Help please! URGENT

[GerardA1969]

I have many PNG transparent RBG images linked in InDesign for a book I'm trying to prepare for prepress. I select these PNGs one at a time and open to convert them in Photoshop into a CMYK image. I do this by selecting "edit" and "converting the profile" to CMKY SWOP2. However, when I resave it, and go back in to InDesign and select and open in up again in Photoshop, the file again shows that it still is an RBG type (it never saved as a CMYK to the same image linked in InDesign). What am I doing wrong?

[Leslie Moak Murray]

Try Image>Mode>CMYK, and when a popup appears, make sure to select "Don't Flatten"

[GerardA1969]

When I "Save as", there is no "Don't Flatten" dialogue that appears. There is a dialogue that says "Layers" which is checked when I save. I might be misunderstanding your steps. Should I be "Saving as" or "Exporting" this updated CMYK file?

[Leslie Moak Murray]

Well, I'm in CS6 so maybe they've changed things, but when I do the steps I gave above - Image>Mode>CMYK -  I get this popup ( I select "Dont Flatten" and then I do "Save As"):

[GerardA1969]

I'm using CC. I even notice that when I do "Save as" it doesn't even give me an option to save it as a transparent PNG. Hmmm.

[marliton]

Hi. Don't use PNG format for prepress, use PSD, TIFF, etc. PNG format doesn't support CMYK color mode.

[GerardA1969]

It worked. Wow. I appreciate you taking a moment out to help me. So my PNGs in my indesign doc number hundreds. So I'm individually clicking and converting, then saving as a PSD. Then I go back in to InDesign and delete the PNG and bring in the PSD file in its place. I wonder if there is an easier way to do this.

[marliton]

Hi. If you use the same images names with a new format, you can use the "Relink file extension" command (inside the menu of the Links panel) for replace all images at the same time: https://helpx.adobe.com/indesign/using/graphics-links.html

[D Fosse]

PNG is a web format, not intended for print. That's why there's no CMYK support.

In any case, placing CMYK images in InDesign is generally not recommended. The CMYK conversion is better performed when you export a press-ready PDF from the InDesign document, and you know the destination CMYK.

The reason for placing RGB in InDesign is that it can then be easily repurposed for changing press conditions and a different destination CMYK profile.

If you are absolutely certain that you have the correct CMYK profile and no other CMYK profiles will ever be relevant, then you can place CMYK. But there's no particular advantage to it either.

What you can do in Photoshop, is proof to the destination CMYK profile. This shows you in real time if you get gamut clipping that you may want to compensate.