Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: mdijb on September 05, 2009, 03:46:02 pm
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When you hit SHift-command-Y, out of gamut colors get a gray mask over them. The profile selected in softproofing determines which colors are out of gamut and which ones will have the gray mask appear over them. I want to be able to select these specific colors . IF you try using the Out of gamut colors option with the color range selection method, the colors selected do not match those found with the first method, and are not accurate.
How can I select accurately these out of gamut colors?
MDIJB
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This might work: add a hue/sat adjustment layer to the image with it under softproof. Select each of the RGB colour channels, widen or narrow the sliders defining the affected gamut according to which hues you think are most likely OOG, and de-saturate. As you desaturate see whether this affects the amount of gray overlay in the relevant areas. I haven't tested this, so it's a logical inference.
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If I’m not mistaken, the selection via Color Range > Out-Of-Gamut always refers to the CMYK working space as defined in the Color Settings. Accordingly, the colors selected do match those found with Proof Setup > Working CMYK. In other words, any custom proof setup is ignored for the selection.
Just as for the background of the mismatch.
Peter
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This might work: add a hue/sat adjustment layer to the image with it under softproof. Select each of the RGB colour channels, widen or narrow the sliders defining the affected gamut according to which hues you think are most likely OOG, and de-saturate. As you desaturate see whether this affects the amount of gray overlay in the relevant areas. I haven't tested this, so it's a logical inference.
I tried your suggestion and it seems to work--the gray overlay reduces as the slider moves. The only negative is that all the similar colors in the entire image are affected, even with moving the color sliders very close together. I think adding a layer mask will help limit this.
Thanks for the help
MDIJB
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When you hit SHift-command-Y, out of gamut colors get a gray mask over them. The profile selected in softproofing determines which colors are out of gamut and which ones will have the gray mask appear over them. I want to be able to select these specific colors . IF you try using the Out of gamut colors option with the color range selection method, the colors selected do not match those found with the first method, and are not accurate.
How can I select accurately these out of gamut colors?
MDIJB
I don't know why you'd want to do this, but you can select "Out of Gamut" colors (which is a crude, hard-edged "tool") using the Color Range command as you've seen, then play with the Refine Edge command. And as Peter has point out, its based on the CMYK color space setup in your Color Settings (not real useful).
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I tried your suggestion and it seems to work--the gray overlay reduces as the slider moves. The only negative is that all the similar colors in the entire image are affected, even with moving the color sliders very close together. I think adding a layer mask will help limit this.
Thanks for the help
MDIJB
Glad it helped - and yes you can paint Black on the layer mask to hide areas of unwanted desaturation.
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I don't know why you'd want to do this, but you can select "Out of Gamut" colors (which is a crude, hard-edged "tool") using the Color Range command as you've seen, then play with the Refine Edge command. And as Peter has point out, its based on the CMYK color space setup in your Color Settings (not real useful).
In the process of creating my Photopaintings, some colors become over saturated and loose detail when printing. I want to reduce the saturation to retain the detail and need to select only the out of gamut colors.
See my website www.mdiimaging.com
MDIJB
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Or, a "saturation mask" may do the trick.
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In the process of creating my Photopaintings, some colors become over saturated and loose detail when printing. I want to reduce the saturation to retain the detail and need to select only the out of gamut colors.
See my website www.mdiimaging.com
MDIJB
Very interesting and stimulating work Michael, and I can see your problem quite clearly - part of your style features very intense colours which do need careful attention in a digital workflow.
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Or, a "saturation mask" may do the trick.
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Would you care to elaborate specifically what you have in mind - there are a number of approaches.
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Would you care to elaborate specifically what you have in mind - there are a number of approaches.
Yes, Google easily points us to a variety of techniques.
One particular approach which I liked for its simplicity is to convert Saturation to Grayscale by means of Selective Color (http://tech-slop.serveit.org/wiki/index.php?title=Extract_saturation_to_greyscale). Then, it just requires to make it a layer mask for the Hue/Sat.-tool and a respective adjustment layer (preferably in Saturation blend mode). Some further tonal tweaking of the mask and Done. Actually I used this approach a lot to increase global saturation (with an inverted mask of course), before Vibrance arrived in CR as well as in Photoshop. Can’t say if it is the best method to edit and reduce saturation towards an output (e.g. printer) gamut.
Assuming that many of us now have colorful images in ProPhoto RGB which need to be prepared for inkjet print output, there seems to be surprisingly little interest in this subject. Doesn’t it.
Peter
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With today's tools you don't need all those convoluted procedures to bring saturated colour into gamut. I believe in the KIS principle.
Mark
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With today's tools you don't need all those convoluted procedures to bring saturated colour into gamut. I believe in the KIS principle.
Exactly! Just use good output profiles, soft proof, do minor editing if necessary for that output and move on.
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With today's tools you don't need all those convoluted procedures to bring saturated colour into gamut. I believe in the KIS principle.
Mark
OK - would you care to elaborate what you have in mind,
how to Keep It Simple ?
Peter
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OK - would you care to elaborate what you have in mind,
how to Keep It Simple ?
Let the profile do the gamut mapping.
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OK - would you care to elaborate what you have in mind,
how to Keep It Simple ?
