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Author Topic: Color management myths and misinformation video  (Read 77769 times)

hugowolf

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Re: Color management myths and misinformation video
« Reply #220 on: September 01, 2014, 11:52:54 pm »

You've told me my Epson printer has a larger color gamut than sRGB.  Why do I like the way it looks on my sRGB display, more than my print?  

The printer in question may well have a larger gamut than sRGB, but there is still a lot of sRGB that your printer cannot reproduce. The printer gamut does not contain the sRGB gamut.

And yes, it could also have a lot to do the reflective vs transmisive, especially if you are used to working in the motion picture industry.

Brian A
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smthopr

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Re: Color management myths and misinformation video
« Reply #221 on: September 02, 2014, 12:07:54 am »

The printer in question may well have a larger gamut than sRGB, but there is still a lot of sRGB that your printer cannot reproduce. The printer gamut does not contain the sRGB gamut.

And yes, it could also have a lot to do the reflective vs transmisive, especially if you are used to working in the motion picture industry.

Brian A

That is exactly right Brian.  And that brings us back to the idea of large vs small color space. 

Suppose I'm just starting to learn this stuff.  People are telling me that I need to work in a large space because my printer is "larger" than sRGB, but now you're telling me that it is, and , it isn't?  Very, very confusing.

And what I'm getting at, what Brian is alluding to, is that some parts of the color gamut are way more important than others.  Not just a matter of large vs. small.

Better I think to use Venn Diagrams to show the relative size of spaces and their INTERSECTIONS to explain the color management idea.

And now, how do we make a good print on matte paper with a very small gamut?  It's not automatic.  That's where the craft comes in.  Not just rendering intents, though they may be useful sometimes.
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GWGill

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Re: Color management myths and misinformation video
« Reply #222 on: September 02, 2014, 01:41:31 am »

Agreed, but maybe worth restating: everything in CIE colorimetry, including ∆E values, is based on judging color matches in a very controlled and artificial environment. If you take a look at the Beau Lotto image on page 9 of this thread, you'll see an example of two very different "colors" with a ∆E of precisely zero. These tools are too blunt for asking nuanced questions like how many individual colors are in a real-world image if by 'color' we mean something other than a number.
Use the right tool for the job. CIE colorimetry doesn't attempt to model spatial visual appearance. If you want to do that you need to look at refinements of CIE such as retinex, iCam, etc.

But that's not terribly relevant to the business of reproducing images. If each corresponding pixel of two images matches according to CIE and they are viewed under comparable conditions, then the two images are going look very, very similar.
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Tony Jay

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Re: Color management myths and misinformation video
« Reply #223 on: September 02, 2014, 04:19:44 am »

Yup!

And then, I'm thinking here of the whole issue of luminance levels, or ranges.  Color spaces seem to assume fixed luminance ranges. Doesn't this effect the color gamut as well?  It's an interesting limitation to the "color space" concept.

I can squeeze my 16 stop Dynamic Range from my camera into any display range by showing a low-contrast image.  But what happens with the mapping of colors that we see in this low contrast image.  When we add an "s" curve to cram that into the display, or print, what happens to the color?

What I mean is that now we are dealing very much with perception.  And the whole idea that this is all kind of "automated" as long as one uses color management, is not really true.  Since we are thinking about how to explain this stuff to the novices, then I think, we should just forget about it. That's why it takes an "artist" to make a good print.  Even with a "soft proof", it still takes the interpretation of the artist to make the color space jumps successful.
It isn't even "not really true", it is absolutely untrue!
The concept of just ticking the softproofing option in Lightroom and "accepting" the result is complete anathema to a good understanding of colour management.
The problem is that one is actually not "doing " anything.
Ticking the softproofing button has been eloquently described as the "how to make my image look like cr@p button".
If no action is taken to make the image not look like cr@p then it will still look like cr@p when printed.
Usually some attention to contrast and perhaps some tweaks to colour may be necessary to get the proof copy to resemble as closely as possible the master.
The bottom line is that none of this happens by default.

It is true that it takes some aesthetic ability to get a good master.
It takes extra work to get the proof copy right.
Even then with an excellent ICC printer/paper profile it also takes some time to get used to the characteristics of both paper and printer to get the best out of them.

