Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: JayWPage on May 02, 2015, 01:33:33 am
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I am curious as to how the color gamut of my printer, the Epson 3880 compares to the color space of sRGB and Adobe RGB? I usually convert to Adobe RGB before printing but I really don't know if the gamut of this printer fits snugly within Adobe RGB or is it much smaller/inferior in some colors. I think this would be useful to know. Also how much will the gamut be affected by the type of paper printed on?
Thanks
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Hi,
Something like below on glossy paper.
Best regards
Erik
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Hi,
Matte papers have a smaller gamut see below. Smooth -> matte paper and wireframe ->glossy paper.
Best regards
Erik
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I am curious as to how the color gamut of my printer, the Epson 3880 compares to the color space of sRGB and Adobe RGB? I usually convert to Adobe RGB before printing but I really don't know if the gamut of this printer fits snugly within Adobe RGB or is it much smaller/inferior in some colors. I think this would be useful to know. Also how much will the gamut be affected by the type of paper printed on?
Thanks
As Erik shows, the fit is not "snug" because gamut shapes differ between device profiles and between those and colour working spaces. The 3880 is quite a wide-gamut printer. It is normally recommended that you work in ProPhoto RGB to be certain that all the colour the printer and your paper can reproduce will be available for it in your image file. The available gamut depends VERY heavily on the kind of paper you are using. On my Epson 4900 the gamut of a high quality luster paper exceeds that of any matte paper I've ever tested by a very large margin. If you want wide gamut use gloss or luster papers with Photo Black ink.
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...I usually convert to Adobe RGB before printing
What? Why would you convert from one space to another before printing?
Brian A
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Brian's question is well-taken. If the image file had been shrunk to sRGB in the first place and you do not have the raw file, you won't get more gamut converting it to another colour space.
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I am curious as to how the color gamut of my printer, the Epson 3880 compares to the color space of sRGB and Adobe RGB? I usually convert to Adobe RGB before printing but I really don't know if the gamut of this printer fits snugly within Adobe RGB or is it much smaller/inferior in some colors. I think this would be useful to know. Also how much will the gamut be affected by the type of paper printed on?
Neither working space is large enough for output to this printer! So here's how you can test this and see the results, ink on paper:
The benefits of wide gamut working spaces on printed output
This three part, 32 minute video covers why a wide gamut RGB working space like ProPhoto RGB can produce superior quality output to print.
Part 1 discusses how the supplied Gamut Test File was created and shows two prints output to an Epson 3880 using ProPhoto RGB and sRGB, how the deficiencies of sRGB gamut affects final output quality. Part 1 discusses what to look for on your own prints in terms of better color output. It also covers Photoshop’s Assign Profile command and how wide gamut spaces mishandled produce dull or over saturated colors due to user error.
Part 2 goes into detail about how to print two versions of the properly converted Gamut Test File file in Photoshop using Photoshop’s Print command to correctly setup the test files for output. It covers the Convert to Profile command for preparing test files for output to a lab.
Part 3 goes into color theory and illustrates why a wide gamut space produces not only move vibrant and saturated color but detail and color separation compared to a small gamut working space like sRGB.
High Resolution Video: http://digitaldog.net/files/WideGamutPrintVideo.mov
Low Resolution (YouTube): https://www.youtube.com/watch?v=vLlr7wpAZKs&feature=youtu.be
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Hi Andrew, I've watched this video previously and I think it is definitive.
I have, however, one directly relevant question for you related to the points above about where one starts with working spaces. I suspect the OP may be using photos that are now in "raw" format, but already converted to sRGB either in his camera or application. In this situation is it not the case that having lost all that gamut between raw and sRGB, his options are limited and he will not get any gamut benefit trying to convert a baked sRGB file into a wider colour space?
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What? Why would you convert from one space to another before printing?
Brian A
I usually open my raw files in ProPhoto RGb in ACR and continue working in this color space until I am finished doing whatever i think is necessary. Then I create a printing file with whatever size, output sharpening, etc. and I then convert to Adobe RGB so that I can see which conversion looks best (perceptual or RC) and to see if there are any out of gamut colors.
I always take both raw and jpeg images, but the jpegs are just to allow for easy editing or maybe to email to someone while traveling, I never work with them.
