1 Reply Latest reply on Oct 30, 2008 3:01 PM by (Marco_Ugolini)

    Best Workflow for Rich Grayscale Images on Press

    It'sNotMyFault Level 1
      Hi, we're preparing a piece that uses mostly grayscale images and we want them to look as nice and rich as possible. So wondering about proper workflow to convert the images to CMYK using best percentages for nice, rich shadows, etc.

      What I've done so far is:
      1) Got a photo looking pretty decent as a grayscale image.

      2) Convert the image to CMYK using a custom profile I created similar to 'SWOP, 20%, GCR, Heavy' - except that I manually adjusted the Black Generation curve to remove most of the CMY from the highlight areas.

      3) Do any final levels adjustments to get the photo just right.

      4) Save the file embedding the profile.

      Now the photo looks good in Photoshop, and is very neutral (what we want). The darkest shadow areas are 95%-99% black, but with a good 40, 30, 30 mix of CMY. The highlight areas are black only up to about 16%, then color starts creeping in at proper ratios.

      NOW I'M A BIT FUZZY.

      - When I drop the photo into InDesign, the Prepress defaults strip the profile and convert to US Web Coated SWOP, BUT preserves the numbers. The photo takes on a cooler, more blueish tint. Is this to be expected?

      - We may not know the printer of the job ahead of time, and even if we do I've found many who don't fully understand color management and don't have a custom profile for their printer. What is safest in this case?

      - If we do get lucky and find out who the printer is, and they have a printer profile, how would we implement this?

      - Any other tips???

      THANKS!
        • 1. Re: Best Workflow for Rich Grayscale Images on Press
          (Marco_Ugolini) Level 1
          This may not be the most appropriate forum for your question. The separation you are using is done using the Custom CMYK engine, which is a legacy (pre-CM) mechanism in Photoshop that has no direct relationship to ICC color-managed workflows. Legacy questions may be better addressed to other forums.

          On the other hand, if, rather than use the Custom CMYK engine, you wish to separate your grayscale image to a CMYK ICC profile appropriate to your output conditions, the procedures are clearly outlined in "Real World Color Management", by Bruce Fraser, Chris Murphy and Fred Bunting. (Look for it on the Amazon site.)

          When the output conditions are not known, make sure to speak to the printers once they have been picked, and clearly communicate to them your concerns. You can provide a CMYK image file separated for US Web Coated (SWOP) v2, and ask them to reseparate it appropriately for their own press conditions. You could also provide the grayscale file, if they would rather have that one. In any case, make sure to tell them that you are looking for a high GCR.

          It's also a good idea to send them a properly color-managed proof (aimed at US Web Coated (SWOP) v2), and tell them to make sure to match it. Other than that, and in the absence of any information that is more detailed and specific, there's not much else you can do.
          >When I drop the photo into InDesign, the Prepress defaults strip the profile and convert to US Web Coated SWOP, BUT preserves the numbers. The photo takes on a cooler, more blueish tint. Is this to be expected?

          InDesign is
          i not
          converting the image. The North America Prepress 2 color presets use the "Preserve Numbers (Ignore Linked Profiles)" policy for CMYK. This policy
          i ignores
          the CMYK profile embedded in the image and
          i assigns
          the default CMYK profile instead. The image numbers are left untouched, but the appearance changes because the default profile (U.S. Web Coated (SWOP) v2) describes print conditions that differ from those established in your Custom CMYK profile.