Converting RGB to CMYK - should I just leave out transparent images?

[Jonas5CF0]

I'm creating two packages of image files: One with RGB versions of images and another with CMYK versions. Now, half of the images have transparent backgrounds. So my question is, should I just leave these out of the CMYK versions completely? I know you can't save CMYK files as png files with transparency so I thought maybe I'd just convert the transparent RGB images to CMYK in Photoshop and, as the colors now have converted, change them back to RGB and save it as a png. That way, when people print it, the colors won't act up. Or will they?

Does my question make sense? And will it even work the way I imagine/hope it will? Or is it best to just leave the transparent images out of the CMYK package entirely?

[Mylenium]

No, none of this makes any sense. CMYK is a device-dependent color space and arbitrarily converting CMYK colors to RGB serves no purpose, as even if they were created with a specific color profile/ output device in mind, a different device (printer or whatever) would still interpret it differently and mix up the inks. that is the whole point. You may want to educate yourself about this stuff. Point in case: Without full color management any CMYK conversion is meaningless, including proofing on your computer, tagging/ embedding the color profiles and also having whoever does the print also respect this. That being the case, chances are normal RGB will suffices and any subsequent conversion will have to be handled directly by whoever does the actual printing, assuming they actually know what they are doing (which from your question doesn't seem likely, no offense). Either way, if at all, you can convert your images to a generic color profile like one of the FOGRA standards, but that still requires CM on your end. After that they can easily be saved as TIFFs, PDFs or native PSDs with transparency or "correctly" flattened, as that's what people use in professional printing.

Mylenium

[c.pfaffenbichler]

What’s up with trying to provide images for print as png? 

RGB psd are just fine (the profile needs to be embedded naturally). 

[Jonas5CF0]

The packages are sent out to for instance a magazine so they'll be able to use the RGB versions on their website and the CMYK versions in their printed magazine. They might want to be able to place an image with a transparent background in their magazine.

I asked this question because they often request CMYK versions - otherwise I would just send them the RGB versions and let them do with them as they please. Would you still just send them the RGB versions or what would you recommend?

[D Fosse · Accepted solution]

CMYK is for sending directly to offset press. Is that what you're doing? If not, I have no idea why they would want CMYK. It doesn't make any sense unless you know the actual press conditions and know which CMYK profile to use. Do you?

From your description, it sounds like they don't really know what they're doing. I'd ask them again if you may have misunderstood something. If they still insist on CMYK, you absolutely need to know which. This is critical! Don't let them get away without answering. There is no such thing as generic "CMYK", and any CMYK-to-CMYK conversion can rapidly damage the file in various ways.

A magazine is made in a page layout program like InDesign. Placing RGB images in InDesign is the standard way to do this, and if they want transparency, PSD or TIFF with transparency is the way to go. Final conversion to CMYK is done when they make a press-ready PDF from the InDesign file.

PNG would work for the web images, so you could send them that. Or jpeg, depending on content. Jpeg works for photographs, not so well for graphics.

[Jonas5CF0]

Thank you! This was very useful. 🙂

[deborahw14581387]

Then why when I export the PDF file from InDesign, does it give me an ICC error message telling me my images are all RGB.   Why would it bother to tell me that if there is not a problem with just converting at the creation of the PDF?

PS   I know the printer is Indigo and the printer has given me the specific color and PDF file formats preferred. 

[c.pfaffenbichler]

Please provide a meaningful description of your issue. 

What are Indesign’s Color Settings? What are the indd-file’s color settings? Have the images been saved with embedded profiles? etc. 

edit: And naturally: What are the selected pdf settings?