Black or rich black

(To Do: Afbeeldingen, links naar en van  en tussenkopjes toevoegen)

In print, 100% black becomes even darker when other colors are mixed in. Graphic designers have known this for years. Color in print is typically created by mixing Cyan, Magenta, Yellow and blacK (CYMK) ink. This works best when the printer ink is partially transparant, thus making the underlying ink shine through, optically mixing the light that is reflected by the paper underneath it.

Black is not a color, but the opposite: The absence of color. A surface that is covered with black ink absorbs most of the light that falls on it, but not all. Some light will still reflect because there is no such thing as 100% black pigment. By adding more, halftransparant layers of ink that block specific other colors, even less light will be reflected. This black mix is usually referred to as rich black in Adobe applications preferences.

Transparant lacquer and even matte lacquer can also deepen black, as well as colors.

Rich black also works for laser printers and inkjet printers.

While making prints with my Brother MFC, I noticed black text looks different on some prints. It comes in two variations of black. One is sharper, but less black even though the text 100% RGB black in both digital documents. Still, the other text is printed slightly fuzzier, but deeper black.

I have often noticed this and tried to find an explanation for it. Obviously it had to be something in the software since both black or rich black prints came out of the same printer.

My first hypothesis was, that this was caused by the black or rich black preferences in Adobe Illustrator. Then I though it had to do with the color system the document was set to: RGB or CMYK. However, these turned out to be a false assumptions. I feel I never got to the bottom of it, but I suspect the printer’s RIP handles the document data as if it’s in RGB colors, even if it’s really set to CMYK and even though the printer uses CMYK ink to print it.

Now, years later I think I have found the cause. I had already noticed PDFs from others, like invoices that I got per email, would print in slightly duller black, but resulting in a bit sharper text than my own PDFs. It was hard to see, even with a magnifying glass, but my home-made black texts had minuscule colored spots around the edges.

This is the result of choosing different color management options. The Illustrator documents I printed had color management information with them. This results in rich black printed black text. The PDFs from others had no color management options specified. In that case, the printer uses it’s own color management. In practice, this means that 100% black is printed in 100% blacK – no more, no less.

I suspected the printer companies to have their printers default to rich black, since they seem eager to sell as much ink cartridges as possible, but apparently I was wrong. So, there you have it. Print black text with color management off, if you want to safe ink.