PDF With Color and Grayscale Images Prints 4-Color Grayscale

There are many places in the print chain where the GS->CMYK change can happen, so the first thing to establish is if the images in the PDF are actually using 4 plates. In Acrobat Pro, use the Output Preview inspector (menu..advanced..print production) to look at the images in question by hovering about with your mouse - you can filter by types of object etc. so you're only looking at the images, then look again with everything visible.If the images are in grayscale but there's something over/underneath that's in CMYK (even if it's white or transparent) then the process of rasterising the page (done by the printer driver) can often merge the spaces.

If the images are CMYK in the PDF, then either you're using a preset in Distiller that converts everything into CMYK (the PDF/X-1a:2001 preset does this for example), or the Postscript output from Publisher is being sent in that space. Publisher 2003 has a bug that treats 8-bit GS images as if they were CMYK; the fix is at this link:

http://support.microsoft.com/kb/819584


Acrobat Pro has a Convert Colors tool (advanced..print production) but it's not too helpful as you can't apply it to a single object, only a class of objects on a page (so you'd convert every image) - so the only realistic option is to track down where the change is happening and fix it there.

I am experiencing similar issues. I work for a printing company. We are having problems with one of our smaller inkjet printers. When sending a PDF that contains greyscale and color images, the greyscale images print in 4 color. I can adjust the color settings at the printer to "no profile." This will print the greyscale images in greyscale, and the 4 color images in 4 color. The problem with this though is that the color images look horrible, being they aren't being assigned a specific profile.

If I adjust the profile for RGB (to adobe 1998, for example), there are minor changes to the RGB images, but the CMYK images still look bad. By changing the CMYK profile(to US Web coated (SWOP) v2, for example), the color in the CMYK images improves, but the greyscale images print in 4 color again.

So, how can I export a PDF (I'm using ID CS5) with greyscale and 4 color images, and have it print the greyscale images greyscale and the 4 color images in 4 color?

Any help would be great. Thanks,

Dan

This is a time when having Enfocus PitStop or callas pdfToolbox will help. Depending on the version of Publisher everything will come out RGB. If it's Publisher 2010 then "gray" objects should come out as device gray. But... We also need to know if Microsoft's advice of using their printing tools to convert the publication to CMYK were followed. I have found it best to leave everything RGB in Publisher and save a PDF or print to the Adobe PDF printer using the "high quality" options. Publisher (Windows GDI) uses sRGB as its RGB space and Publisher also has its own old Agfa based SWOP ICC profile. Which would explain why the CMYK seps from Publisher look so good...

I don't believe that Distiller or Acrobat Pro are smart enough (even with preserve black objects turned ON) to convert RGB gray images (specifically images) to grayscale. I know PitStop isn't but callas pdfToolbox is. For the most part you can take care of everything in Acrobat Pro by converting to CMYK and using the preserve black objects button. If you want to go further then tools like Enfocus PitStop and callas pdfToolbox will prove to be invaluable. callas has a few advantages, PitStop has a few advantages. But both will get the job done. If you do decide to do it all in Acrobat Pro you will want to use the separation preview as was suggested but also the object browser. Object browser will show you what each objects properties are (RGB, gray, CMYK, 72 dpi vs 762 dpi, overprint status and stacking order, etc). Once the colors have been converted using the convert colors or the preflight tools (my preference) you can use the touch-up object tool to edit the images with PhotoShop to get them back to grayscale (or at least into the black channel of CMYK). PitStop makes that a bit of an easier process since you can directly manipulate the object in Acrobat and convert to grayscale. Just make sure that you have the color management preferences set correctly. Otherwise it won't turn out so nice. Which is where callas has an upper hand. It doesn't need as much careful tuning to get "more correct" conversions.

SO the short answer is there is no easy way of doing this. The long answer is that it can be made easier if you are forewarned with a few bits of information and have one or two extra tools to make it much less difficult.