Print color basics
Rich black vs plain black: which to use and when
In print, “black” is not one thing. Plain black is a single ink. Rich black is black ink with some cyan, magenta or yellow underneath for a deeper tone. Each has a job: plain black for text and fine lines, rich black for large dark areas. Getting this right is one of the simplest ways to make a design print well.
Plain black: one ink
Plain black is printed with the black ink only. Because it is one ink on one printing plate, it cannot be out of register with itself: small letters stay sharp, thin lines stay clean, barcodes scan reliably. It also uses the least ink of any black.
The downside shows on large areas. Black ink alone over a big background looks slightly washed out, more like a very dark grey, and can show unevenness.
Rich black: black with support
Rich black adds cyan, magenta and/or yellow beneath the black. The extra inks fill in and deepen the tone, so a large dark area looks solid and deep. Some designers add more cyan for a cooler black, or more magenta and yellow for a warmer one.
The risk is ink. Every percentage adds up. Black at 100% with heavy cyan, magenta and yellow can get close to 400% total ink, which no printer wants on the paper. That is why print shops give a recommended rich black recipe or an ink limit.
When to use which
| Element | Use | Why |
|---|---|---|
| Body text, small headings, captions | Plain black | Sharp edges, no colored fringes |
| Thin lines, rules, icons | Plain black | No registration problems |
| Barcodes and QR codes | Plain black | Clean edges for scanners |
| Large backgrounds and big shapes | Rich black, within the ink limit | Deep, even tone |
| Very large display type | Either; rich black looks deeper | Big letters tolerate small misregistration |
What happens to black in a design-tool PDF
Design tools describe black in RGB. When the PDF is converted to CMYK, what you get depends on the exact color:
- Pure black (#000000) text and shapes. In our tests, CMYKflow converted them to black ink only (0/0/0/100). In our honey label example, the barcode bars and the small barcode digits are pure black and stay on the black plate only, with both Convert to CMYK and Safer for press.
- Near-black and dark grey (for example #121218 or #1E1E1E). These are different colors and convert to a mix of all four inks: a rich black. In the poster example, a near-black background (RGB 18, 18, 24) became about 80/71/51/87 after a plain conversion, 290% in total.
- Black inside photos is part of the image and is converted with the rest of the photo.
So, in your design tool: use pure black for text you want crisp, and expect dark backgrounds to become rich blacks.
Keeping rich black under control
A rich black that came from an RGB conversion can be heavier than a printer’s recipe. You do not have to edit numbers by hand. Safer for press replaces part of the cyan, magenta and yellow in dark areas with black ink, which moves a heavy four-color black toward a lighter, black-led mix. In the poster example the background went from about 80/71/51/87 (290%) to about 58/49/27/94 (228%) at Medium.
It also works on blacks that are already CMYK. In a test file, a CMYK rich black of 75/68/67/90 (300%) came back from Safer for press Medium as 48/43/43/97 (about 231%).
If a dark area looks less deep than you want after the reduction, turn on Deeper blacks, which keeps dark areas deep and full.
Checklist
- Small text, thin lines and barcodes: pure black in your design tool.
- Large dark areas: let them be rich black, but keep the total ink under control with Safer for press.
- Check the separations: text that should be black ink only must appear on the black plate only.
- Ask your printer for their rich black recipe or ink limit if you are unsure.
Frequently asked questions
What is a good rich black recipe?
Print shops have their own preferences, so ask yours. Common recipes add a moderate amount of cyan, magenta and yellow to 100% black and keep the total well below the printer’s ink limit. CMYKflow does not set a fixed recipe; Safer for press lowers the total of dark areas for you.
Why does my black text have colored edges in print?
Text made of several inks needs all of them to line up perfectly. When the press is slightly off, colored fringes appear around small letters. Black ink only avoids that. Use pure black (#000000) for small text in your design tool.
What does Deeper blacks do?
It is an option for Safer for press that keeps dark areas looking deep and full after the ink reduction. It works with Light, Medium and Strong.
Can I see whether my text is black ink only?
Yes. In CMYKflow’s separations view, text that is black ink only appears on the black plate and not on the cyan, magenta and yellow plates.