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I usually open my raw files in ProPhoto RGb in ACR and continue working in this color space until I am finished doing whatever i think is necessary. Then I create a printing file with whatever size, output sharpening, etc. and I then convert to Adobe RGB so that I can see which conversion looks best (perceptual or RC) and to see if there are any out of gamut colors.
I always take both raw and jpeg images, but the jpegs are just to allow for easy editing or maybe to email to someone while traveling, I never work with them.
In this case I recommend that you stick with the ProPhoto space right through from ingestion to Print. Forget about RGB(98).
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I believe all color space conversions are made in RC....no matter what you select.
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I can see from Erik's plots that I am loosing some of the blue green area by converting, so I will be better off staying in ProPhoto RGB.
I don't understand what you mean when you say "I believe all color space conversions are made in RC", can you explain.
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Hi Andrew, I've watched this video previously and I think it is definitive.
Thanks.
I have, however, one directly relevant question for you related to the points above about where one starts with working spaces. I suspect the OP may be using photos that are now in "raw" format, but already converted to sRGB either in his camera or application.
I was just hoping to answer the initial question without regard to the workflow. It appears that since that post, the OP has written he works in ProPhoto RGB then converts to Adobe RGB for print. We both agree that's pointless.
As to the other questions about rendering intents with the supplied working space profiles. All conversions using simple matrix working space profiles, those found in Photoshop use RelCol for conversions. There is no perceptual table in those installed working space profiles. You can pick Perceptual in Photoshop, you'll get RelCol.
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So what you are telling me is that if my image is in ProPhoto RGB and I print having PS manage the colors, that regardless whether I choose perceptual or RC, the colours outside the Epson 3880 (or whatever printer you have) gamut will be clipped to the nearest printable color that the printer is capable of printing on that particular paper?
I had thought that gamut compression using perceptual conversion was done through some sort of vector calculation. What role does the paper profile have in determining where the colors are clipped? I print through ImagePrint V9, it's been my impression that when I select a perceptual rendering intent in ImagePrint that it was perceptual, not RC.
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So what you are telling me is that if my image is in ProPhoto RGB and I print having PS manage the colors, that regardless whether I choose perceptual or RC, the colours outside the Epson 3880 (or whatever printer you have) gamut will be clipped to the nearest printable color that the printer is capable of printing on that particular paper?
RGB working space to working space (matrix profiles) always uses RelCol. ProPhoto RGB to a printer profile can use any of the three tables that exist in that printer profile.
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So what you are telling me is that if my image is in ProPhoto RGB and I print ..... regardless whether I choose perceptual or RC, the colours outside the Epson 3880 (or whatever printer you have) gamut will be clipped to the nearest printable color that the printer is capable of printing on that particular paper?
Think about what you've written a little. How could a printer not clip what it can't print ?
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How could a printer not clip what it can't print ?
The subject is about how out of gamut colors from a large color space (ProPhoto RGB) are converted to a smaller color space (that of the Epson 3880). The question is are they clipped to the edge of the Epson 3880 color space (relative colorimetric) or are they scaled to some relative color within the Epson space (perceptual).
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The question is are they clipped to the edge of the Epson 3880 color space (relative colorimetric) or are they scaled to some relative color within the Epson space (perceptual).
Either, depending on what you select in the app doing the printing. If you have no control, it's probably Perceptual but that can be set when the profile is built.
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The subject is about how out of gamut colors from a large color space (ProPhoto RGB) are converted to a smaller color space (that of the Epson 3880). The question is are they clipped to the edge of the Epson 3880 color space (relative colorimetric) or are they scaled to some relative color within the Epson space (perceptual).
u
Although the out--of-gamut mapping in both Lr and Ps isn't that accurate, it still gives you some chance of deciding what intent to chose. If there are no out-of-gamut colors in the image, then relative colorimetric would be the first choice. If there are out-of-gamut colors in large areas of the image, then you can make a decision on whether to use perceptual or relative colorimetric.
In either case, you may find one intent more pleasing than the other. There is nothing set in stone about artistic choice.
Brian A
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So what you are telling me is that if my image is in ProPhoto RGB and I print having PS manage the colors, that regardless whether I choose perceptual or RC, the colours outside the Epson 3880 (or whatever printer you have) gamut will be clipped to the nearest printable color that the printer is capable of printing on that particular paper?