As for the characteristics of RGB colourspaces it is true that changing luminance affects chroma directly.
In Photoshop, at least, one can make adjustments in Lab if required since using Lab allows luminance or tone to be adjusted independently of hue at least. (the "L" stands for luminance, while "a" and "b" are the other axes that control hue).
Most of us, I think, would not bother to do that unless what we were doing was absolutely colour critical.

Again, I humbly apologise if all of this is known to you, but it may help those still trying to get to grips with the actual process of softproofing.

Tony Jay
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sandymc

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Re: Color management myths and misinformation video
« Reply #224 on: September 02, 2014, 05:51:33 am »

Yes there is - distance in device independent space (ie. a colorspace directly related to what we see).
For a measure that can be compared in significance, using a perceptually uniform space is even better.
Hence the use of delta E as a measure of gamut size.Not at all. We don't measure the distance between things by seeing how many 1 meter (or 1 foot) rulers we can lay end to end, beyond elementary school. At some stage in our education we are introduced to real numbers rather than simple counting. So it is with measuring colorspaces.

Not even on this forum, which is color geek heaven, have I ever seen anyone actually quote the size of a color space in any units. Now I may have missed an occasion or two, but I really don't think there is a non-geek measure.

BTW, delta E is not a measure of gamut size, it is the measure of the difference between two points in color space. Aka, it the length of a line, not an area. http://en.wikipedia.org/wiki/Color_difference

Sandy
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Tony Jay

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Re: Color management myths and misinformation video
« Reply #225 on: September 02, 2014, 06:07:55 am »

...BTW, delta E is not a measure of gamut size, it is the measure of the difference between two points in color space. Aka, it the length of a line, not an area. http://en.wikipedia.org/wiki/Color_difference...
Correct.

Tony Jay
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GWGill

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Re: Color management myths and misinformation video
« Reply #226 on: September 02, 2014, 10:32:14 am »

Not even on this forum, which is color geek heaven, have I ever seen anyone actually quote the size of a color space in any units.
The first posting in this thread, point 4:
http://www.luminous-landscape.com/forum/index.php?topic=93004.msg757129#msg757129
The prior thread:
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756292#msg756292
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756299#msg756299
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756379#msg756379
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756381#msg756381
etc.
And there are ArgyllCMS tools too, that compute gamut volume, as well as intersecting volumes.

(And I'd hardly call this forum "color geek heaven" - it's not that much fun.)

Quote
BTW, delta E is not a measure of gamut size, it is the measure of the difference between two points in color space. Aka, it the length of a line, not an area. http://en.wikipedia.org/wiki/Color_difference
If delta E is a distance measure, then naturally you measure gamut volume in delta E cubed.
« Last Edit: September 02, 2014, 07:42:52 pm by GWGill »
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digitaldog

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Re: Color management myths and misinformation video
« Reply #227 on: September 02, 2014, 10:39:18 am »

The first posting in this thread, point 4:
http://www.luminous-landscape.com/forum/index.php?topic=93004.msg757129#msg757129
The prior thread:
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756292#msg756292
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756299#msg756299
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756379#msg756379
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756381#msg756381
etc.
And there are ArgyllCMS tools too, that compute gamut volume, as well as intersecting volumes.

(And I'd hardly call this forum "color geek heaven" - it's not that much fun.)
If delta E is a linear measure, then naturally you measure gamut volume in delta E cubed.

Graeme is correct, we've discussed a metric for gamut size (Gamut Volume) as reported by ColorThink a few times and I believe we came up with the conclusion it has nothing to do with the 'number of colors' of which this thread has discussed in great length. CT reports Adobe RGB having a larger gamut volume than sRGB and when you view the volume of both, that kind of makes sense. Extrapolating this to mean it has more colors was if I understand all points from the so called color geek heaven posters, dismissed.
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digitaldog

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Re: Color management myths and misinformation video
« Reply #228 on: September 02, 2014, 10:53:08 am »

