I've been sent a pdf which contains text, vector shapes and rasterised images. I would like to take a small area of that pdf, which contains all of these, run that area though Photoshop so I can use a custom photoshop filter on it, and then take the resulting image and put it back in the original pdf.
I can open the pdf in Photoshop. That requires the whole thing to be rasterised. I can specify RBG or CMYK at that stage, and I open it in RGB-8 Adobe-1998 in Photoshop. I crop the image down to just the area I want to change. I then need to save that image out in a format that Acrobat (which I'm using to put the pdf back together) can recognise. Acrobat doesn't seem to like .psd images. However I save the image out of Photoshop, I struggle to get the same color values when I eventually insert it back into my pdf. Color values shift by more than I'd expect, despite everything having embedded profiles.
Is there a workflow that will allow me to rasterise part of a composite pdf, run it through Photoshop, and then embed that rasterised image back in the original pdf, without getting uncontrollable color shifts? I don't mind the odd 1 or 2 shift in 8-bit color value, but I'm getting much more than that. I don't have any control over the color representation of the original pdf but I can set the Photoshop up any way I want. I'm also not restricted to Acrobat. But I do need a controlled and predictable workflow.