PDF will not export because PNGs are in RGB

Hi @landscape_snarkitect , can you show a capture of your PDF Export>Output tab, or let us know what the Destination profile is set to?

I don’t think V4 RGB profiles will trigger the warning—I only get it when the conversion Destination profile is a version 4 CMYK profile (e.g. Coated GRACoL 2013). Also the warning shouldn’t stop the export, the CMYK profile in Acrobat will be listed as Modified.

If the export is failing it is likely for some other reason.

If you are on OSX you can check the version of any profile using ColorSync Utility—the problem could be your destination CMYK profile:

there are a few I cannot convert because they need to be transparent PNGs.

There shouldn’t be a problem using Photoshop’s Convert to Profile to make a conversion into any RGB space and keep the transparency

Have you been able to isolate that it is for sure one of the PNGs causing the issue? What profile do you have assigned to it? (What does your Links show as ICC profiles for the troublesome file(s).)

Typically, by default, PNGs are either sRGB or not managed at all, in which, in the latter case, InDesign will assign the document's default profile as set in your Color settings.

I know of a couple of well used profiles that are version 4 and tend to be problematic: Display P3 is one, which is a widely used Apple ICC profile. Still, if you were to open all your PNGs and reassign a different profile, you should be able to sail through (fyi: The RGB swatches aren't doing it.)

Also: I suggest you instead save those files as .PSD instead. In the end, you have better control of them.

In most cases, the v4 to v2 error message usually will not abort the export to PDF, so there may be something that didn't work in the conversion to v2

Export could convert to CMYK fine. But the message isn't about PNGs, as files, but about profiles 

1. It's a warning. You can ignore it.

2. Otherwise, check the profiles embedded in your PNG files. I think it may be a Mac monitor profile, which is asking for trouble...

PNG's cannot be CMYK, I always convert to PSD's and convert in Photoshop to CMYK. 

This might be the problem as it cannot convert a PNG to CMYK and it needs a different file type that supports CMYK.