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Matt Hodges
Known Participant
November 2, 2012
Question

Do I need to convert my images to CMYK in Photoshop?

  • November 2, 2012
  • 1 reply
  • 39495 views

Hello

I've been designing printed materials for a while now. In the past I always used to convert my images to CMYK in Photoshop before sending a job to print, because usually I would be supplying packaged artwork (Pagemaker/Quark/Indesign) to my printer.

These days however, 99% of the time I would be supplying a print-quality PDF exported from Indesign. I understand that with the right settings, Indesign will convert the images from RGB to CMYK when exporting, making the resulting PDF suitable for 4-colour printing. Out of habit though, I still convert the colour space of my images manually in Photoshop before exporting.

So my question is, is there any advantage in doing the colour conversion manually using Photoshop? Obviously this process is time-consuming, and also reults in twice the number of images assuming that you save a copy of each image (the CMYK files have larger file sizes as well). Does it make any difference to the 'quality' of the images in the final PDF? And therefore does it make any difference to the final printed document?

Apologies if this question has been asked before – I can find plenty of discussion around the topic, but no explanation as to whether there is any real benefit (in terms of overall quality) to using either method.

Thanks.

1 reply

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bret_linford10607319
Known Participant
November 2, 2012

If you are converting your pdf to  the same cmyk color space as you have been converting the individual images in the past, there is no advantage. You will be doing the same thing and saving time by doing this in the coversion to pdf.

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SasquatchPatch
Participating Frequently
November 4, 2012

If all you're doing is converting is just converting, then the result will be the same, but if you're interested in quality, you can almost always do post conversion tweaks that improve the image. And some images are better with Relative Colorimetric while others might need Perceptual rendering intent. Some might need a heavier or lighter black plate.  And then there's sharpening. Sharpening should be done in CMYK at the final size for the best results. My normal workflow is to design in RGB, then convert all files to CMYK, then resize so they import at 100 percent and sharpen them as needed. Yeah, it's extra work, but it really pays off when you see the job coming off the press. What's right for you depends on how picky you or your clients are and if you need to squeeze that last bit of image quality out of your files. If "good enough" is okay for you, then the convert on export route might be fine.

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Anonymous
November 5, 2012

Thanks for the advice. To be honest, I don't generally do a huge amount of image adjustment (in fact, you say "some images are better with Relative Colorimetric while others might need Perceptual rendering intent" – I don't know what this means, which might give you an indication of the level I'm working at). Where an image comes to me from a photographer, I often assume (perhaps wrongly) that any adjustments to the image have already been made by them, and that they wouldn't appreciate me doing anything further.

Now I think about it, I should probably do some research/learning with regard to optimizing images for print using Photoshop – the main focus of my work is on layout and typography, to the point where I am probably reglecting this area.


What could help:

-Synchronize all application to the same color settings (be sure to select the proper Color Settings first -> 'Europe Prepress 3' if you're located in the EU for instance)

- Keep your images in RGB

- Place the RGB images in InDesign

- Export to PDF using proper PDF export settings (PDF/X-1a if it has to flattened (PDF1.3), PDF/X-4 if you want to keep live transparency)

- Never forget to 'live preflight' your document before converting it to PDF or sending it to your Print Service Provider btw :-): http://www.vigc.org/standard-preflight-profiles/

This approach assumes of course that you are content with the standard ICC based color conversion that InDesign will do for you during PDF conversion (similar to the color conversions you did in Photoshop) and that no manual tweaking of images is required to achieve better image quality afterwards.

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