I am not sure if this is the right place to ask my question. My department is constantly working with multichannel documents. I find myself now needing to be abe to create my own custom ".acb" files containing color values that I have corrected for our own purposes. However, there is almost no documentation about this. I have written a MAC OSX native application for developing ".acf" color libraries for use in other applications. It let's you assign RGB and CMYK values to a specific spot color. In essence, it let's you display PANTONE colors on screen with the proper RGB values, but converts them to the closest CMYK match when printing. The only reason I am telling you this, is because I am willing to trade my application (and all source code) for any useful information regarding how to create a custom ".acb" color book for Photoshop on a MAC.