Request for CMYK


Today’s Question: A publisher has asked for images to be submitted in “CMYK (no spot colors)”. I’m aware that CMYK is mainly an issue for publishers, but what does this mean for the photographer who is submitting work to the printer? Specifically, does this require any changes in camera settings before capturing the image or in generating the image file in post processing?

Tim’s Quick Answer: If you will ultimately need to deliver files in the CMYK color space (such as for printing), you don’t need to make any changes in-camera at the time of capture. The CMYK conversion would simply be the final step in post-processing before sending the files to the printer. Note, however, that in general I recommend not converting to CMYK, leaving that step to the printer if at all possible.

More Detail: Most photographers, I suspect, are familiar at least in concept with the RGB color space. This is a common color space for recording color values based on emitted light, based on how much red, green, and blue light must be combined to create a particular color at a specific brightness level.

Another common color space that photographers might be less familiar with is CMYK. This color space is specifically designed for print applications, since it is based on the percentage of maximum ink amounts to be applied to paper (or another substrate) for cyan, magenta, yellow, and black ink.

With commercial printing (such as for books) the files being used as the basis of a print generally must be converted to the CMYK color space. The challenge is that for CMYK output, you really need to make sure you are converting to CMYK based on an ICC color profile that is specifically created for the particular output conditions, such as the type of paper being printed to.

Because of the importance of the specific details of how an image is converted to CMYK, I highly recommend asking the printer for an ICC profile you should use for the conversion, and for any special instructions about adjustments that should be applied, such as the specific black point and white point values to use for the image.