You're making a mountain out of a molehill.
I want to go back to this discussion for smthopr because it rises an important additional point a video could raise. That being a wide gamut editing space is an issue because you can't see all the colors. As I pointed out to him, you have to decide if you want to contain and use colors you can't see or clip them so you can see them all.
Here is an analysis from ColorThink. I start with a raw image of a colorful flower and encode into ProPhoto RGB. I then convert a copy to the display profile for my MacBook (I could use sRGB or even my wide gamut display but figured this is a good start). ColorThink provides a deltaE report in two ways. For smthopr, the one right of the two images is most important for someone working visually. Anything green is less than 1dE, so it's totally moot. The yellow is a dE higher than 1 but lower than 6. Here you can see what you can't see <g> on the display. Not much that would produce IMHO, issues editing this image! Lastly is the dE list of each pixel, all 62400 of them. Two pixels are over a dE of 6 and are shown in orange. All the others which are the yellow OOG colors in ProPhoto are at worst (from bottom to top) 5.94. Notice not all of the high dE colors are the bright yellow of the flower but some are darker but saturated colors. But the real important view in context of this discussion is the dE 'image map' if I can call it that. All that green that you'd be working with is visisble on your sRGB-like display.

Here's the actual screen capture if you want to view it larger: http://digitaldog.net/files/ProPhotoVsDisplayGamut.jpg

So yes, I think when people dismiss wide gamut working spaces to suggest 'there's no ProPhoto RGB displays' they are making a mountain out of a molehill. Just keep a steady hand on Vibrance and Saturation controls and don't keep moving them if you don't see any update on-screen. Danger Will Robinson, Danger.
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smthopr

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Re: Color management myths and misinformation video
« Reply #229 on: September 02, 2014, 11:04:06 am »

It isn't even "not really true", it is absolutely untrue!
The concept of just ticking the softproofing option in Lightroom and "accepting" the result is complete anathema to a good understanding of colour management.
The problem is that one is actually not "doing " anything.
Ticking the softproofing button has been eloquently described as the "how to make my image look like cr@p button".
If no action is taken to make the image not look like cr@p then it will still look like cr@p when printed.
Usually some attention to contrast and perhaps some tweaks to colour may be necessary to get the proof copy to resemble as closely as possible the master.
The bottom line is that none of this happens by default.

It is true that it takes some aesthetic ability to get a good master.
It takes extra work to get the proof copy right.
Even then with an excellent ICC printer/paper profile it also takes some time to get used to the characteristics of both paper and printer to get the best out of them.

As for the characteristics of RGB colourspaces it is true that changing luminance affects chroma directly.
In Photoshop, at least, one can make adjustments in Lab if required since using Lab allows luminance or tone to be adjusted independently of hue at least. (the "L" stands for luminance, while "a" and "b" are the other axes that control hue).
Most of us, I think, would not bother to do that unless what we were doing was absolutely colour critical.

Again, I humbly apologize if all of this is known to you, but it may help those still trying to get to grips with the actual process of softproofing.

Tony Jay

Thanks Tony.  Well said.

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sandymc

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Re: Color management myths and misinformation video
« Reply #230 on: September 02, 2014, 11:19:31 am »

The first posting in this thread, point 4:
http://www.luminous-landscape.com/forum/index.php?topic=93004.msg757129#msg757129
The prior thread:
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756292#msg756292
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756299#msg756299
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756379#msg756379
http://www.luminous-landscape.com/forum/index.php?topic=92767.msg756381#msg756381
etc.
And there are ArgyllCMS tools too, that compute gamut volume, as well as intersecting volumes.

(And I'd hardly call this forum "color geek heaven" - it's not that much fun.)
If delta E is a linear measure, then naturally you measure gamut volume in delta E cubed.

None of those posts have numbers and units. As in e.g., "56 furlongs". All they talk about is the concept.

And no, delta E cubed would NOT be a gamut measure, unless you believe that luminance is a component of gamut. (Is RGB 10,10,10 a different color to RGB 20,20,20?)

As per my post, a gamut measure would be an area measure, so a square, not a cube. Practically, if you really wanted one, an xy area from a xy gamut plot would be more useful. Although useful for what I'm not sure.

All of which I think makes the point - if a correct measure doesn't immediately come to the mind of the author of ArgyllCMS, then a generally accepted measure doesn't exist outside of deep geek world.

