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Keeping reds when going from RGB to CMYK
Sean Sperry, Student/Intern, Photographer
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Missoula | MT | USA | Posted: 4:39 PM on 07.13.03 |
->> I’m looking for a few Photoshop tricks if there are any on keeping a decent color pallet. Photos that contain nice reds in RGB mode are washing out when transferring to CMYK and tend to print flat with a pinkish cast.
Apart from all of the technical aspects and variables involved with screen calibration and press runs I’m simply looking for methods one can use in photoshop to stay in the red.
Thanks
Sean |
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Michael Hickey, Photographer
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Muncie | IN | USA | Posted: 9:58 PM on 07.13.03 |
->> If the red you are wanting is out of the CMYK gamut you are out of luck because it can't happen. You might try soft proofing while you are in the RGB mode and that will tell you what your reds will do after conversion and then you can adjust accordingly, getting them as close to your liking as possible.
By the way, what are your Photoshop settings? What working spaces are you working in and do you have CMYK setups that correlate to your press as well? |
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Ron Scheffler, Photographer
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Toronto area (Hamilton) | Ontario | Canada | Posted: 10:47 PM on 07.13.03 |
->> This is my quick and dirty fix when making conversions from RGB to CMYK when prepping files for print at the local newspaper:
After making the conversion to CMYK in Photoshop, go to Selective Color (Image>Adjustments>Selective Color). Red is the default color that appears. Slide the Magenta slider to the right until you think you have close to the right red. It might also help to slide the yellow over to the right somewhat as well to keep the red from shifting too far to the magenta side.
This should help you with anemic red reproduction but it's not guaranteed to work perfectly. However, for newspaper reproduction, it's a quick fix and will punch up the reds nicely.
What this won't fix is a loss of detail in reds. If there are subtle variations of details and tones in reds, and after converting to CMYK you find it all turns into a uniform blob of color, then you are dealing with gamut problems and the suggestion Michael makes would be helpful. If reds, or any color, are out of gamut, you should get a warning in the info window. A quick fix might be to select all of the red areas with the Color Range tool and desaturate that selection. Or, select the reds before making major tonal adjustments with curves or levels, invert the selection and make the adjustment so that it excludes the reds. This could be tricky though along the transition area of the selection, resulting in poor results if not done carefully.
In order to soft proof, you should have the CMYK color space you plan to convert to set up as your default CMYK space, then you can simply command/apple Y for the CMYK representation without actually making the conversion. Just command/apple Y again to switch back to RGB representation. |
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Sean Sperry, Student/Intern, Photographer
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Missoula | MT | USA | Posted: 9:00 PM on 07.14.03 |
->> Michael,
Were currently running photoshop 6.0, the Chronicle's presses are relatively new and the photostations were just recalibrated within the last month. I think your right on with saying the photos were out of the CMYK gamut, as I looked through a few problem photos and they tended to be out of range.
Ron,
Thanks for the selective colors suggestion I typically use it on the neutral setting but forgot about selecting individual colors this appears to have helped a bit in punching up reds in the photos.
Thanks
Sean |
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Michael McLoone, Photographer
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Cary | NC | USA | Posted: 9:27 PM on 07.14.03 |
->> Ron,
With your tip on adjusting reds in the CMYK mode will it cause your flesh tones to be overly red? And what if a person were to do some hue saturation in the red areas before or after coverting to CMYK? Just curious.
Michael |
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Ron Scheffler, Photographer
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Toronto area (Hamilton) | Ontario | Canada | Posted: 5:48 PM on 07.15.03 |
->> Michael,
Yes, adjusting the reds can also affect skin tones. To be safe, it's best to do a Color Range selection of the red areas you want to rescue/adjust. This will generally prevent any changes to other less red areas such as skin tone that may already look just the way you want it to be.
Generally you should keep an eye on colors that can easily go out of gamut, such as reds, when working in RGB mode. I don't see any problem with making hue/saturation adjustments in RGB (which I do all the time), just watch that the changes are within range (if the intention is to later convert to CMYK). This also goes for Levels and Curves adjustments. An s-curve will generally boost contrast and can push colors out of gamut.
If I'm working on images that will be converted to CMYK I'll leave saturation adjustments until after the conversion. Also, sometimes adding saturation doesn't make the colors much richer. You can go back to Selective Color and play around with each color - for example if a sky isn't blue enough, boost the amount of cyan in the cyan and blue color options. Using the sky example again, I might do a Color Range selection of the sky and play with the red channel in Curves adding a lot of cyan. This last method could also work for punching up reds, but by manipulating the magenta channel instead. As with many techniques in Photoshop, there usually isn't only one right approach when a certain end result is desired. |
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Michael McLoone, Photographer
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Cary | NC | USA | Posted: 7:00 PM on 07.15.03 |
->> Ron,
Thanks for the tips.
Michael |
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