Do you remember what your mom used to say when you’d insist, “all my other friends are doing it”? She’d reply, “if they all jumped off a bridge, would you follow them?”
And it’s the same when we consider the question of RGB workflow in a CMYK printing process. For whenever someone insists that they should convert their color images to CMYK in Photoshop before importing into InDesign—“after all, that’s what we’ve always done; that’s what all my colleagues do”—I wonder why these people are so quick to jump off that bridge without first thinking it through.
I want to be clear: There are times when you do want to convert to CMYK first! But the proper response (both to your mom and to the idea of converting to CMYK in Photoshop) should be: “I would stop, consider the pros and cons, ask advice, and then make my own decision.”
Claudia McCue and I wrote an article at InDesignSecrets about the pros and cons of importing RGB images into InDesign (spoiler alert: you should use RGB for most images). But there continues to be confusion about exactly what steps you should take when using RGB images. This brief step-by-step RGB workflow will take you from Photoshop to final PDF—even a CMYK PDF if your printer demands it—by way of your InDesign layout.
1. Start in Photoshop
Remember that every digital image starts in the RGB format. If someone sends you an image in CMYK format, you should probably leave it in CMYK (there’s rarely a good reason to convert back to RGB). But assuming you have an RGB image, open it in Photoshop first.
If you know approximately what size the image will be on your InDesign page, it’s best to crop the image (using the Crop tool) and use Image > Image Size to adjust the image resolution. If your document will be printed, choose an image resolution of about 1.5 times your printer halftone screen. For example, if you’re printing at 150 lpi, you probably don’t need your image resolution to be more than 225 ppi. Note, however, that if you enlarge the image after placing it in InDesign, the image resolution will drop. To give myself some flexibility, I usually round up to 250 ppi for images that are destined for print. (The old 300-ppi guideline is fine, but usually results in images far larger than necessary.)
After you adjust your image resolution, you may need to apply a little sharpening to bring the image quality back up.
2. Soft Proof your Images
While you’re still in Photoshop, you can adjust tone and color. (Do yourself a big favor and learn to use Adjustment Layers or the Smart Filters and the Camera Raw filter for this, so you can safely make additional changes later.) Remember that your image will end up as CMYK sooner or later. Fortunately, Photoshop can preview how your image will appear in CMYK without your having to actually convert it.
This is called “soft proofing.”
To soft proof your document, first choose View > Proof Setup > Custom. Choose the output target profile from the Device to Simulate pop-up menu. For example, if your printer has sent you an ICC profile that describes their printing press and the paper stock you’ll be printing on, you can choose it here. (You would need to install it first, outside of Photoshop.) Alternatively, if your printer has told you to target a standard such as Coated GRACoL, then choose that. Also, you probably want to turn on the Simulate Paper Color option; colors will appear even more “dull,” but they’ll be more realistic.
You can still edit your image while previewing CMYK if you want, or disable the soft-proofing mode by choosing View > Proof Colors. Note that you can also always inspect the CMYK values by opening Photoshop’s Info panel and hovering your cursor over the image. However, those CMYK values are based on the CMYK setting in the Working Spaces section of the Edit > Color Settings dialog box. If you change the CMYK working space in that dialog box (in order to get more accurate CMYK values in the Info panel), be sure to remember to change it back after you’re done, or you may inadvertently mess up future images!
Low-tech tip: close your eyes
Before you make any settings in the Customize Proof Condition dialog box (View > Proof Setup > Custom), turn off the Preview option. Choose your settings, then hover your cursor over the OK button and close your eyes when you click OK. Wait for five seconds, and then open your eyes.
Yes, it sounds crazy, but here’s the reasoning: When you click OK, you’ll see the change from RGB to CMYK, and it will be ugly and you’ll be sad. But if you follow my advice, you’ll notice the difference, but it won’t be so dramatic. Avoid the temptation to do quick before-and-after comparisons, as they’re unrealistic and—if you think about it—not really helpful. The important thing is, how does it look in CMYK (not how it compares to the RGB version).
3. Save Your Images
Once you’re done editing and previewing your image in Photoshop, it’s time to save it—leaving it in RGB mode. In the Save As dialog box, make sure the Embed Color Profile option is turned on (it is by default).
