When it comes to using black color as background or the color of text, most designers will intuitively set the K value of CMYK to 100% with all the other three colors set to 0%.  While this K=100% only color does seem to be black on computer screens, it is actually a dark gray color when it is printed.

To set a true black color the CMYK values should be C=50%, M=40%, Y=40%, and K=100%.  With this setting, you can expect a very solid dark charcoal black as the black hole at the far end of the universe.