How to batch convert RGB images to CMYK

[Justin_Tinianov]

Hello,

Can anyone explain in a step-by-step way how to batch-convert many RGB images to CMYK?

Thanks in advance

[Guest]

We convert from RGB to CMYK to control the balance of ink for printing. If you are performing a batch operation, you exercise no distinct control and the mass conversion of individual images to CMYK may be pointless.

A page layout program like InDesign can accept RGB images and then produce CMYK output in one simple operation.

[Justin_Tinianov]

Sorry, I don't understand. We currently build the book in InDesign, then

convert hundreds of images to CMYK one-by-one in Photoshop, then output a

Press Ready PDF and send it to the printer. Are you saying InDesign can do

this in one step?

[Jongware]

It's not really an operation inside InDesign, but on exporting to PDF, you can choose to output everything to CMYK. Look in the PDF Export dialog.

[Justin_Tinianov]

My printer suggested it's not a good idea to let Acrobat convert the files, it's always better to do it in the native (Photoshop) application. Often when Acrobat or InDesign does it the images end up looking not quite as good as when Photoshop converts them.

[Guest]

The same color conversion engine is used in Adobe apps.  I'm confused why your printer did not suggest exporting a CMYK PDF file from InDesign. Printers, of all people, would know this capability.

EDIT: Here's a very exhaustive discussion in the InDesign forum about conversion...

http://forums.adobe.com/message/2178245

[Grosart]

Absolutely correct - whilst the colour conversion engine is common across Adobe apps, the colour LUT used by Photoshop is superior to the default engine - it's a curious thing (a bit like in the 80's when photoshop's resoutions were in dpi!!!)

[s_mahn · Accepted solution]

If you do want to use Photoshop for the bact conversion there are a few ways, including Batch and Image Procesor under the File>Automate or File>Scripts of PS.

However, my preference is to use Russell Brown's script: Image Processsor Pro, via Bridge:

http://www.russellbrown.com/scripts.html

As similar one is Picture Processor:

http://www.scriptsrus.talktalk.net/

Both allow you to do multiple conversions simultaneously, to different sizes and file types, and running actions before or after the conversions.

[SPL72]

Unfortunately on a mac ayt leadst there is NO default RGB to CMYK conversion action. Its just not part of PS. I can't undertsnad why people sare saying, "yeah for batch RGB to CMYK coversion, go in PS and in the File>Automate>Batch

Its just not there...  

[Conrad C]

Going straight to Batch is not exactly what was said. For example, Jeff Schewe’s reply to this thread 12 years ago says:

In simple terms, you record an action doing a Convert To Profile command in Photoshop. Then you use that action to run a Batch Process either from Photoshop or from within Bridge. The actual step by step is a bit more complicated of course, but what you should first read up on are how to record actions (in the Help) and then how to do a Batch.

By @Jeff Schewe

So he’s telling you what a lot of us would say: Record the Convert to Profile command yourself first. Because there is no built-in action for converting RGB to CMYK.

And there is good reason why there is not. Even more true today than 12 years ago, to correctly convert RGB to CMYK, you want to convert using the CMYK profile that represents the exact printing conditions, as well as properly setting the other options correctly such as Rendering Intent. A default would just be some arbitrary CMYK profile that might or might not make your job look good on the press it will be printed on, and that might waste paper and ink, time and money.

So it’s recommended that you first record that action yourself, as Jeff said, so that the profile and other settings are appropriate for your job’s requirements. Then you include your action in a Batch command, and that will get the job done.

For the same reason (to avoid a generic conversion CMYK that might be wrong), in the years since this thread was started, Adobe added an “are you sure?” type of warning to Image > Image Mode > CMYK to warn people away from doing a generic conversion to CMYK, directing them to, once again, set it up properly in Edit > Convert to Profile.

[Jeff Schewe]

Justin Tinianov wrote:

Can anyone explain in a step-by-step way how to batch-convert many RGB images to CMYK?

In simple terms, you record an action doing a Convert To Profile command in Photoshop. Then you use that action to run a Batch Process either from Photoshop or from within Bridge. The actual step by step is a bit more complicated of course, but what you should first read up on are how to record actions (in the Help) and then how to do a Batch.

[Linda24415233u1d0]

the best and fastest way is to create an action, change all the elements you want, and save it. then go to file > automate > batch. Select your folder, select your action, and run it. it works great. you can even change the file type by including it in the action. very handy. very easy. no script needed. anyone can do it.