One question I’m often asked is which file format to save Photoshop images in. The quick-n-dirty answer is: native Photoshop (PSD) for most images, or a high-quality JPEG when file size is an important issue. Or, if the image has vector artwork (like text layers) in it, then I recommend Photoshop PDF. (See InDesign Magazine issue 57 for a more detailed answer.)
4. Import into InDesign
When you place your image into your InDesign layout (see “InDesign 101: Placing Images” on page <?>), your RGB image appears on your page looking much like it did in Photoshop. InDesign automatically reads the RGB color profile that Photoshop embedded, which tells it what the RGB colors are supposed to look like—and how to display them properly on your page.
For the advanced color user (most people will never need this): By default, InDesign uses the Relative Colorimetric rendering intent. If your images are brightly colored business charts, you may want to use the Saturation intent instead. Or, if you’re dealing with a photographic image that has a wide spectrum of colors, you might find that the Perceptual rendering results in a better conversion to CMYK. In either case, you can control the rendering intent by selecting the image and choosing Object > Image Color Settings.
5. Soft Proof your Layout
One of the most common complaints I hear about using RGB images in InDesign is, “I need to show my client/boss how it will appear in CMYK.” Fortunately, InDesign has exactly the same kind of “soft proofing” feature we saw in Photoshop. To preview your document in CMYK, choose View > Proof Setup > Custom, and choose a target CMYK profile from the Device to Simulate pop-up menu.
As I mentioned earlier, I strongly suggest closing your eyes (or at least looking away from the screen) for a few seconds while you click OK and let your eyes adjust before looking back at your page. That said, I will admit that it’s kind of fun and educational to see both the RGB and CMYK versions of your document at the same time. You can do that by splitting your window, or using Window > Arrange > New Window to display a second window on your document. Then select either one of the windows, and turn on View > Proof Colors to see the CMYK version.
Remember that you can always see an accurate reading of CMYK values anywhere in your document in the Separations Preview panel (see InDesign Magazine issue 67). When you are soft proofing (when Proof Colors is enabled), the CMYK values that appear in the panel show the true CMYK values for objects and images.
6. Export PDF
The most important thing to remember in this process is that just because you place RGB images in InDesign doesn’t mean you’re going to send RGB images to your printer! InDesign can convert all the RGB images to CMYK for you, on the fly, when you export your print-ready PDF file. But before you do this, ask your printer what they want to receive. Many InDesign users who are disappointed with the color they’re getting when they send CMYK images discover that their printers are actually happy to receive PDF files with RGB images in them, and that this results in far better-quality color.
So, ask your printer if they’ll accept a PDF/X-3 or PDF/X-4 file. If so, that means they’ll handle the conversion to CMYK for you. InDesign can easily export a print PDF in those formats (just choose them from the Adobe PDF Preset pop-up menu in the Export Adobe PDF dialog box).
If they want a PDF/X-1a file, or they insist they want only CMYK in the PDF, that’s no problem. But don’t just leap to the Export button after choosing PDF/X-1a from the Adobe PDF Preset pop-up menu! Instead, take a moment to click the Output pane and choose which CMYK you’re targeting. This is critical.
First, make sure the Color Conversion pop-up menu is set to “Convert to Destination (Preserve Numbers).” Then choose the target CMYK from the Destination pop-up menu. Again, if your printer gave you a profile to use, you should choose it here. If your printer tells you to use a generic target, such as Coated GRACoL or Uncoated FOGRA29, then choose that. If your printer or output provider simply gives you an ink limit and no other instructions, you can build your own profile with a technique I wrote up at InDesignSecrets. In the worst-case scenario, where you truly have no idea how or where the document will be printed, or even on what paper stock, then leave it set to the defaults. (In North America, that means U.S. Web Coated SWOP, otherwise known as “middle of the road, mediocre color.”)
If you need to package and send your source files to the printer along with the PDF, those images will, of course, still be in RGB. If that scares your printer, you could convert these copies of your images to CMYK before sending them, but personally I’d rather find a different printer (one who lives in the 21st century).
RGB will always be the most flexible, robust, and high-quality format in which to store your images. While there are reasons to convert some images to CMYK before importing them into InDesign, these should be considered the exception, not the rule. Remember that converting to CMYK too soon is like jumping off a bridge: Don’t do it out of peer pressure, do it only after you understand your options and have made the decision for good reason. In the meantime, use a modern workflow and place RGB images in your documents. Your mom will be proud.