1. You should NEVER open a PDF for editing in Photoshop or Illustrator except PDFs which have been created in those programs. It will destroy font information and as PDFs can have different color spaces it will destroy those also. In Photoshop you get rastereized font, even high resolution will not bring a better quality. Get back to the original file and make the changes there.
2. If you need a greyscale of an existing PDF, go to Acrobat Pro and make it there, it causes not so much damage as doing it in Photoshop.
3. The original PDF has probably some transparency in the content. It causes often 1c images to look flaw, but it is a screen only issue. Does it also change in the overprinting preview in InDesign? If you export it later to PDF/X for print it should not make any issue.
Hi Willi ... thanks for responding.
I do not discount anything you've said, but here's my situation: I get LOTS of PDFs, many of which require some change. Each comes from a different source ... and there is never any circumstance where I will have access to the original ... period. And, although I understand that rasterizing fonts results in lower resolution, the particular jobs I'm working on don't require that level of perfection. All that's necessary is that they be CMYK (or grayscale), using the color spaces I've set up as my default in Photoshop. I prefer working on projects where deluxe quality is paramount, but this ain't it.
I kinda suspect that it's a phenomenon that only exists on my monitor, as you suggest.
I did not say it exists on your monitor only, I said it is a screen issue only and is quite normal when transparency is involved.
But you will not tell me, that you place only CMYK images in InDesign? No? Graphics, ok, but imagages? You should use RGB images. http://indesignsecrets.com/import-rgb-images-indesign-convert-cmyk-export.php
If you need to make changes in a PDF, use Acrobat, not Photoshop. And the rasterizing art would require 4 x so high resolution which causes an amount of 16 x file size to get the same result as vectors.
The article you suggested I read begins by saying that there are still some people who are stuck in the old-fashioned "if it ain't broke, don't fix it" universe, and they're doing things the same way they were doing them in PageMaker 2. (For a brief time, I was a beta-tester for Aldus.) I'm ashamed to admit, they've described exactly who I am. Kinda living in a tech vacuum here. Most people I work with don't know the difference between CMYK and RSVP. I'm going to be STUDYING this article, Willi, and gleaning from it everything I can, and then CHANGING the way I do much of what I do, all credit to YOU, and with my humble gratitude.
So much to learn, so few functioning brain cells.....
I don't want to offend anyone. I am Betatester with Adobe but knew Aldus PageMaker since 1.2 very good. There are some good articles like this one, it will help to work more efficient to read InDesign Secrets.
Not the least bit offended. Anything anyone can do to make me a better human being, I'm extremely grateful.
Just kinda curious if there's any logical explanation for this
InDesign manages the appearance of a grayscale image in two different ways depending on the situation.
When there's no transparency on the page and you have Overprint/Separation preview turned off a grayscale previews as Gamma 2.2 (sGray) and the document's color profiles have no affect on the grayscale's display.
If you turn on Overprint/Sep Preview a grayscale previews as it will print on the CMYK black plate and the document's assigned CMYK profile affects the display—the preview of the grayscale will change depending on the assigned profile. You also get the CMYK black plate preview when you add transparency to the page and the document's Transparency Blend space is CMYK whether Overprint is on or off, which is what's happening in your case.
See these threads: