The issue of Rich Black Settings in Large Format Printing comes up a lot. This is probably the most common design issue that I encounter. If you want a nice deep bold black, you will want to use what is called a “Rich Black”. This means that the black is actually made up of multiple colors rather than just black pigment in order to obtain a really nice dark black. The reason this comes up a lot is because Adobe Illustrator’s default black setting is commonly set to ‘true’ black with no other colors. Let’s compare the difference of “True Black” when just using the black pigment and “Rich Black” using the black pigment along with other colors:
| Rich Black (the one we want) | True Black: (sometimes Illustrator’s default black) |
| C: 75% M: 68% Y: 67% K: 90% | C: 0% M: 0% Y: 0% K: 100% |
See what I mean?
If you recall hearing about CMYK printing or a 4-Color Print Process, this means that a printer (not much unlike your home desktop inkjet printer) uses 4 different ink pigments to achieve all the colors needed to create your banner and all other print jobs. Those 4 pigments are
C = Cyan
M = Magenta
Y = Yellow
K = Black
When you use Illustrator’s default black setting of 100% black and no other color values, it looks really good on your computer screen but can print out entirely different. When a Large Format Printer only uses one pigment it actually can look pretty dull. In the case of black pigment, it kind of looks like an ugly dark gray.
When you use Rich Black Settings, like the one listed above, it uses a combination of colors to achieve your black color. The result is a nice deep, bold black that you would come to expect for text, backgrounds, or any other design element.
Note: There are more than one Rich Black Settings you can use so please check with your printer. I have always used the one shown above with good results, but again check with your printer to avoid problems like Over-saturation.
Here is a brief video tutorial which shows the difference between these 2 black settings in Adobe Illustrator and Adobe Photoshop:
Hopefully this helps explain the difference between these two settings.