Sandy
« Last Edit: September 02, 2014, 11:21:11 am by sandymc »
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smthopr

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Re: Color management myths and misinformation video
« Reply #231 on: September 02, 2014, 11:26:58 am »


So yes, I think when people dismiss wide gamut working spaces to suggest 'there's no ProPhoto RGB displays' they are making a mountain out of a molehill. Just keep a steady hand on Vibrance and Saturation controls and don't keep moving them if you don't see any update on-screen. Danger Will Robinson, Danger.

Yes, exactly. This idea works in the opposite direction as well.  Why worry about using ProPhoto, when, as you've just pointed out, it's just a molehill.  At least the difference, as in your illustration, is a maximum of 5 DeltaE.

And, all one's editing decisions will be made while looking at sRGB(in this example).  My point is that the large working space doesn't effect one's editing decisions, and as you point out, is not easy to see in your example. We are in agreement, it is a molehill.  So how do you now explain this stuff to the novice?  Isn't that what this thread was about?  Because they will want to know why they need to work in a colorspace that they can't see.

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Bart_van_der_Wolf

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Re: Color management myths and misinformation video
« Reply #232 on: September 02, 2014, 11:45:52 am »

And no, delta E cubed would NOT be a gamut measure, unless you believe that luminance is a component of gamut. (Is RGB 10,10,10 a different color to RGB 20,20,20?)

Sandy, Yes, it is a brighter shade of gray in a three-dimensional space. Its chromaticity is on the axis between whitepoint and blackpoint of the particular space you are using.

Quote
As per my post, a gamut measure would be an area measure, so a square, not a cube. Practically, if you really wanted one, an xy area from a xy gamut plot would be more useful.

Not really, unless you are confusing the CIE1931 diagram for a full description of a gamut, which it isn't. Gamuts are 3-dimensional, and one attempts to describe the perceptually relevant color differences with a delta-E cubed metric. As described in this thread, those delta-E's can be calculated in various ways, some methods are more useful (closer to actual human perception) than others, but none are perfect.

Cheers,
Bart
« Last Edit: September 02, 2014, 12:07:33 pm by BartvanderWolf »
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MarkM

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Re: Color management myths and misinformation video
« Reply #233 on: September 02, 2014, 11:51:55 am »

Sandy, Yes, it is a brighter shade of gray in a three-dimensional space. It's chromaticity is on the axis between whitepoint and blackpoint of the particular space you are using.

Not really, unless you are confusing the CIE1931 diagram for a full description of a gamut, which it isn't. Gamuts are 3-dimensional…

Here is an effective demonstration of this point:
http://brucelindbloom.com/index.html?ChromaticityGamuts.html
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sandymc

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Re: Color management myths and misinformation video
« Reply #234 on: September 02, 2014, 12:00:04 pm »

Sandy, Yes, it is a brighter shade of gray in a three-dimensional space. It's chromaticity is on the axis between whitepoint and blackpoint of the particular space you are using.

Not really, unless you are confusing the CIE1931 diagram for a full description of a gamut, which it isn't. Gamuts are 3-dimensional, and one attempts to describe the perceptually relevant color differences with a delta-E cubed metric. As described in this thread, those delta-E's can be calculated in various ways, some methods are more useful (closer to actual human perception) than others, but none are perfect.

Cheers,
Bart

Bart, yes, in theory, but for the kind of color spaces we're talking about here (sRGB, Adobe RGB, ProPhoto) gamut is defined by red, green and blue tristimulus values in the icc profile. In an LAB space, you can get stuff to go in and out of gamut by changing L, but that's not the way that any non-geek views luminance. So while of course gamuts are 3-d, it's not an explanation that I think would be helpful to non-geeks.

