A customer identifies a problem...

I have a customer that receives tens of thousands of transpromo PDF pages a day for printing (mostly statements, bills, notices and the like filled with ads and other colorful elements). These pages come in groups from various sources along with meta data for mail sort processing.

The problem is that the color space is different in each file.

By this I mean that for one set of files someone was shown a set of proofs on an unknown paper in unknown lighting conditions using values for CMYK or RGB that "looked good". This same process with different paper, lighting, etc. was done for all the sets of PDF pages.

The problem I was asked to solve is "How do we print these jobs out every day and make sure the color is acceptable to the customer?"

There are some considerations that make this problem easier than it might be. First off the color issues are relatively predictable, i.e., a logo has bad color or the green bar across the page is wrong, that sort of thing - we are not talking about pages of full color images. There are images on the pages - but mostly as parts of ads.

We began work on this project about 3 or 4 years ago. At the time the requirements for "fixing" the color were simple - one logo or a color here or there.

Of course the usual "use ICC profiles" was mentioned but that was a miserable failure for several reasons: First the work force is untrained in color and has a primarily black and white mailing background. Second the source material was out of their control. Third there was no concept of monitoring the color during production.

Another requirement was that the files could have up to 100,000 pages so PDF utilities for "fixing color" did not work.