Pure Black vs Rich Black

In printing, unexpected details can often arise, such as when designing a file in CDR where the intended color is black, but the printed color appears less black. In the following explanation, I will discuss the differences between Pure Black and Rich Black, as well as how to achieve pure black during the printing process by setting CMYK values.

What is Pure Black?

To understand what Pure Black is, we must first explain CMYK. In modern printing machines, four ink colors are used: cyan (C), magenta (M), yellow (Y), and black (K). Any color is produced by mixing these four ink colors.

The four ink colors are combined in percentages.

For example, if I tell you the CMYK values of a color are: C-100 M-50 Y-0 K-0, it means that on the printing plate, the corresponding point is fully coated with cyan (C), half-coated with magenta (M), and not coated with yellow (Y) or black (K). Thus, this color can also be described as 100% cyan plus 50% magenta.

On the other hand, Pure Black  has the CMYK values: C-0 M-0 Y-0 K-100. In other words, it is 100% black.

100% black is referred to as “pure black” or “100% Pure Black” in English. How black is it really? Actually, it is not very black, and it may not even reach the lowest end of the color picker.

What is Rich Black?

So, what about Rich Black? Does it involve using cyan (C), magenta (M), yellow (Y), and black (K) inks together? Yes, that’s correct. Due to Pure Black not being “black” enough, the idea of “mixing the four inks to obtain a darker ink” came about.

Compared to Pure Black, Rich Black is a broad concept. As long as the color appears close to black to the naked eye and uses all four ink colors, it can be defined as Rich Black. C-60 M-40 Y-40 K-100 is Rich Black, C-100 M-100 Y-100 K-100 is Rich Black, and C-80 M-80 Y-80 K-90 is also Rich Black. In simple terms, Rich Black appears darker than Pure Black.

Most printing factories often set the color values to C:40 M:30 Y:20 K:100 when printing pure black. This setting effectively avoids excessive ink volume, which could cause ink smudging on the back of the printed material, and allows the ink to dry quickly. Excessive ink volume leads to slower drying, which can affect subsequent processes.