space. It can work for people who simply do not have the budget to buy special targets and camera profiling software or for those that are not happy with the results using profiling packages.
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Don't ask stupid questions about processes you don't understand or who they are directed towards. :D
There are no 'stupid questions', sir. It's just people that doesn't know that thing...I've always told that to my students. Well, it could be prepotent trainers also.
Don't lie to readers here stating you're going to ignore someone's posts and not reply, then reply two times within 10 minutes.
Don't think that is lying: it's making a last effort to show someone how wrong is him.
Don't post before and after pic's to sell a target whereby the pic's are bogus and don't represent what you're trying to SELL others.
Can you point me to one example of other brand showing examples of his chart and one of a competitor? Just one or two would be enough.
Don't post another lie (I'd love to share and discuss technical details and the like with anyone interested here. I hope you find it interesting.), then decide what people have told you, isn't what you wanted them to say!
Please do yourself a favour: read twice. I said I'd love to discuss with anyone, except those disrespectful people. A small detail you haven't read.
Read my replies and you'll see you're the only disrespectful. And even that, I haven't been disrespectful with you, and still I'm wasting my time here
BTW: You haven't refuted absolutely anything in my last post, which means you totally admit that. ;)
You took the tangent path in every of your replies. All OT, in few words.
Thanks. No more questions, sir.
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Thanks. No more questions, sir.
Promise honestly this time? Your track record hasn't been that great thus far.
Do ask yourself why, by and large, most people here are not taking you seriously?
I think Mark summed it up best (https://forum.luminous-landscape.com/index.php?topic=131216.msg1118328#msg1118328), then left the scene of your crime so to speak , a very good move on his part.
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ok, thanks. I think it's the same issue I saw in my V750. I minimized that issue by cleaning the glass from the inside. Getting acces to the inside was not as easy, but once done it was definitely a big improvement.
No. It's a completely different issue and effect than dirty glass. It's due to re-reflected light from the print being scanned to the white, adjacent strips that cover the LEDs. Contamination on the glass mostly alters (lightens) the dark colors.