Here is what happens. The first chart is a plot of all colors in the attached image of my daughter in ProPhoto RGB. The second chart shows shows the colors after the image was converted to sRGB (uses Relative Colorimetric). The third was converted from ProPhoto to the color space of Epson 3880 with a glossy paper using Perceptual intent.
The triangles in the charts represent sRGB and ProPhoto RGB.
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If you have a Mac then open the Colorsync utility and you can display each profile (AdobeRGB, printer profiles etc) and twirl them around to see them from every angle.
I don't get what you mean by "The question is are they clipped to the edge of the Epson 3880 color space (relative colorimetric) or are they scaled to some relative color within the Epson space (perceptual)". Unless I am missing something that firstly depends on whether you select relative or perceptual in the rendering intent. Relative calorimetric means that only the out of gamut colours are scaled. Perceptual means that ALL colours are scaled.
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Although the out--of-gamut mapping in both Lr and Ps isn't that accurate, ...........There is nothing set in stone about artistic choice.
Brian A
Yes, I agree - it's a matter of taste and what in the photographer's vision best suits the photo.
However, I don't understand what you mean by the statement that the gamut mapping in LR/PS "isn't that accurate". How would you define "accurate gamut mapping" and how do you know relative to such standard that these applications are performing inaccurately?
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However, I don't understand what you mean by the statement that the gamut mapping in LR/PS "isn't that accurate".
Note that accurate gamut mapping must take into account the gamut of the input. (sounds obvious, but...)
By the very way that most ICC profiles are built, this can't be the case, since the profiling software has no mechanism to be told what the input gamut is going to be - the profiling software will assume some generic source gamut and/or generic gamut mapping, which won't be tailored to the gamut you actually have.
The process of achieving accurate gamut mapping in large gamut spaces has problems too - unlike smaller spaces such as sRGB or AdobeRGB, you can't just assume that the colorspace gamut is representative of the gamut you value in the image.
Accurate gamut mapping is achievable, but the workflow and tools have to be a little different...
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However, I don't understand what you mean by the statement that the gamut mapping in LR/PS "isn't that accurate". How would you define "accurate gamut mapping" and how do you know relative to such standard that these applications are performing inaccurately?
It shows you an overlay for colors that are not OOG! I'd call that inaccurate Mark!
It's also unnecessary and useless in the form it's provided on top of being inaccurate.
How is blocking your image with an ugly overlay any better than viewing the effect of the soft proof and various rendering intents?
How is blocking your image with an ugly overlay that treats all OOG colors the same useful, what are you supposed to do now? Manually make them disappear? Bad idea.
OOG in Adobe products was fine before 1998 and ICC color management in Photoshop. It's not today.
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Note that accurate gamut mapping must take into account the gamut of the input. (sounds obvious, but...)
By the very way that most ICC profiles are built, this can't be the case, since the profiling software has no mechanism to be told what the input gamut is going to be - the profiling software will assume some generic source gamut and/or generic gamut mapping, which won't be tailored to the gamut you actually have.
Sounds reasonable
The process of achieving accurate gamut mapping in large gamut spaces has problems too - unlike smaller spaces such as sRGB or AdobeRGB, you can't just assume that the colorspace gamut is representative of the gamut you value in the image.
Not sure that I am getting this. If (e.g.) pro photo RGB is a superset of all practical input/output devices, and at the same time the numerical representation is such that quantization is no problem, then representing an image in that format together with output device profile ought to give the rendering application the (best available) knowledge about:
1) The color of the scene
2) The color abilities of an output device
What can be achieved by telling the output module about the gamut limits of the acquisition device? So I know that rgb[258,257,256] may in fact correspond to any value in an out-of-gamut volume that has been clipped. If the clipped number is the closest mapping, it still seems to make sense to use that value (outside of speculative gamut recovery)?
Accurate gamut mapping is achievable, but the workflow and tools have to be a little different...
Me think that "accurate" color is asymptotically hard/expensive to achieve and seldom 100% anyways. So for many of us (non-museum archivists) it may be a matter of getting "close enough" while having the resources to do the things that we set out to do in the first place.
-h
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It shows you an overlay for colors that are not OOG! I'd call that inaccurate Mark!
It's also unnecessary and useless in the form it's provided on top of being inaccurate.
