I'm making a PDF/X-1a, from a CS6 indesign file, for a print magazine that will be illustrated with images of everyday objects. The images are made from scans and photographs. There is no line art and it will be printed by a commercial offset printer.

What is the exact sequence I should use in PS (don't laugh, I use CS3) when changing a PSD or TIFF from RGB to CMYK and flattening all layers?

Currently, if I have a TIFF, I make my layers and tweaks in RGB (because I use the file for Web, too) and then for print I would flatten and then I would switch to CMYK, 8 bits. Is this right, or do I change the image mode first and then flatten second?

I have this same question of proper step sequence when taking a PSD and saving it as TIFF for print output.

If I want to use a PSD for a print magazine (again, I'm only sending the printer a PDF/X-1a) I was told by a graphics friend that I should save it as a TIFF.

When I open a PSD file to save as a TIFF, at what point do I change from RGB to CMYK, when do I flatten? Do I do this first on the PSD side, or on the TIFF side?

When I change from RGB to CMYK, I see a message: "Changing mode will discard some adjustment layers, change them anyway?" I can either hit Merge or OK. Which do I choose?

Also, a PS dialog box asks what image compression, pixel order, byte order and layer compression I want. It defaults to LZW. Do I choose None?

Apologies if my questions are too jumbled. I'm, trying to be clear. Thanks for any insight.

PS Dialog Box

tiff compression settings


2 Answers 2


At best, your "graphics friend" is a bit out of touch with modern workflows. You don't need tiffs or flat files for use with InDesign.


In Photoshop...

  • do whatever to image.....
  • Convert to CMYK
  • color correct after conversion (if necessary)
  • Save as PSD

Then to InDesign...

  • Place layered .psd in InDesign
  • Export to PDF/X using InDesign

You do not need to flatten the Photoshop file and you do not need to save as TIFF. InDesign will read and export layered .psd files just fine.

In fact, you can even avoid converting to CMYK if you desire. The export to PDF/X in InDesign will auto-convert RGB to CMYK based upon profiles.

I, personally, always convert PSD files to CMYK for print projects. I do not want to rely on any automatic color conversion. I'd rather see the CMYK and adjust if needed. But this is more my personal preference. There are many users that just use RGB and let InDesign convert everything when generating a PDFx file.

  • Thanks for your reply. Can I ask, as this project four 4-color offset printing, should I bring in my raw images and and convert immediately to CMYK and edit from there on (leaving all layers alone, as you suggested)? I have always edited the files as RGB and then changed into CMYK at very end. Aug 9, 2022 at 17:04
  • 1
    @regretagarbanzo You can work in RGB. I convert to CMYK as a final step. Actually I save the RGB file.... then convert to CMYK and save with a different name for use in the layout. That way I still have all the RGB data present should I need to edit the image in the future. The only thing I'll do after CMYK conversion is color correct if necessary. But.. this is merely my workflow. I have no problem maintaining 2 files for something - one RGB and one CMYK.
    – Scott
    Aug 9, 2022 at 17:07
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    As you've mentioned in the question... sometimes it's necessary to merge adjustment layers when converting to a different color mode (CMYK).. that's why I maintain the original RGB file as well. CMYK file is strictly for placement in INDD and output. If any changes are needed to the image itself, I go back to the RGB file, make changes, save, then re-save as different name and re-convert to CMYK.
    – Scott
    Aug 9, 2022 at 17:10
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    Truth is, you may be apprehensive about all this unnecessarily. Even if you were to just place the RGB fie in INDD, the PDFx output will convert it to CMYK. If your color profiles and calibrations are good that auto-conversion is generally not terrible and will often suffice. Ultimately it boils down to how meticulous you are (or want to be) regarding color accuracy.
    – Scott
    Aug 9, 2022 at 17:14
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    @regretagarbanzo To maintain any adjustments that Adjustment Layers are performing, you'll want to merge. Which is why keeping the original RGB file can handy - so you can go back and tweak adjustments if needed.
    – Scott
    Aug 9, 2022 at 17:44

There is no exact sequence. There are just many alternate paths you can take each with their own trade-offs.

Sometimes the math in cmyk works a bit different, so you may want to selectively flatten things before conversion. The reason you wouldn't flatten all just essentially for ease of editability.

However, if you dont intend to adjust your image after the conversion you might, as well not bother at all, indesign will do this for you. Essentially indesign would do a flatten and profile to profile conversion. Though you may want to convert purely for preview purposes.

As for saving a tiff file? Depends, the only reason to save a tiff is if you want to archive a adobe independent version of the file. But since the tiff likely has quite many adobe extensions you should verify it works in your dowstream application. If your targetting indesign then not much point in doing so. Therefore we can't advice on the options it depends on the dowstream application.

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