Out of gamut badness and a quick fix
rutt
Registered Users Posts: 6,511 Major grins
Here's a bad thing that happens to me once in a while. I do some edit and get something that looks pretty good in PS. Then I save it out, upload to SM and it looks terrible, not at all the same as in PS. What's going on?
Often the problem is that the image is out of gamut. That means that it has some colors that can't be reproduced perfectly within it's color profile. It's very easy to make such colors with ACR and especially LAB curves.
Here is an example. Today I editted a shot of Ginger's tombstone and flowers. Looked pretty nice to me when I got done, but once I uploaded, it looked terrible. Here it is:
Here's what I saw in PS:
I turned on View->Gamut Warning, and sure enough almost all the shot was grayed out, meaning out of gamut.
The quick fix for this problem is to move the image in and out of the CMYK color space. Once it's been through CMYK and back to RGB, it will all be within gamut and will look the same on the web as in PS. That's how I got the second shot online.
Why? The translation into CMYK is not fully determined. How much black ink to use as opposed to mixing CMY to make black is a decision PS makes. So it has a "lossy" algorithm that does the translation. And while it's at it, it obeys the color profile and gets eveything within gamut. Sometimes this means that you will loose a little sometihing, usually the deepest blacks. You can restore these in CMYK by steepening the dark end of the K curve a bit. But this is a small price for having your image actually look the way it's supposed to.
Often the problem is that the image is out of gamut. That means that it has some colors that can't be reproduced perfectly within it's color profile. It's very easy to make such colors with ACR and especially LAB curves.
Here is an example. Today I editted a shot of Ginger's tombstone and flowers. Looked pretty nice to me when I got done, but once I uploaded, it looked terrible. Here it is:
Here's what I saw in PS:
I turned on View->Gamut Warning, and sure enough almost all the shot was grayed out, meaning out of gamut.
The quick fix for this problem is to move the image in and out of the CMYK color space. Once it's been through CMYK and back to RGB, it will all be within gamut and will look the same on the web as in PS. That's how I got the second shot online.
Why? The translation into CMYK is not fully determined. How much black ink to use as opposed to mixing CMY to make black is a decision PS makes. So it has a "lossy" algorithm that does the translation. And while it's at it, it obeys the color profile and gets eveything within gamut. Sometimes this means that you will loose a little sometihing, usually the deepest blacks. You can restore these in CMYK by steepening the dark end of the K curve a bit. But this is a small price for having your image actually look the way it's supposed to.
If not now, when?
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Comments
I went up to PS, dug out my shot, went to view, then gamut warning (which I had never heard of before), all this grey stuff showed up. So I clicked again, the grey stuff went away.
I put it in CMYK, and while I was there took out the black dust spot. Then put it back in RGB. No more grey, made a jpg. Will bring it down later.
Very useful info.
Do you find things "out of gamut" often?
ginger
As I said, it's easy to do with LAB curves.
Cheers
--don
Try the trip through CMYK on your way to sRGB next time. Usually it works OK, but if not you can correct in CMYK where it's pretty hard to make a mess because more ink makes things darker and the real problem is the mythical "ink police", something that really doesn't matter for online viewing.
-don
You have to be willing to readjust in CMYK after the move. Your beautiful saturated colors get "gray" in CMYK by being polluted by too much ink. To get bright reds, you have to make sure you don't have much (or any) cyan. For bright blues, decrease magenta. In other words, you want shallow curves in the highlights of the the opponent colors to the ones you want to emphasize.
I have had some prints that looked very nice and smooth on the monitor, and yet when printed, had very blotchy, posterized areas of dense color.
When I checked, these areas were indeed out of gamut. Like you said John, with a trip to CMYK and back, the colors no longer were out of gamut, and the print looked much better the second time around.
Out of gamut is a subject I would like to discuss in more detail.
Moderator of the Technique Forum and Finishing School on Dgrin
I mentioned earlier that if I make my color adjustments in CMYK it sure looks like I lose more color and contrast. In otherwords my images will look less saturated and flatter and have less pop If I adjust out of gamut color in CMYK before or instead of adjusting them using the ezprints profile.
I can only assume (possibly incorrectly) that the ezprints colorspace has a wider gamut than the CMYK colorspace, at least through the range of colors I am capturing and trying to print. If someone could post an overlay of both profiles, we could at least see the differences in the two colorspaces.
I just don't see why you would be proofing for printers that smugmug/ezprints are not using when ezprints/smugmug already give us a profile to use that appears to be a wider colorspace than CMYK.
-don
Unfortunately, we have very different points of view on this and it's a critically important topic.
First, going to CMYK and back can only lose colors, not create them. Here is the CMYK gamut compared to some RGB ones:
(This chart is from http://www.peimag.com/pdf/pei01/pei0501/eveningpei0501.pdf )
In the small areas where CMYK is broader than sRGB or Adobe RGB, you're not going to create colors because they don't exist in your original. But look at what you lose...