How is blocking your image with an ugly overlay any better than viewing the effect of the soft proof and various rendering intents?
How is blocking your image with an ugly overlay that treats all OOG colors the same useful, what are you supposed to do now? Manually make them disappear? Bad idea.
OOG in Adobe products was fine before 1998 and ICC color management in Photoshop. It's not today.
When I read Brian's statement I thought he was making a more general mathematical observation and not so much a judgment on the usefulness of the IG/OOG toggle in Photoshop, which does have the limitations you mention here. BTW, however, despite its limitations it's not useless for making comparisons between profiles reflecting different paper/printer combinations - it can be comparatively indicative - helpful to visualizing differences. But that kind of stuff I think is not what Brian's statement is all about - let us await his clarification.
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BTW, however, despite its limitations it's not useless for making comparisons between profiles reflecting different paper/printer combinations - it can be comparatively indicative - helpful to visualizing differences.
I have much better software tools to do that. ColorThink Pro for one.
The function is supposed to be useful for image editing, it isn't.
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Yes I also have ColorThink Pro and think it is excellent for what it does - essentially profile analysis. If you want to see the impact of relative gamut limitations on real photographs, this is not the tool for that. And I agree, I would not use Photoshop's gamut overlay tool for photo editing. The softproofing one however is very useful.
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Yes I also have ColorThink Pro and think it is excellent for what it does - essentially profile analysis. If you want to see the impact of relative gamut limitations on real photographs, this is not the tool for that.
I disagree. One can sample down images and plot them in 3D within CT Pro. One can build color lists from that data. It's far more useful to understand the image gamut compared to any other gamut than anything in Photoshop.
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Ah - OK - are you referring to the Color Worksheet tool? Normally I haven't been using this application for that functionality, but what you are saying looks attractive for exacting work.
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Yes, I agree - it's a matter of taste and what in the photographer's vision best suits the photo.
However, I don't understand what you mean by the statement that the gamut mapping in LR/PS "isn't that accurate". How would you define "accurate gamut mapping" and how do you know relative to such standard that these applications are performing inaccurately?
I have had images that when exported from Lightroom in one space, and then soft proofed using that space profile, have shown out-of-gamut colors. Something not quite right there.
Brian A
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I have had images that when exported from Lightroom in one space, and then soft proofed using that space profile, have shown out-of-gamut colors. Something not quite right there.
Brian A
Strange, I have not come across that problem - not saying it can't happen, but are you quite certain that before the file left LR all the colours (not only the luminance) were in-gamut for the embedded profile?
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Strange, I have not come across that problem - not saying it can't happen, but are you quite certain that before the file left LR all the colours (not only the luminance) were in-gamut for the embedded profile?
I haven't tried it in a while, but export from edited raw to sRGB jpeg. Then viewed the jpeg in Lr and the soft proof showed out-of-gamut colors using the sRGB profile.
Brian A
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I haven't tried it in a while, but export from edited raw to sRGB jpeg. Then viewed the jpeg in Lr and the soft proof showed out-of-gamut colors using the sRGB profile.
Brian A
Assuming when you edited the raw file to the sRGB color space before exporting LR was not showing any OOG colour, I'm wondering whether this happened because of JPEG compression.
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If (e.g.) pro photo RGB is a superset of all practical input/output devices, and at the same time the numerical representation is such that quantization is no problem, then representing an image in that format together with output device profile ought to give the rendering application the (best available) knowledge about:
1) The color of the scene
2) The color abilities of an output device
Right, but if the rendering to the printer gamut takes proPhoto as the source gamut, then the output will very likely not be pleasing, since you are squashing the very large gamut down to the printer gamut, taking your image with it.
If the profile has a very generic gamut mapping then this problem is avoided, but you also don't get to keep anything outside that generic gamut mapping, rather reducing the benefits of having your images stored in a large gamut space.
Of course you can manually reduce the gamut of your image into the printer space using an image editing package, and use relative colorimetric when printing it, but that's going to require a good deal more effort for each and every image.
What can be achieved by telling the output module about the gamut limits of the acquisition device?
I don't know - why would you want to do that ?
So I know that rgb[258,257,256] may in fact correspond to any value in an out-of-gamut volume that has been clipped. If the clipped number is the closest mapping, it still seems to make sense to use that value (outside of speculative gamut recovery)?
