Printing CMYK Grayscale

Morgan,

"Hi! I am trying to print something that uses grayscale colors,"

The best kind of greys rather depends on whether you are striving for neutral greys througout the artwork, or use greys along with other colours.

The best solution may also depend on which printer/printer service you are using, as Monika said..

Up to the saturation corresponding to 100K, you get actual grayscale by only using K, such as your 0,0,0,50, so that is safer for consistency; and it is also cheaper for more than one reason, one being the use of only one ink, another being that K is by far the most saturated colour..

But if you go beyond the saturation corresponding to 100 K and need CMY addition for that, it is better to have CMY additions for paler greys as well for consistency: it is more important to have a consistent appearance throughout than to have an accurate specific colour tone somewhere in the transition.

For neutral greys, I like the suggestion by Ton.

It is quite different if you use the greys with one or more other colours, and in those cases I would (normally) suggest greys/blacks akin to the (most important) other colour(s).

For coloured greys, you could use an adapted version of the suggestion by Ton, starting with an important colour represented in RGB, then (also) using HSB to keep the hue.

"my understanding is that rich black should be cmyk 60,40,40,100"

As I see it (literally), there is no right rich black for all purposes.

It will be difficult to find the correct CMYK mix to get a neutral grey. Your 30,40,40,50 mix is probably resulting in a brownish grey.

When you know the printing process/paper and have an ICC output profile for that process, you could use that to convert neutral RGB greys to CMYK.

Maybe you could show the design?

You have to watch that you get sufficient contrast into it.

And how will it be printed?