About the CMYK to Colortone Converter
A CMYK quadruple states how much cyan, magenta, yellow and black ink lands on the sheet. That is exactly what a press needs and exactly what a conversation cannot use. A brief asking for terracotta gets understood; a brief asking for 0, 49, 60, 11 gets ignored. This converter expands each quadruple to sRGB with the standard subtractive formula and then reports the nearest entry from a library of named tones including Saffron, Cerulean, Gunmetal and Sage.
The comparison runs in CIE Lab so the winning name is the one a person would also pick as closest, and the delta E beside it says how far apart the two really are. Bear in mind that the trip from ink to screen here is a plain formula with no ICC profile behind it. Rich blacks, heavy coverage and uncoated stock all shift the printed result away from what the maths predicts, so treat the name as a description of the artwork on your monitor rather than a promise about the press sheet.
Write each colour as cmyk(0%, 49%, 60%, 11%) or as four bare numbers separated by commas or spaces, one colour per line, with every ink value between 0 and 100. Anything outside that range is refused rather than clamped. When you need a reference a printer can actually mix, CMYK to Pantone is the right stop, and Colortone to CMYK runs this conversion in reverse.
How to use
- Paste CMYK values, one colour per line, with or without the cmyk() wrapper.
- Press Match to see the ink colour beside its nearest named tone.
- Use the delta E number to decide whether the name is close enough to quote.
- Copy the names into your artwork notes or client brief.
Common questions
- Are the percent signs required on each ink?
- No, the four numbers are read as percentages whether or not you type the symbol.
- Why does a heavy ink mix return a lighter sounding tone?
- The screen conversion ignores paper stock and dot gain, so a mix that prints dark can land on a brighter neighbour.
- Can I run a whole artwork palette through at once?
- Yes, put each quadruple on its own line and the results come back in the same order.
- Is this accurate enough for a press proof?
- No, it is a naming aid only, because no ICC profile is applied to the conversion.