Second, when you say your out of gamut warning shows gray, how is your proof color default set up? If it's set for CMYK, then it will show large areas of gray because as you see in the chart above, much of what's in gamut for sRGB is out of gamut for CMYK.
Third, when you say it moves all colors into gamut when you convert to CMYK, it moves them into gamut for CYMK. Why would we care about that? We care about what's in gamut for sRGB, which is what the web uses.
Fourth, conversion from a broader color space to a narrower one is very difficult because you are asking a computer to make decisions about color substitution (some crayon is available in sRGB that isn't in CMYK, so which different crayon that is in CMYK should we choose to draw it?).
Fifth, you're going to be disappointed in saturations in CMYK. That's why Rutt has to go through machinations after.
Margulis makes it short and sweet:
[font=verdana,arial,helvetica,sans serif]"CMYK is related to and in some ways very similar to RGB - although when it comes to saturation intensity or hue and saturation variation it is often disappointing when compared to the RGB original. Converting RGB to CMYK with any degree of accuracy is no small task and impossible for out of gamut hues."
Out of gamut hues are the areas in the chart above that your RGB color space has that CMYK does not.
Sixth, I'm really sorry if I'm daft, but can you help me understand this is what I saw in Photoshop? If you saw it in Photoshop and were working in sRGB, then that's what you'll see on smugmug. There's no concept of out of gamut because it's all in gamut — it's all sRGB.
As an example, this is all in gamut:
If you were to set your proof colors for CMYK and do a gamut check, then a lot of the image would be gray. But why is that relevant? When I upload it to smugmug, it looks exactly as you see it there. When I print it through EZ Prints, it also looks exactly the same. If I convert it to cmyk and back, I lose the most vibrant colors (which are out of gamut for CMYK).
Sorry for the quick & dirty — I'm under the gun, but tell me where I'm wrong.
Thanks,
Baldy
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If you are using smugmug's automated printing services under normal circumstances you would never want to convert to CMYK or proof with CMYK when uploading a print to smugmug with the current printers that are being used. You are simply clipping or clamping or chopping colors that you don't need to be getting rid of and in many cases could have been preserved.
You should use the ezprints profile to proof with and then convert to srgb for upload to smugmug if you want the image to display and print correctly. If you go through CMYK you will simply lose too many color(s) under too many circumstances.
It would be interesting to see the ezprints print gamut overlay against srgb, I say. I know it is close, but it is not exactly the same. I'm an adobeRGB fan as well Baldy, but we won't go there today or in this thread. :tiptoe
Cheers
-don
What's going on?
I don't mean to be smart, but when you use this procedure you won't have to worry about what colors you are losing and why when you convert to CMYK because you should not be doing that procedure anyway. Once you have the ezprints profile installed you can see the gamut differences because you will see different warnings on the same image when proofing in CMYK and ezprints and this will help you understand the whole procedure better.
Cheers and good luck.
-don
I found something out. The first version, which has not been dragged through CMYK looks right in PS because I have View->Proof Setup set to "Working CMYK". When I set this to "Windows RGB" it looks pretty bad. When I set it to "Macintosh RGB" or "Monitor RGB" it looks worse, the same way as I see it in the browser. The second image, which has made the trip throuh CMYK also looks different depending on this setting, but much less so.
So what's going on? Which Proof Setup is the right one to use? Does the EZPrints profile add a new proof setup? Is this just the tip of some huge iceberg?
The problem is, when you use save for web in Photoshop, why do you see a color shift? Another way to look at it is when you open a file from disk in your browser and you open the same file in Photoshop, why do they look different?
On my system and for your image, they don't, but for many people they do.
The answer is Photoshop knows for color spaces and ICC profiles and your browser doesn't*. If you open an Adobe RGB file in Photoshop, it knows how to display it.
So here's an experiment. I don't remember if you're on a Mac or PC, but if PC, go to control panel > display > settings > advanced > color management and choose sRGB Color Space Profile. Now open your file with a browser and with Photoshop. Do they look the same now?
(You can do the same on the Mac, but I believe the Mac calls it TV.)
Here's more:
http://www.gballard.net/psd/saveforwebshift.html
I hope this helps.
Thanks,
Baldy
*Except for certain circumstances on the Mac with Safari or IE.
Without getting technical the CMYK profile is for a different type of printer that you are not worried about right now. The ezprints is for printing on ezprints printers and helps us accurately reproduce an image and allows usto get all of the color out of a print we can. This might help you here: http://www.smugmug.com/help/print-color. You will also find the profile there.
Hope that helps.
