[4] (A safe and practical rule of thumb is that ink coverage should not exceed 240% on normal papers.

The difference is most apparent in backlit (also known as "translite") pieces, where rich black more thoroughly blocks the light from coming through.

In addition, excessive amounts of ink may not have a chance to fully dry before the printed result comes into contact with other pages.

The additional ink used to create rich black also results in higher printing costs.

[6] Care must be taken when using electronic design programs (e.g. when managing a CMYK document in Adobe Illustrator or Corel Draw) – "black" may or may not equal 100%K depending on the CMYK profile specified in the image's settings, and Photoshop will represent the various tones using RGB values close to black; in an RGB document, "black" always equals RGB value (0, 0, 0).