Colortone to CMYK: print values for named colors
A web palette built on CSS names eventually meets a print job: a poster, a sticker or a report cover. This colortone to CMYK converter turns a color name or code into ink percentages and adds tints, shades and tones in CMYK, so you have a set of print drafts that match your screen palette.
Example: steelblue in 4 steps
Tints (mixed with white):
0% cmyk(61.1%, 27.8%, 0%, 29.4%)
25% cmyk(41.7%, 19.1%, 0%, 22%)
50% cmyk(25.2%, 11.5%, 0%, 14.5%)
75% cmyk(11.4%, 5.1%, 0%, 7.5%)
100% cmyk(0%, 0%, 0%, 0%)
Shades (mixed with black):
0% cmyk(61.1%, 27.8%, 0%, 29.4%)
25% cmyk(60.7%, 27.4%, 0%, 47.1%)
50% cmyk(61.1%, 27.8%, 0%, 64.7%)
75% cmyk(60%, 26.7%, 0%, 82.4%)
100% cmyk(0%, 0%, 0%, 100%)The tones ramp ends at cmyk(0%, 0%, 0%, 49.8%), the ink equivalent of mid gray.
How the base value is calculated
Steelblue is rgb(70, 130, 180). The brightest channel is blue, so black is K = 1 − 180/255 = 29.4% and yellow is 0%. Cyan is 1 − 70/180 = 61.1% and magenta is 1 − 130/180 = 27.8%.
Patterns in the ramps
- Tints reduce every ink, black included, until only paper white remains. Because steelblue contains black, the tints are not a simple halving of the color inks.
- Shades hold cyan and magenta near 61% and 28% and raise black. The final step is K 100% on its own.
- Tones reduce cyan and magenta while nudging black up toward 49.8%.
Before you send it to print
These are simple-formula values without ICC color management. A commercial printer converts through a profile for the specific paper and press, which can shift the numbers, and screen-bright colors may print duller. Very light tints use small ink percentages that some presses reproduce unevenly, so check the lightest steps on a proof.
Also note that the conversion puts all neutral darkness into K. Prepress software may use a different black generation setting, giving other but visually similar recipes.
If you already have ink values, CMYK to Colortone builds ramps from them directly. For single colors, HEX to CMYK converts one code, and Colortone to HEX gives the matching screen palette.
Total ink and rich black
Printers limit the total area coverage, the sum of C, M, Y and K, because too much ink dries slowly and can smear. The limit depends on the paper and press; for coated stock it is often around 300 to 340%, and lower for uncoated paper. The simple formula used here always leaves one of cyan, magenta or yellow at 0%, so most results are well under that limit, but very dark saturated colors can still approach 300%. For steelblue the total is 61.1 + 27.8 + 0 + 29.4 = 118.3%.
The last shade step is plain K 100%. That is right for text, but large solid black areas printed with black ink alone can look slightly gray. Many print shops recommend a “rich black” that adds some cyan, magenta and yellow under the black; ask your printer for their preferred recipe rather than guessing.