-don
We actually have a section on pleasing skin tones where we mention a way to adjust skin tones in CMYK. The reasons we do are, (1) the bulk of print volume we do are from photographers of people — weddings, studio, event, etc. — (2) those shots rarely have out of gamut colors for CMYK, (3) even if they did, no one notices because they're looking at the people, (4) correcting for skin tones is so nice in CMYK (I do it all the time), and (5) returned prints come mainly from shots with skin tones and it's for the skin tones that they get returned. I'm not sure I've ever heard of a print being returned because the color of the bride's bouqet wasn't quite right.
For some reason, dpreview and dgrin are largely populated by people who shoot fine art/landscape, but our pro customers are largely people who shoot people.
For fine art/landscape, I agree with you.
I hope this helps.
Thanks,
Baldy
The point of this thread is out of gamut color, so I guess was not thinking of nuking any flesh tones, especially with the nature examples posted to the beginning of this thread. This is a great subject though, that is for sure. Just don't make a habit of adjusting out of gamut color in CMYK, I don't think that is anywhere near the right way to go for any image that has a substantial color range.
Cheers
-don
I did go to the control panel and I made my default color space sRGB. It was a color space that was compatible with Dell before.
What is that going to do to my photos or any color on my screen?
Also, Don, how do you set up that EZ print "out of gamut" thing? That would be handy. Right now that is not our concern, but I can see that it might be mine sometime. (Never mind, Don, thanks I see you provided a link with that info)
ginger, night all
-don
Thanks, Don. That helps alot.
ginger
-don
Thanks, that was a helpful resource. The issue seems to be that I'm using Mac gamma. Before saving shots for the web, I suppose I need to look at them with Windows RGB Proof Setup.
This still leaves one question unanswered. Why did the trip through CMYK result in an image that looks more alike in all 4 Proof Setup settings? I asked this question on Dan's colortheory list. If I get an interesting reply, I'll repost here. Here is a speculation: the gamut of CMYK is a real lowest common denominator. So images which have been forced into it are less demanding in all color spaces and with all profiles.
Unfortunately, I don't sell any prints through dgrin. (Maybe if I took a weekend and organized my galleries better, I would.) I do a fair amount of my own printing with an Epson 4k and 2200 and I almost always get the color I expect and I suppose I've always been using Working CMYK as my Proof Setup. Perhaps I should get the right profiles for these printers? But it hasn't been broken, so I haven't fixed it.
Although I know a lot about color theory, I am a real color management-o-phobe. I guess I might need to start fixing that. Is there a primer somewhere?
"This still leaves one question unanswered. Why did the trip through CMYK result in an image that looks more alike in all 4 Proof Setup settings? I asked this question on Dan's colortheory list. If I get an interesting reply, I'll repost here. Here is a speculation: the gamut of CMYK is a real lowest common denominator. So images which have been forced into it are less demanding in all color spaces and with all profiles.
In the grand color scheme of things, I suppose you could look at it like that. Depending on the image, you are quite possibly correct that the CMYK appears to be the LCD, the CMYK space just ain't that big, comparison wise.
Rutt said:
"Unfortunately, I don't sell any prints through dgrin. (Maybe if I took a weekend and organized my galleries better, I would.) I do a fair amount of my own printing with an Epson 4k and 2200 and I almost always get the color I expect and I suppose I've always been using Working CMYK as my Proof Setup. Perhaps I should get the right profiles for these printers? But it hasn't been broken, so I haven't fixed it."
If you are getting good results, many folks say don't fix what does not seem to be broke. You might have things messsed up just enough to produce the right results.
Rutt said:
"I suppose I am left with one more question.
Why is this rare? I go along mostly and things work just fine, even though I have horrible Proof Setup == Working CMYK and horrible Mac gamma as my monitor profile. And things mostly work great. Just once in a blue moon, I get these images that desaturate and loose contrast when viewed in the browser. Why doesn't it happen all the time?"
The most common cause for an image to appear flat and desaturated is an adobeRGB image uploaded to the web. This space, not converted to sRGB before upload will much of the time cause that flat desaturated look on a monitor. Otherwise, it's only a guess, but you may be having some trouble with very colorful images just because of that workflow you are using. Some images just don't make it through unscathed. Don't forget to check the earthboundlight link, he talks a little bit about adobeRGB and the 2200 specifically.
