Monday, April 19, 2010

Why CMYK PDFs are darker than Pages documents?

Chris Howard, a reader from California, wrote to me:

'I've followed the steps in your blog about converting Pages to high quality PDFs.  Does your work come out a little darker when converting to CMYK?  I'm also in pages 09'

Yes, it does a bit. It is not something to worry about, the print quality will still be good.

I am sure those who studied printing techniques in depth will have a better explanation, but for myself I've developed a simple  way of understanding this. RGB colours (red, green and blue) are for the generated screen light going straight into your eyes, and CMYK colours (cyan, magenta, yellow and black/key) are for the light reflected off the paper - that's how the human eye sees them. You have a desktop lamp, look at the things on your desk - that's reflected light. Now look straight at the lamp. Which is brighter?

It is good to keep this in mind when working on your Pages project: use lighter photos and adjust or avoid vibrant, 'neon' colours that look great on screen, but come out dull on paper.

Check this earlier article on converting Pages projects to CMYK-ready PDFs.
Photo: apple buds ready for spring blossom, © A.Anichkin, 2010

9 comments:

  1. Thank you for this brilliant website. I'm writing a book in Pages and was really stuck on this conversion issue.
    A question. I too am finding outcome Adobe PDF images dark, but, in particular, black and white or Grayscale images seem very dark. Should I adjust these pictures lighter before transferring to postscript. I've only seen them onscreen not printed yet.
    Thanks again

    ReplyDelete
  2. re your question, yes, I would make b/w images as light as reasonably possible, perhaps in iPhoto before importing into Pages (though Pages media browser allows to do it too).

    If you have already chosen printers, it might be a good idea to ask them to make test print-outs from CMYK ready PDFs.

    I have worked with b/w photos within a 4-colour publication and black/grayscale, don't worry, they come out fine.

    Make sure your images are 300 DPI. If they are 72 DPI like many on the internet, reduce dimensions in your Pages document.

    Let me know how it goes please, I am collecting testimonials from Pages users (not just to promote my blog, but to encourage others with similar projects).

    Best wishes,
    Alex

    ReplyDelete
  3. I'm trying to print a book cover designed in pages. I have Adobe Acrobat Pro X, which does not allow one to add Adobe as a printer, so I have not been able to find a way to send my large page to postscript. The postscript file gets trimmed to match the letter size printer I have attached. Apart from being cut in half, it's beautiful! But I have to send my design straight to an Adobe PDF (or save as pdf, then fix for printing: same outcome on this issue). The problem is that my nice bright blue (rather important) lettering becomes a bluish gray (whole design shot!). Is this a real change or a "screen thing"? Can I choose a better blue somehow that will come out as expected in CMYK? Or is there a way to go through postscript with a big page? So so so thankful for any help!!!

    ReplyDelete
  4. Kim, hi,
    there are several questions in one here - adding Adobe as a printer, truncating PDFs and retaining colors.
    Re. colors, yes, CMYK PDFs look darker than the Pages screen version. They are better when printed but, as a general rule of thumb, avoid too dark or too vibrant colors. Difficult to define, but use your good sense.
    I've written on this blog about the truncating (scaling down) PDFs and adding printers. Let me know if you need further help.
    Good luck with your book!
    A.

    ReplyDelete
  5. Hello!
    I like to add shadows to some of my text and to images that have had instant alpha applied. When I create a press quality PDF from the document, Adobe's preflight analysis highlights the shadows as low resolution. When I magnify the PDF 400%, pixelation is visible. My guess is that a low resolution shadow when printed would appear blurry as it ought to, but I wouldn't like to get pixelation. Do you know how shadows print? Or a way to create shadows that pass the 300 dpi test? (I'm aiming to do this in both black and white and full color.)
    Many thanks indeed and best wishes,
    Kim

    ReplyDelete
  6. They print fine, Kim.

    Except when shadows are close to or overlap text. This makes text fuzzy. Just make sure that shadows don't go over the text.

    ReplyDelete
    Replies
    1. Great! What about a shadow that overlaps another photo? Does that work?

      Delete
    2. I am not sure if I've used this in commercial print, but look at the graphics in the title panel of the blog: it's colored shadow overlapping the photo in the back (shadow goes inside off the transparent letters).

      Delete
  7. Thanks a lot for the good ideas and information.

    ReplyDelete

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