Sorry, I'm not following you. While technically clipping is a form of gamut mapping, gamut mapping is typically of interest when applied to achieving perceptually pleasing results, by compressing the gamut so as to trade absolute color accuracy in return for maintaining the distinction between different colors in the original image.
Me think that "accurate" color is asymptotically hard/expensive to achieve and seldom 100% anyways.
The original comment was about accurate gamut mapping, not accurate color reproduction.
Loss of accuracy can occur and many stages. One of them is in the maths/code used to implement gamut mapping, but also in the workflow chosen in making use of gamut mapping.
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I have had images that when exported from Lightroom in one space, and then soft proofed using that space profile, have shown out-of-gamut colors. Something not quite right there.
That's nothing to do with gamut mapping though. Seems more to do with the out of gamut warning calculations, since (by definition) an image stored in a particular device space can't be outside that device space.
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That's nothing to do with gamut mapping though. Seems more to do with the out of gamut warning calculations, since (by definition) an image stored in a particular device space can't be outside that device space.
Exactly!
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Right, but if the rendering to the printer gamut takes proPhoto as the source gamut, then the output will very likely not be pleasing, since you are squashing the very large gamut down to the printer gamut, taking your image with it.
Is that not what I am doing in Lightroom, working in proPhoto, softproofing using a measured profile of my 3880/paper combo, tweaking until I am pleased, then pressing "print"?
If the profile has a very generic gamut mapping then this problem is avoided, but you also don't get to keep anything outside that generic gamut mapping, rather reducing the benefits of having your images stored in a large gamut space.
Of course you can manually reduce the gamut of your image into the printer space using an image editing package, and use relative colorimetric when printing it, but that's going to require a good deal more effort for each and every image.
I don't know - why would you want to do that ?
I believe that I was referring to your statement: "Note that accurate gamut mapping must take into account the gamut of the input. ". This appears to mean that input gamut has to be considered. I can't understand why that is a requirement if (rather) one can represent the image using a "super-gamut" (proPhoto?), then map that gamut to any desired output gamut?
Sorry, I'm not following you. While technically clipping is a form of gamut mapping, gamut mapping is typically of interest when applied to achieving perceptually pleasing results, by compressing the gamut so as to trade absolute color accuracy in return for maintaining the distinction between different colors in the original image.
Lightroom offers the "perceptual" vs "relative" intent. I was under the impression that these were automated "soft clipping" vs "hard clipping" of gamut, while soft-proofing allowed me to manually navigate within those limits.
I think that it is strange that (apparently) color choices are made by my paper (profile) supplier, my display calibrator/profiler software and my camera profile software. Would it not make more sense for all of these to rather provide objective/passive information about the devices capabilities, then (e.g.) Adobe could hire one more color scientist or two doing optimal mappings (with or without manual intervention), as the raw image editor is the hub that has access to most information and the natural place to ask the user about preferences?
-h
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Is that not what I am doing in Lightroom, working in proPhoto, softproofing using a measured profile of my 3880/paper combo, tweaking until I am pleased, then pressing "print"?
Probably not - because you haven't mentioned creating a device link or ICC profile with a gamut mapping tailored specifically to your source space or images. I'd guess you are using the generic gamut mapping created by whatever software created the ICC profiles you are using.
I believe that I was referring to your statement: "Note that accurate gamut mapping must take into account the gamut of the input. ". This appears to mean that input gamut has to be considered. I can't understand why that is a requirement if (rather) one can represent the image using a "super-gamut" (proPhoto?), then map that gamut to any desired output gamut?
It's a requirement from the definition of (real) gamut mapping - mapping one gamut into another. That implies two gamuts, a source and a destination, if the mapping is going to be accurate in this task. As I was alluding to, while you can get away with assuming your images completely fill a smaller gamut space like sRGB or AdobeRGB, assuming this with a large gamut space (like ProPhoto, scRGB, L*a*b* etc.) will give extreme compression, and it probably won't look very good if mapped to your printer space.
I think that it is strange that (apparently) color choices are made by my paper (profile) supplier, my display calibrator/profiler software and my camera profile software. Would it not make more sense for all of these to rather provide objective/passive information about the devices capabilities, then (e.g.) Adobe could hire one more color scientist or two doing optimal mappings (with or without manual intervention), as the raw image editor is the hub that has access to most information and the natural place to ask the user about preferences?
