RGB--->CMYK

[detritus books]

I got sent a bunch of RGB images for a print job, that I need to convert to CMYK. My PS skills are far less than my InDesign skills, so when I tried to convert images to CMYK, and got a message that said "Changing modes will discard some adjustment layers; change mode anyway?" I was a little confused. What "adjustment layers" will be discarded? Will this effect the appearance of the image? Mac/CC

[mglush]

Hi!

Can you show a screenshot of your image and window with the layers panel visible? That would help us see any adjustment layers.

But, second, I work in PS and ID and I bring my RGB psd files right into into InDesign and let InDesign make the conversion when I Export the file to a PDF for print. Have you tried that, and is there a reason why you would not want to? Just make sure you put the correct output profile when you Export and the conversion works well.

Upload the screenshot when you have a chance so we can see what the error message is referring to.

Michelle

[detritus books]

[detritus books]

Cool, there's the screenshots. Somehow I've never heard of just letting InDesign do the conversion? I have no idea why not to (I'm self taught, so have learned to do a lot of things the hard way).

[mglush]

Ok, from your screenshots (cool image BTW!), I don't see any adjustment layers, so I don't think you have to worry about that. But, I think I would still recommend using your RGB image in InDesign and test to see if you are happy with the conversion. That way you keep your image in the RGB color space and don't loose any color information.

So, place your .psd file in InDesign and make whatever size adjustments you need. If you need to make any changes to the .psd file, you can make them in Photoshop and then update the placed file in the Links panel by clicking on the yellow warning triangle next to the file name.

When you are ready to send your file to print, choose Export from the File menu and in the Output panel, choose your destination profile -- these can get complicated but I've found I get good results with US Sheetfed Coated and US Sheetfed Uncoated depending of the paper you want to print on. You can play with some of the other options once you feel comfortable with using the PDF dialog box. See the screenshot below.

Do a test to see if  you are happy with the conversion and let us know if we can help!

Michelle

[detritus books]

Thanks! I've got about a dozen more images in this document, what would show me if there were adjustment layers in the others?

[mglush]

You would see something like this in your layer's panel:

This is a Curves adjustment layer with a mask--your adjustment layer mask may have something in the mask or may not.

Do you see anything with a little Adjustment icon in your Layer's panel?

Michelle

[D Fosse]

Just to be clear, the output CMYK profile is not something to experiment with. You need to set the correct profile, the one that corresponds to the actual process/paper/ink in use.

You always need to ask the printer. Offset presses are calibrated to different standards around the world.

This, BTW, is why you place RGB in InDesign. Then it can easily be repurposed for different print processes.

[mglush]

Absolutely. But he had never done a conversion in InDesign before--that is what I was suggesting to experiment with.

[jane-e]

https://forums.adobe.com/people/detritus+books  wrote

Somehow I've never heard of just letting InDesign do the conversion? I have no idea why not to

Hi,

Read this post from David and Claudia on InDesign Secrets for details:

https://indesignsecrets.com/import-rgb-images-indesign-convert-cmyk-export.php

InDesign Secrets has some parts for paid members and some parts that are available for all — I’m not sure where this is, as I am a paid member.

Both have titles on LinkedInLearning (was lynda.com) on pdfs from InDesign.

Jane

[Joely]

You can use the RGB pictures within Indesign, no problem in the age of «media neutral workflows». But pay attention when you export to PDF. or Package the editable Indesign Files for print-production.

You can also make a badge processing with Photoshop to flatten the images to TIFF and CMYK, or only flatten.

Good luck.

[Bob_Hallam]

Just a quick note to say that your choice of CMYK profiles to convert to is very important.  Do not use any of the recommendations in this thread without speaking to your printer and find out what profile they need you to use.  As I have worked in the printing field and have worked for big box sheetfed, web-fed and gravure printers, it is very clear from that experience that how files are converted matters.

In the case of sheetfed printing, those printers will use a very specific profile.  In North America and China that will be GraCol 2013 or ISO15339-RPC-6.  Not using those for sheetfed work limits color in the shadows and can actually remove detail that the printing process would normally carry.  In Europe it's Fogra-39-011707.   So do ask what your printer prefers and follow their guidelines. 

Some printers may even provide their own ICC profiles, and some may prefer to have RGB images and do what's called "Late binding CMYK" which converts those files on the fly as they move through the workflow. 

[D Fosse]

Bob_Hallam  wrote

In Europe it's Fogra-39-011707.

The de facto standard in Europe now - or at least the most widely used - is ISO Coated v2 300% (ECI). It's based on the FOGRA39 characterization sets, but different black generation and TAC.

(Edit - note that this profile is not included in the Photoshop installation, so it has to be downloaded and installed separately).

IOW you can use the FOGRA39 profile and probably get the same result visually, but the ink limit may possibly cause drying/smearing issues and other technical problems.

There are some new standards out by now, but so far I haven't been asked for that, so I stick with ISO Coated v2 300% (ECI) until I hear otherwise.

[Bob_Hallam]

You are correct the longer black in ISO Coated is best, but again the point is that the OP checks with the printer for their recommendation. 

[D Fosse]

Absolutely

[detritus books]

Thanks everyone. This is all interesting because the printer I've been using for years has me convert all images to CMYK without letting InDesign do the conversion. They just have a specific export profile that I use. But, I'm about to use a different printer for the first time, so I'll make sure to ask them what they prefer!