The Acrobat conversion will indeed make a grayscale (one color) file. These settings will give you a starting point: Advanced> print production> convert colors> document colors- device cmyk: convert> action: convert> profile: gray gamma 1.6> blending profile> device gray> conversion options> don't embed profile.
To check your grayscale PDF, use the output preview (print production> output preview) and toggle the black sep. on and off. Another option is to use Pitstop.
I tried this in acrobat 7 and some of the black builds still don't convert. It's probably just another problem that was addressed with the new CS3, hence the reason there is gamma 1.6 in acrobat 8 and not 7. I'm trying to convert a 33 page pdf booklet that a lady sent to me. Unfortunately adobe made this option available but not fully functional, which sucks because explaining to her what the problem with her pdf is much harder and more time consuming than converting it to grayscale myself.
I have this problem too - some objects doesn't convert. I used Acrobat 7 some old version - it worked fine, but updated it to 7.1 - now it leaves some objects CMYK. When I try to edit those objects in Photoshop - it gives me a warning: "Could not complete your request because a colour was specified using an unsupported colour space". With the old Acrobat all I had to do is to take this object to another page (I have an "empty" file specially for this task), convert it there to SWOPv2 for example - and I was able to work with it from there. Now it doesn't convert anymore.
I am afraid it's something with color settings - that's scary because I don't understand much in it, it's so complicated - because when I took one of those files on another machine and tried to open this "problem" object - it opened in Photoshop without problems (CS3) and showed that it is... Grayscale!
Please, help, any ideas? I need to fix up to 20 files every day...
Thank you in advance
With pdfToolbox from callas (check out the pdfColorConvert feature) it is a one click operation that works each time (and neither requires the use of arcane gamma value profiles nor any configuration). Black will and up on black plate only, and 100% (or more) black will come out as 100% black. Demo available at www.callassoftware.com. Apologies for the shameless plug.
I had some trouble with this same issue of converting a color pdf to grayscale. I realized that in my particular pdf, just using the Tools/Print Production/Convert Colors function was not enough. Somehow there were extra spot colors inadvertently added to the file. Here are the steps to follow to make sure this works correctly if you are wanting to convert the entire pdf file to a grayscale image:
(I am using Acrobat 7.0.9 on a Mac OS X, 10.4.11 system)
1.) In your pdf file go to Tools/Print Production/Ink Manager click on the bottom left corner box that says (Convert all spots to process). Click okay.
2.) Go back to Tools/Print Production/Convert Colors. Click on (Device Gray: Convert) Action: Convert. Profile: Select your profile of choosing....for me it was 10% Dot Gain way at the bottom). Convert Pages: All. Conversion Options: Don't Embed Profile. Check box that says, Preserve Black Objects. Click okay.
This should resolve any problems with those extra colors that will not convert to grayscale since they are assigned as spot colors.
Hope this helps. Let me know if this works for anyone. just tried it once.