Makes sense to me. But that's not how things have evolved. Under the pressure of people demanding that "it just work", everyone in the chain has tried to make things look "really nice" without needing to judge or adjust or choose anything.
I generally roll my eyes when I come across yet another technical article about how to identify and then automatically tweak "key memory colors" like sky, grass, skin etc. in images to make the result "more pleasing". But then this sort of tweaking has gone on forever - none of the photographic processes reproduced color faithfully, they all tweaked it (using chemical "algorithms") to enhance saturation, contrast etc. etc. so that people liked what they saw, and make it better corresponded to what they remembered. Much of the digital workflow has emulated all that.
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That's nothing to do with gamut mapping though. Seems more to do with the out of gamut warning calculations, since (by definition) an image stored in a particular device space can't be outside that device space.
Well call it a calculation/function/mapping/transformation, my point was that the out-of-gamut warning wasn't always accurate. But I still find it useful for comparing profiles before printing.
Brian A
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I generally roll my eyes when I come across yet another technical article about how to identify and then automatically tweak "key memory colors" like sky, grass, skin etc. in images to make the result "more pleasing". But then this sort of tweaking has gone on forever - none of the photographic processes reproduced color faithfully, they all tweaked it (using chemical "algorithms") to enhance saturation, contrast etc. etc. so that people liked what they saw, and make it better corresponded to what they remembered. Much of the digital workflow has emulated all that.
In the final analysis photographers, unless they are practicing forensic, scientific or commercial photography where "colour accuracy" may matter, generally want their photographs to suit artistic purposes for which faithful colour reproduction may be either a rather low priority or even irrelevant. Processes aren't ends in their own right - they are a means to an end and the ends will differ depending.
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I believe all color space conversions are made in RC....no matter what you select.
Yes for the monitor, but you can soft proof or do what I do, let the Epson give you perceptual and make a few prints til it's right.
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Probably not - because you haven't mentioned creating a device link or ICC profile with a gamut mapping tailored specifically to your source space or images. I'd guess you are using the generic gamut mapping created by whatever software created the ICC profiles you are using.
*I have profiled my camera using a colorchecker Passport/xRite software and a couple of different illuminations.
*I semi-periodically profile/calibrate my displays using the xRite i1 display pro and i1 profiler software
*I download printer profiles for my 3880 from my paper suppliers.
*I print from Adobe Lightroom after using softproofing.
All of these assume that the color characteristics of my devices are of a somewhat static nature (measure in one or a few cases, reuse afterwards).
It's a requirement from the definition of (real) gamut mapping - mapping one gamut into another. That implies two gamuts, a source and a destination, if the mapping is going to be accurate in this task. As I was alluding to, while you can get away with assuming your images completely fill a smaller gamut space like sRGB or AdobeRGB, assuming this with a large gamut space (like ProPhoto, scRGB, L*a*b* etc.) will give extreme compression, and it probably won't look very good if mapped to your printer space.
So if what I am doing (which seems to be a pretty common normal way of doing things) is not (real) gamut mapping, then what am I doing, and what am I missing? If a patch of an image is numerically represented as rgb [12,42,255] and the camera profile describe how the camera maps (perceptual-models of) color to 3-channel readings and the display/printer profile describes how the (post calibration) display/printer maps 3-channel input to (perceptual-models-of) color, then what is left?
Makes sense to me. But that's not how things have evolved. Under the pressure of people demanding that "it just work", everyone in the chain has tried to make things look "really nice" without needing to judge or adjust or choose anything.
I always thought that sRGB was the "always just works" method, and that color management was an attempt to make things "right" at the expense of endless hair-pulling.
I generally roll my eyes when I come across yet another technical article about how to identify and then automatically tweak "key memory colors" like sky, grass, skin etc. in images to make the result "more pleasing". But then this sort of tweaking has gone on forever - none of the photographic processes reproduced color faithfully, they all tweaked it (using chemical "algorithms") to enhance saturation, contrast etc. etc. so that people liked what they saw, and make it better corresponded to what they remembered. Much of the digital workflow has emulated all that.
