Why does inverting white produce black with fractions and not with pure values?

Question

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And why, when inverting from black, we do not get 100% pure white, but we get gray?

Answer 1

CMYK is always very much tied to a specific profile and a specific printing house. The recalculation is not based on some obvious formulas, but on the curves that are indicated in a specific profile. Tsmikov a million varieties and all different. If you change the CMYK profile in the PS / AI settings (SWOP, FOGRA, Euroscale, etc.), you will get different numbers.
Specifically, in the case of white, most likely, the limit on the total number of colors just works (in the color management settings, the Total Ink Limit parameter). If you add 70.48+67.98+63.16+73.46, you get 275% - quite a typical value (usually from 240 to 300, very rarely more). This restriction is made because if you print 400% (that is, CMYK 100/100/100/100), then the paper will become waterlogged and float.
Why didn't it just do CMYK 0/0/0/100? It's kind of pure black. Because it's a bitmap, not a solid fill! The raster prints black dots at intervals, and as a result, the field will look gray. The program is configured for a certain typographical profile, but the user apparently does not know which and why.
What happens in the second case - I don’t know for sure, but probably the color is inverted through PCS, that is, in CIE Lab or CIE XYZ.
In general, CMYK is such a thing ... it makes sense to use it only when you clearly understand what / how / why you are doing it. Where and on what it will then be printed, and so on. If there is no such understanding, then there is no point.

Answer 2

Because that's how Illustrator works.
And composite black, super black and other nuances are the basic knowledge of prepress.
You should go already and learn all the basics. Once during the last month on a completely non-core printing resource, you ask one question after another on this topic. A clear gap in knowledge that no Toaster can fill. Only training.
Well, or move to rudtp, printers live there and all questions will be, at least, profile ones)

Answer 3

Some kind of tin with color profiles and standards: www.eci.org/en/downloads It is
advised to use a profile: ISO Coated v2 300% (ECI)