Here is a few ok resources on the color and gamut subjects:
Introduction to Color Management:
http://www.boscarol.com/pages/cms_eng/index.html
Out of Gamut Vocabulary:
http://www.creativepro.com/story/feature/11132.html
Color Management:
http://www.computer-darkroom.com/ps8_colour/ps8_1.htm
Photoshop Color:
http://www.nebulus.org/tutorials/2d/photoshop/color/index.html
Hue Saturation and Luminance
http://www.nebulus.org/tutorials/2d/photoshop/color/color2.html
Luminance:
http://www.nebulus.org/tutorials/2d/photoshop/color/color3.html
Color Management:
http://www.normankoren.com/color_management.html#Basics
Good general setup stuff:
http://www.dummies.com/WileyCDA/DummiesArticle/id-2380,subcat-MULTIMEDIA.html
Photoshop Color Settings:
http://www.earthboundlight.com/phototips/photoshop-color-settings.html
Color and Inkjets from Adobe:
http://www.asia.adobe.com/print/tips/phs7inkjet/main.html
PSCS Color Management:
http://www.computer-darkroom.com/ps8_colour/ps8_1.htm
PS6 Out of Gamut: Soft Proofing
http://www.creativepro.com/story/feature/10150.html
PS6 Out of Gamut: Color Management
http://www.creativepro.com/story/feature/14331.html
PS6 Out of Gamut: PS6 Gets Smart with Color
http://www.creativepro.com/story/feature/9155.html
Cheers
-don
Talk about color problems! I can't read your post at all. The color you used is just to light on my mac and for my old eyes. Please, would you mind editing to use darker colors for text. Thanks.
OK, not a problem, I'll change the colors for you. I am going to put those links in a more useful order as well. Sorry you are having trouble reading the post, that was not my intent.
-don
At least I was able to diagnose this color problem. You used white as the text color and I have my dgrin CP setup with a forum skin of "White". White on white is invisible. Maybe I should default, but I like black on white a lot.
Cheers
-don
Rutt said:
"This still leaves one question unanswered. Why did the trip through CMYK result in an image that looks more alike in all 4 Proof Setup settings? I asked this question on Dan's colortheory list. If I get an interesting reply, I'll repost here. Here is a speculation: the gamut of CMYK is a real lowest common denominator. So images which have been forced into it are less demanding in all color spaces and with all profiles."
In the grand color scheme of things, I suppose you could look at it like that. Depending on the image, you are quite possibly correct that the CMYK appears to be the LCD, the CMYK space just ain't that big, comparison wise.
Rutt said:
"Unfortunately, I don't sell any prints through dgrin. (Maybe if I took a weekend and organized my galleries better, I would.) I do a fair amount of my own printing with an Epson 4k and 2200 and I almost always get the color I expect and I suppose I've always been using Working CMYK as my Proof Setup. Perhaps I should get the right profiles for these printers? But it hasn't been broken, so I haven't fixed it."
If you are getting good results, many folks say don't fix what does not seem to be broke. You might have things messsed up just enough to produce the right results.
Rutt said:
"I suppose I am left with one more question.
Why is this rare? I go along mostly and things work just fine, even though I have horrible Proof Setup == Working CMYK and horrible Mac gamma as my monitor profile. And things mostly work great. Just once in a blue moon, I get these images that desaturate and loose contrast when viewed in the browser. Why doesn't it happen all the time?"
The most common cause for an image to appear flat and desaturated is an adobeRGB image uploaded to the web. This space, not converted to sRGB before upload will much of the time cause that flat desaturated look on a monitor. Otherwise, it's only a guess, but you may be having some trouble with very colorful images just because of that workflow you are using. Some images just don't make it through unscathed. Don't forget to check the earthboundlight link, he talks a little bit about adobeRGB and the 2200 specifically.
Here are a few ok resources on the color and gamut subjects, some are more useful than others:
Introduction to Color Management:
http://www.boscarol.com/pages/cms_eng/index.html
Out of Gamut Vocabulary:
http://www.creativepro.com/story/feature/11132.html
Color Management:
http://www.computer-darkroom.com/ps8_colour/ps8_1.htm
Photoshop Color:
http://www.nebulus.org/tutorials/2d/photoshop/color/index.html
Hue Saturation and Luminance
http://www.nebulus.org/tutorials/2d/photoshop/color/color2.html
Luminance:
http://www.nebulus.org/tutorials/2d/photoshop/color/color3.html
Color Management:
http://www.normankoren.com/color_management.html#Basics
Good general setup stuff:
http://www.dummies.com/WileyCDA/DummiesArticle/id-2380,subcat-MULTIMEDIA.html
Photoshop Color Settings:
http://www.earthboundlight.com/phototips/photoshop-color-settings.html
Color and Inkjets from Adobe:
http://www.asia.adobe.com/print/tips/phs7inkjet/main.html
PSCS Color Management:
http://www.computer-darkroom.com/ps8_colour/ps8_1.htm
PS6 Out of Gamut: Soft Proofing
http://www.creativepro.com/story/feature/10150.html
PS6 Out of Gamut: Color Management
http://www.creativepro.com/story/feature/14331.html
PS6 Out of Gamut: PS6 Gets Smart with Color
http://www.creativepro.com/story/feature/9155.html
Ok, there it is in ugly, but full living color, no whites.
Hope this helps.
-don
I'm really really sure I don't have the problem of the image being in adobeRGB.