Printing and Design Tips: March 2023, Issue #260

Color Problems in an Inkjet Book-Cover Proof

I’ve had this problem. It’s no fun. When you or your client gets a contract color proof and the color is not as you expect, it’s very upsetting.

This week I received an email from a print brokering client regarding her and her husband’s print book, a 184-page perfect bound book with French flaps. They are sticklers for quality, which I respect, and they were not happy with the purple color in the proof.

My clients had contacted the cover designer and had noted that the purple appeared “muddy.” Closer to brown than to purple. He had suggested adding cyan, reducing the magenta and yellow, and then requesting a new hard-copy proof from the printer.

Breaking This Down

First of all, I learned about 35 years ago when I was a book designer—when receiving a color cover proof that looked ugly—that this is actually a blessing. It could have been worse. My clients could have received the printed book covers and all of them might have looked ugly. The purpose of a proof is to avoid this. It’s a second chance. An investment, not an expense.

That said, my client had the printer’s inkjet proof in her possession, and the cover designer did not. He only had a monitor image on his computer. So my client sent him a photo, which looked just fine. That’s understandable. A photo taken with a cellphone camera is composed of red, green, and blue phosphors (like a desktop computer monitor). The image is created with light, whereas the proof image and the final book cover are produced with process colors (cyan, magenta, yellow, and black).

So the book cover designer had to respond to verbal information (from my clients, the publishers) and the RGB photo of the proof (RGB color also has a much wider gamut of distinct colors than CMYK process inks). Then the cover designer had to turn this information into a suggested remedy for the muddy purple.

I asked the designer about his physical working environment, noting that ambient light will also affect the appearance of the purple color on screen. Fortunately he works in the basement, where he can control the light (i.e., sunlight coming through the windows will not affect the appearance of the color on the monitor). That said, I’m not sure whether, and/or how, he calibrates his monitor, although it sounded like he does try to keep the color consistent and accurate, and in conformity with industry standards.

When I spoke to the cover designer over the phone, I also asked a few questions and shared some other facts about color reproduction:

1. The purple was both dark (in value, from light to dark) and neutral (less distinct than a pure color on the color wheel). That is, bright, saturated colors have not been contaminated by the addition of either black or the complement of the color. (For instance, blue is exactly opposite orange on the color wheel, and yellow is opposite purple. These pairs are complementary.) Two complementary colors become less saturated when mixed and tend toward brown, just as a color to which you add black becomes less saturated (or intense).

2. And in terms of value, it seems that lighter colors are more forgiving and darker colors are less forgiving. I’m not sure why, other than the threshold of visibility. If purple has a color cast, it’s darker and therefore more visible, whereas if yellow has a color cast it’s lighter (than purple, for instance) and therefore less visible.

3. Light affects the perception of color. Did the cover designer know in what kind of light (sunlight, tungsten, fluorescent) the publisher was viewing the contract proof?

4. Gender affects the perception of color. That is, women see color better than men (not sexist, just a fact). And anyone covering one eye and then the other will notice that even one person sees slightly different colors with each of her or his eyes.

5. In terms of proofing vs. actual book cover printing, the printing technologies used are different. The proof was produced via digital inkjet technology, and the final book cover will be produced via offset lithography. Granted, printers use CMYK inks for both inkjet printing and offset lithography, and commercial printers work very hard to match the behavior of their offset presses on their inkjet proofing devices. (This is why high quality inkjet proofs are considered to be of contract quality.)

What to Do?

First the book cover designer explained to the client all of the things I just explained to you. Then he suggested adding cyan, and reducing magenta and yellow. I believe he’s keeping the black at the same level to account for the overall darkness of the purple color. Making these process color changes will lean the purple toward a bluish rather than reddish cast.

The designer is making an educated assumption that the book publisher perceives the purple to be brownish (or muddy) because of the red (or magenta and yellow) component.

Second, the client (the publisher) will review a revised inkjet proof provided by the commercial printer. It will be another contract proof, which the printer will need to match on the offset lithographic press. And letting the printer know the process the cover designer went through (and even more importantly that the designer wants the final printed piece to be a more bluish purple and less reddish purple) will help.

The Takeaway

In short, it’s always prudent to be absolutely clear with the printer as to what your goals are. Always proof your color imagery, and if necessary change it and proof it again. It’s cheaper than a printing mishap. And always request a contract quality, hard-copy proof of any color work, because a PDF proof (for viewing on your monitor) will not accurately reflect the color range or gamut of offset lithography or digital printing.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]