Enfocus Community

We have received a pdf fil from a custom for a black and white job.
However when we send it to our Indigo presses some pages become four color and some become black and white.
We have converted the entire document to grayscale, but still there are a couple of Warning icons that are converted to CMYK even though they are defined as grayscale.
If I look in the inspector I can see that the Blending color space for the transparency group is set to RGB, which I suspect is causing the problem.
Is there a way to change this?

That is indeed your problem.There is an Action "Change blending color space" with an option to set it to "None" so you have an easy fix. Just do that with a "Select all" to make sure you change them all (there may be more than you expect, see below).

Some background. A blending color space is the color space of the final result, so all objects are converted to the blending color space of the container they are part of. That container can be a form or a page. Consider the case of a CMYK object in a form with a gray blending color space on a page with an RGB blending color space. When interpreting the file the CMYK object will be converted to gray because of the form's blending color space and then to RGB because of the page's color space.

You could use this property for example as an easy "trick" to convert a page to black and white: just set the blending color space of the page to gray. This method supposes, however, that the rip honors the blending color space of the page; that is not always the case. And for people using the PitStop Inspector it can be confusing because the objects look black and white but their definition is not.

Blending color spaces are always a guarantee for some fun.