My bad for using "luminance" in the wrong setting.  :-[

Sandy
« Last Edit: September 02, 2014, 12:18:59 pm by sandymc »
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digitaldog

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Re: Color management myths and misinformation video
« Reply #235 on: September 02, 2014, 12:07:01 pm »

Yes, exactly. This idea works in the opposite direction as well.
No it really doesn't, not unless you want to use a simplistic (Garry like) cause and effect principle to suggest it does. Did you see the example of Bill's flower's in the closed post? Or my example of data clumping in dark saturated shadows in the same thread? We could plot the dE differences between what can and cannot be seen on a display but there's far more to the inferior output seen in those examples than a dE difference distance between visible and OOG colors and the effect on the conversions to print.
Quote
At least the difference, as in your illustration, is a maximum of 5 DeltaE.
Actually 6 but now go and convert ProPhoto to the output color space then sRGB to the output color space and the differences in how saturated colors are affected can be an issue as seen in Bill's examples. Suggesting or equating a small dE difference between what we can see between two color spaces on a display and the effect of the differing gamuts on conversions to print is something Gary might propose. Further, your capture device provided you this data. You are perhaps proposing we clip it solely so we can see some colors, while removing colors we can use for output. If you want to do that, go ahead. But retaining and using all the data is for many of us, far more critical than deleting color so we don't have to deal with colors we can't see on one device.
Quote
And, all one's editing decisions will be made while looking at sRGB(in this example).
That statement would only be valid if the only output for the data was your display. There are colors we can retain and print we can't see on the display but could see on the print. Or another person's display. Clipping them so you can see them on one device seems rather pointless unless you're sure the only reproduction will be on that one device.
Do you have a DSLR? If so, when you capture the full resolution image, do you resample down for the web or display and throw away the full resolution data? Even if you're sure the only output will be to the web? After you convert from raw to a TIFF or JPEG (assuming you shoot raw), when you are finished, do you delete the raw file?
Quote
So how do you now explain this stuff to the novice?  Isn't that what this thread was about?
You show them the gamut maps compared to images as I did in my video. You tell them what I told you: do you want to clip colors you can't see on one device to edit them, colors that you can use on another device? Or do you retain all the color data and carefully edit the image, soft proof and use that data? It is then up to them to decide what route to take.

Color data is often about color detail. The dE example I provide for you can't show you this, you have to do a test like Bill did and actually convert the data and print it. Assuming your goal is to print your data.
Assuming that the dE differences on a display between OOG colors of two color spaces equate to what comes off a print is like Gary assuming that Adobe RGB produce dull colors. The gamut of a print and display, the contrast ratio, ability to see subtle color details are different. And that's why a soft proof will never be a 100%, nor is anyone saying it can be. The gamut of the print space doesn't fit your display gamut either. But it is a better predicator of what your print should look like than not using it. A Polaroid never looked like a transparency but many of us shot Polaroids for testing a number of parameters before shooting film, and learned to judge the differences making the Polaroid, like the soft proof, useful.
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digitaldog

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Re: Color management myths and misinformation video
« Reply #236 on: September 02, 2014, 01:44:13 pm »

Here's some radical differences smthopr. We start with a Granger Rainbow that is converted to ProPhoto RGB and then sRGB from Lab, where it was created. The ProPhoto RGB and sRGB iterations are converted to an output color space (Epson 3880 Luster). Big dE differences (keep in mind, they are both in the same output color space seen here):
http://www.digitaldog.net/files/Granger_sRGB_ARGB_Epson_CT.jpg
sRGB to Epson on the left side of this report.

Now let's look at a close up of one area of the two images in Photoshop, 100% zoom. What I see on this end, which may not appear on the web, is of course a more saturated color from ProPhoto to the output color space (Left side in this example) but as importantly, look at the effect of smoothness using ProPhoto or lack thereof from sRGB when converted to the output color space on the right side.
http://www.digitaldog.net/files/Granger_sRGB_ARGB_Epson.jpg

Clearly the source working space used to convert to the output color space plays a role in both the appearance of saturation (albeit on a display for this print) but also in terms of how smoothly colors map to the output color space (Epson 3880 luster). And this is a JPEG so you'll see some artifacts in both. None the less, like Bill's flowers, I think this illustrates how the two RGB working spaces and their gamuts affect conversions to the output color space. Starting with a larger gamut has advantages IMHO in both the appearance of saturation and smoothness. It might not be a worthwhile advantage to some, and that's a value judgement.
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LPowell

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Re: Color management myths and misinformation video
« Reply #237 on: September 02, 2014, 04:34:41 pm »