I want my pipeline to be able to do perceptually transparent reproductions of reality (or as much so as 2-d static technology and my time/economy allows). Then I take the liberty to bluntly ignore the "scientifically correct" answer whenever I feel like it based on my conscious choice, not some faceless product developer.
-h
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I always thought that sRGB was the "always just works" method, .................
-h
Actually, if we are talking about today's professional inkjet printers you can be sure that sRGB will be the "always DOES NOT work method" because it's colour space is far too narrow relative to the colour reproduction capabilities of these printers. It is safest to use ProPhoto as your colour working space and softproof to your printer profile. I expect you know this, so I'm wondering what you meant by that comment.
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Well call it a calculation/function/mapping/transformation, ..
Conflating related but different terms together, doesn't make for clear communications.
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In the final analysis photographers, unless they are practicing forensic, scientific or commercial photography where "colour accuracy" may matter, generally want their photographs to suit artistic purposes for which faithful colour reproduction may be either a rather low priority or even irrelevant. Processes aren't ends in their own right - they are a means to an end and the ends will differ depending.
Sure, and this works well if it's a closed loop processes, where one party (i.e. Kodak, Fuji) has made it all work.
But in the modern world where photography has many players in the chain, it doesn't work so well when each player adds their own "special subjective sauce" to the mix. To untangle it all requires a clear understanding of each step in the chain, preferably with just a single step where the subjective/artistic manipulations take place, either automatically or under control of the user, with all the other steps striving for faithful color reproduction.
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So if what I am doing (which seems to be a pretty common normal way of doing things) is not (real) gamut mapping, then what am I doing, and what am I missing?
You are relying on the generic (i.e. not specific to the gamut you want to reproduce) gamut mapping/clipping in your printer profiles. Your paper suppliers certainly don't know what your image colorspaces are, nor what gamut your images occupy out of that space.
If a patch of an image is numerically represented as rgb [12,42,255] and the camera profile describe how the camera maps (perceptual-models of) color to 3-channel readings and the display/printer profile describes how the (post calibration) display/printer maps 3-channel input to (perceptual-models-of) color, then what is left?
Making one fit into the other (i.e. gamut mapping (http://www.argyllcms.com/gammutmapping.x3d.html)).
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Sure, and this works well if it's a closed loop processes, where one party (i.e. Kodak, Fuji) has made it all work.
But in the modern world where photography has many players in the chain, it doesn't work so well when each player adds their own "special subjective sauce" to the mix. To untangle it all requires a clear understanding of each step in the chain, preferably with just a single step where the subjective/artistic manipulations take place, either automatically or under control of the user, with all the other steps striving for faithful color reproduction.
Yes, put in that way it makes sense.
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Hi. First, Thank you to all the contributors to this post. It was very educational and I found out why I was having problems with some colors when printing on my 3880. I went back to the original Raw files set Camera Raw to Prophoto rgb then printed our a sample print on art paper. Also printed a sample of the same original raw file but using Adobe RGB. What a difference. My other half who is a working artist and uses very vibrant colors asked why I had not done this before. Her prints just popped out. and the details could now be seen etc.... I did not make any other changes to the settings in Camera Raw....
Background: I am a one trick pony and only work with original art/paintings etc. No photographs of lakes, mountains etc etc. Only Original Art.
I then ran a test with some of the standard traditional paintings from the lake district in England. Paintings of scenes in Ontario, Terra Cotta up to Georgian Bay. There was no obvious difference in the results when comparing Prophoto to AdobeRGB. (all using the original Raw data). So it seems that only where you have very vibrant scenes may Prophoto rgb be of visible benefit.
Therefore while I will now use Prophoto all the time, I think I know when it will enhance the results.
One Question -- Camera Calibration? when shooting a sample of my Color Checker Passport, I check it out in Camera Raw to see if light is ok etc...
Then I save the image in DNG and go in to create my camera Profile.
Will the use of the Prophoto have any effect on this process. That is will all the patches be within the adobe rgb gamut only??
Thank you Elo
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So here's how you can test this and see the results, ink on paper:
High Resolution Video: http://digitaldog.net/files/WideGamutPrintVideo.mov
Low Resolution (YouTube): https://www.youtube.com/watch?v=vLlr7wpAZKs&feature=youtu.be[/i]
Thanks. That was a very effective demonstration.