Updated: Apr 29, 2019
Have you ever looked at your printed piece and wished that the black was darker and richer? When designing a print project there are several things to consider about whether to print blacks as 4-color black, or just 100% black only.
If you're printing on an offset press, any large black objects and/or text will look deeper when using rich black. In general, I’m talking about text that's 36 pt or larger, or any fill that is about the size of a letter set at 36 pt or larger.
The standard formula that we’ve proven to yield the best results are 50% Cyan, 40% Magenta, 30% Yellow, and 100% Black. Sometimes people will use the default Photoshop black (75 C, 68 M, 67 Y, and 90 K). Since the black is not 100%, the edges of your objects will have rough edges due to screening. This is true of any screened objects or illustrations.
Small objects and standard sized type should be left as black only. Presses have great color registration, but none are perfect. Thin stock, sheet stretch and varying environmental conditions can exacerbate registration problems. Small type or objects can show a colored halo around the letters due to less than perfect registration.
If you are printing on a digital press, the best Idea is to find out which technology the press uses. Some digital presses print 100% black darker than a 4-color combination and some look better as a rich black.
In flexographic printing, the black ink is typically more opaque, and laid down with a thicker film. Because of this, using black alone is the best option.