If I lower the saturation by 1/2 I can fit my wide gamut image into sRGB for example. Then, I can increase my saturation and get back an image the retains the color detail, at the appropriate values for sRGB.  Nothing lost. Still "late binding". We do this all the time in motion capture.
Yes, you can dial down the saturation when recording video in Rec 709 (~sRGB) color space, but there is something lost. The main deficiency in the gamut of sRGB compared to aRGB or ProPhoto is in saturation range, so if you reduce saturation level at capture, you can indeed fit a wider range of saturation into the recording. What you lose however, is the effective bit-depth of your recording's saturation range. When you reduce saturation by 50% at capture and increase it by 200% in post, you lose one bit of color resolution in the process. And since Rec 709 is typically recorded at 8-bit resolution, degrading color bit-depth to 7-bits can be quite noticeable while grading in post. The reason you did this, however, is because you'd rather lose some details in color resolution in order to prevent the intensely saturated colors from being clipped.

In practice, you can make a judgment call: when you're shooting a muted, low-saturation scene, leave it be. When shooting a vividly-colored scene, you may want to turn down the saturation a bit, and boost it later in post. But at the time you boost the saturation, your color working space does need to have a broader gamut than Rec 709 or sRGB, in order to prevent saturation clipping.
« Last Edit: September 02, 2014, 04:48:12 pm by LPowell »
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digitaldog

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Re: Color management myths and misinformation video
« Reply #238 on: September 02, 2014, 04:44:12 pm »

I just put together a "Gamut Test File" TIFF for anyone who wants to test output using ProPhoto versus anything smaller. All the images are mine except I did include Bill Atkinsion's awesome 14-ball test image (with credit to Bill). All the images expect Bill's were rendered in Lightroom from raw to ProPhoto 16-bit. Bill's originals were built in Lab 16-bit. Print using this 16-bit file to your output device, then convert to say sRGB and maybe Adobe RGB and make another print. On my 3880, it is pretty significant visually IMHO.

http://www.digitaldog.net/files/Gamut_Test_File_Flat.tif
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smthopr

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Re: Color management myths and misinformation video
« Reply #239 on: September 02, 2014, 05:26:45 pm »

Here's some radical differences smthopr. We start with a Granger Rainbow that is converted to ProPhoto RGB and then sRGB from Lab, where it was created. The ProPhoto RGB and sRGB iterations are converted to an output color space (Epson 3880 Luster). Big dE differences (keep in mind, they are both in the same output color space seen here):
http://www.digitaldog.net/files/Granger_sRGB_ARGB_Epson_CT.jpg
sRGB to Epson on the left side of this report.

Now let's look at a close up of one area of the two images in Photoshop, 100% zoom. What I see on this end, which may not appear on the web, is of course a more saturated color from ProPhoto to the output color space (Left side in this example) but as importantly, look at the effect of smoothness using ProPhoto or lack thereof from sRGB when converted to the output color space on the right side.
http://www.digitaldog.net/files/Granger_sRGB_ARGB_Epson.jpg

Clearly the source working space used to convert to the output color space plays a role in both the appearance of saturation (albeit on a display for this print) but also in terms of how smoothly colors map to the output color space (Epson 3880 luster). And this is a JPEG so you'll see some artifacts in both. None the less, like Bill's flowers, I think this illustrates how the two RGB working spaces and their gamuts affect conversions to the output color space. Starting with a larger gamut has advantages IMHO in both the appearance of saturation and smoothness. It might not be a worthwhile advantage to some, and that's a value judgement.

Pretty cool Andrew.  That illustrates the effect nicely.

I guess my thought was though, if one is editing the image on a display, will one visually bring into gamut most of the out of gamut colors when adjusting the image? I'm thinking about RAW conversion.  Would I just see the blocked up out of gamut colors and reduce saturation based upon my view on a display? And thereby preserving colors that way?

But I do get the whole idea.  Why think of these things when I can just keep everything in ProPhoto and never worry about clipping.  I'll likely clip some in editing (or my image might look a little dull), but they're always there if I want em'.  Extra color detail may show up in a print, that I can't see on my monitor or even softproof.  Probably I will prefer that, or I'll re-edit, and make a new print.

The tough part is explaining all this easily to beginners.  I might have missed some posts. Have you made a video yet Andrew?
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Bruce Alan Greene
www.brucealangreene.com
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