Peter
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What Andrew just said. And use an HSL or SelCol Adj Layer to make the necessary de-saturating moves under softproof with your printer profile active and Simulate Paper White checked. Even better, in Lightroom/ACR you can use negative Vibrance (in PSCS4 too for this one), or de-saturate individual colour groups in the HSL Panel.
Mark
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What Andrew just said. And use an HSL or SelCol Adj Layer to make the necessary de-saturating moves under softproof with your printer profile active and Simulate Paper White checked. Even better, in Lightroom/ACR you can use negative Vibrance (in PSCS4 too for this one), or de-saturate individual colour groups in the HSL Panel.
Keep It Simple is often related to some kind of a 80-20 rule:
80% performance with 20% effort. Nice and appreciated whenever it works.
Before relying on the rigid mechanics even of a "good output profile" and/or practicing any global de-saturation, I’d always to try (try !) to convert to a smaller matrix space first, before targeting the final printer profile. Then, judge by the final print.
Theory here is anything but straight, but sometimes it can be a 80-20 thing as well.
Peter
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Let the profile do the gamut mapping.
I agree.
Jacopo
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If for some reason of artistic bent, having nothing to do with printing the image (since you have the best practice for that from Mark and Andrew) and you really, really, really do want to create a selection based on the displayed gamut warning here's an option to get at least close....
Make the image as large as possible, still fitting on the monitor. Turn on gamut warning. Do a screen grab and copy into a new image, crop to extract the image and resize to the original. Copy the image with the gamut warning back to the original image and set blending mode to difference - any pixels with no change, ie not part of the warning will be black and can be selected to create the mask. Fuss with the refine edges to deal as much as possible with the artifacts created by the extreme uprezzing, and that will get you close. Crude, but it looks like it might be a bit closer than Select Range OOG.
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Still I would believe that described procedure for a Color Managed Raw Workflow (http://www.adobe.com/digitalimag/pdfs/phscs2ip_colormgraw.pdf) is a "best practice" and defines the starting point. With the given example, global saturation even needs to be increased to preserve the overall appearance (p. 10-11). Hence, with an image which also includes a bunch of oog colors, treatment needs to be selective – unless of course the Lut of the printer profile would always "automatically" provide a best possible mapping…
Peter
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MDIJB
The following technique is what I call KIS and still gives you control of the color output. See tip 7. Works for me:
http://www.naturescapes.net/docs/index.php...better-prints#7 (http://www.naturescapes.net/docs/index.php/index.php/category-image-editing/37-image-editing/168-ten-tips-for-better-prints#7)
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The following technique is what I call KIS and still gives you control of the color output. See tip 7. Works for me:
http://www.naturescapes.net/docs/index.php...better-prints#7 (http://www.naturescapes.net/docs/index.php/index.php/category-image-editing/37-image-editing/168-ten-tips-for-better-prints#7)
Excellent article!
Three smileys:
Peter
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If for some reason of artistic bent, having nothing to do with printing the image (since you have the best practice for that from Mark and Andrew) and you really, really, really do want to create a selection based on the displayed gamut warning here's an option to get at least close....
Make the image as large as possible, still fitting on the monitor. Turn on gamut warning. Do a screen grab and copy into a new image, crop to extract the image and resize to the original. Copy the image with the gamut warning back to the original image and set blending mode to difference - any pixels with no change, ie not part of the warning will be black and can be selected to create the mask. Fuss with the refine edges to deal as much as possible with the artifacts created by the extreme uprezzing, and that will get you close. Crude, but it looks like it might be a bit closer than Select Range OOG.
I treid you approach and the problem is that the accessory called GRAB that came with my Mac appears to not be color managed. The colors change alot with the screen grab, and when placed back into Photoshop, they are not the original. This means that there is alot that shows up when Difference mode is used. The OOG colors are there and appear accurate, but there is a lot of other stuff that lights up as well. Good idea though.
MDIJB
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When you hit SHift-command-Y, out of gamut colors get a gray mask over them. The profile selected in softproofing determines which colors are out of gamut and which ones will have the gray mask appear over them. I want to be able to select these specific colors . IF you try using the Out of gamut colors option with the color range selection method, the colors selected do not match those found with the first method, and are not accurate.
How can I select accurately these out of gamut colors?
MDIJB
For what it's worth, the gamut warning in Photoshop is notoriously inaccurate.
Peter
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For what it's worth, the gamut warning in Photoshop is notoriously inaccurate.
Peter
Well, I don't know what it's worth because I don't know what this statement is based on. Is there a body of research you can point to which establishes this case unambiguousy? One known problem with gamut warning, in case this is what you mean, is its binary nature. It's either ON or OFF, no matter how little or how much the colours concerned may be OOG.
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I treid you approach and the problem is that the accessory called GRAB that came with my Mac appears to not be color managed. The colors change alot with the screen grab, and when placed back into Photoshop, they are not the original. This means that there is alot that shows up when Difference mode is used. The OOG colors are there and appear accurate, but there is a lot of other stuff that lights up as well. Good idea though.
MDIJB
You could eliminate that issue by grabbing twice, once with the gamut warning on and once off and use those two images to create the difference mask.
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You could eliminate that issue by grabbing twice, once with the gamut warning on and once off and use those two images to create the difference mask.
Thanks, I'll try that nex.
Where do all your ideas come from?? You are good!!