About the HSV to CMYK Converter
Colours get chosen on screen and printed on paper, and the handover between those two worlds is this conversion. An HSV triple becomes an RGB triple by splitting the wheel into six sectors, and that triple becomes ink coverage by taking key as one minus the brightest channel and measuring the remaining three inks against what is left. Paste as many colours as you like, one on each line, and read back a cmyk() quadruple for each.
The result is a naive separation, not a colour managed one. Real print workflows apply an ICC profile that accounts for the paper, the ink set and the total area coverage limit, and the numbers they produce will differ, often noticeably in the dark tones where the naive formula asks for far more ink than a press can carry. Use these values to lay out a document and let the prepress stage refine them.
Expect a gamut squeeze as well. Anything with a value near 100 and a saturation near 100 in the cyan, blue or violet region is brighter than process inks can manage, and it will print flatter than it looks on your monitor. If the colour has to be exact across a print run, a spot ink is the answer and HSV to Pantone will suggest one. Coming back the other way is handled by CMYK to HSV.
How to use
- Paste HSV or HSB values, one colour per line.
- Press Convert to read the four ink percentages.
- Drop the quadruple into your layout file as a starting value.
- Refine it against your press profile before sending artwork.
Common questions
- Do I have to type the percent signs?
- No, saturation and value are read as percentages with or without the symbol.
- Why is the total ink coverage sometimes very high?
- The naive formula has no total area coverage limit, so dark saturated colours ask for more ink than a press will accept.
- Which colours suffer most in the conversion?
- Vivid cyans, blues and violets, because process inks cannot reach that part of the gamut.
- Can the hue be given in a form like 212deg?
- Yes, a trailing deg on the hue is accepted and ignored.