Suppose there are two colors defined in CMYK:
color1 = 30, 40, 50, 60
color2 = 50, 60, 70, 80
If they were to be printed what values would the resulting color have?
color_new = min(cyan1 + cyan2, 100), min(magenta1 + magenta2, 100), min(yellow1 + yellow2, 100), min(black1 + black2, 100)?
Suppose there is a color defined in CMYK: color = 40, 30, 30, 100 It is possible to print a color at partial intensity, i.e. as a tint. What values would have a 50% tint of that color?
color_new = cyan / 2, magenta / 2, yellow / 2, black / 2?
I'm asking this to better understand the "tintTransform" function in PDF Reference 1.7, 4.5.5 Special Color Spaces, DeviceN Color Spaces
Update:
To better clarify: I'm not entirely concerned with human perception or how the CMYK dyies react to the paper. If someone specifies 90% tint which, when printed, looks like full intensity colorant, that's ok.
In other words, if I asking how to compute 50% of cmyk(40, 30, 30, 100) I'm asking how to compute the new values, regardless of whether the result looks half-dark or not.
Update 2:
I'm confused now. I checked this in InDesign and Acrobat. For example Pantone 3005 has CMYK 100, 34, 0, 2, and its 25% tint has CMYK 25, 8.5, 0, 0.5.
Does it mean I can "monkey around in a linear way"?
If you're just doing tints of colours then a straight multiplication will be fine - this ensures that the inks will all be in the same ratios.
You can see this by bringing up the Colors panel in InDesign, and holding down shift and dragging one of the colour sliders. The other sliders will move proportionally.
Adding two colours has the same effect as overprinting (where one colour is printed directly over another colour). So if 100% magenta and 100% cyan were printed, and then 100% black were printed on top, the result would be exactly the same as 100% magenta, 100% cyan and 100% black.