Troubleshooting Color: Source Colorspace Designation

More than once I have been asked: "OK, so the color is wrong, how do I make it right?"

Troubleshooting CMYK color can be a pain, because there are often many places the problem could be lurking, and changes made in one, may inadvertently alter the output based on info from another. So in this five part series, we will look at five important steps to troubleshooting a color managed system, or colorimetric tuning.

As you all know, a color management system is usually broken into five parts:

1. Source color space
2. Media parameter setup
3. Source color space designation
4. Output color profile
5. Output calibration set

As we have discussed, the source colorspace is crucial to determining how the system should translate from the input color to the output color, via command given to the rendering engine. Without knowing where you start from, it is difficult to navigate where you wish to be.

The color space and variant used to create the job must be designated in the RIP's job parameters. If you know with certainty the input color space, you can define it explicitly. If you do not have this information, most operators use sRGB, since it is the smallest of the RGB input color spaces, and thus the lowest common denominator.

Most RIPs allow you to recognize if a given file has input profile information embedded in the file. If present, this information gives you the best chance of output that matches what the file's creator intended.

Almost every file has some CM information present. Even if the original creator of the file was not prepress proficient, Adobe Creative Suite automatically embeds color input info when saving files. Should someone convert from RGB to CMYK in Photoshop, for example, the file is now in GRACoL CMYK, since that is Adobe's default. Honoring this embedded information is the best way to ensure you are printing to the original creator's intent. It is up to the operator to ensure that this embedded data gets honored.

The easiest and most consistent way to do this is the Use Embedded Profile When Present selection in the color setup tab of the job's parameters which is only effective when the job contains an embedded tag/profile. This is usually the first item to check when printed colors are significantly different than expectations. 

A few troubleshooting hints:

• AdobeRGB jobs printed as sRGB appear flat.
• sRGB jobs printed as AdobeRGB appear too dense with high chroma.
• Flesh tones in GRACol/SWOP jobs printed as ISO (System 7 default) appear rather sun burnt.

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Do you have a color management question, horror story or event to share?

Email me at reilley4color@gmail.com