quickbread answer — the how has to do with the printing more than with the taking. Film does matter, but paper matters more; is the print. The color negative is part of a process. That process of negative+positive has been broken most of this century. We don’t have a single research and manufacturing firm making aligned negatives and positives. No film made is made as perfect match to color paper. C-41 doesn’t match RA-4. We have industrial mismatch. Most, naïvely thinking that Color science has come to the rescue –all roads leading to the same place , when really all roads just lead to someplace .

So, the print is the resultant. And, we have only one maker, Fujifilm. Control of print values means understanding Crystal Archive’s renders.

Alter Chemistry is one pathway. Another is mask the color-negative.

Likely you, if new to darkroom, won’t understand the above sentence. So, the main, boldline is: do what you know, but learn more. Do more.

integral systems

means engineered system .. The color-negative -> color-positive system was aligned one with the other. The masks, the colored couplers, were specifically selected with the printing medium as an element of the engineering. This side of the bridge connects to that side. Correcting the negative for the printing stage — allow printing to be simple, done by small filter changes off base Red: for example: 40R, (40m & 40y). Balancing the enlarger-negative-paper chain should involve no more than 20 cc changes in a well considered product. Reminder: the red layer is the speed layer of the paper.

Assembly processes allowed greater variation. 

The media was designed for two different audiences: the naïve, novice, and the professional, the trained . Slides were meant to be evaluated in one way knowing that they would be used in a different way. Slides were meant to be projected ,therefore, they appear colder on an inspection table than when projected by a yellowish bulb onto a silvered screen.

In this era of film, the professional user, professional lab trained and experienced;  it’s such a rarity that I might be able to name two, but I couldn’t verify them with direct xperience . Labs are digital because the integrated process, the engineered process is digital. 

You won’t find anybody running three or five point AIM. nor will you find anyone who even knows how to have made a colored mask. These days , none of the chemistry is even available.

 

Color negatives from one product line do not fully match a different color print line . there was a time when labs knew this and they would segregate them, calling films from certain manufacturers foreign. The foreign designation meant that it did not match all colors fully on this paper printing line.. sometimes these results were just called subject failures; that was enough for the amateur answer. 

Matching grays is easy enough, it’s the edge colors where failure is obvious enough to cause rejects .

The current cliched  phrase is crossover ; this is the language of the channel speakers, who automatically think digital; not chemical, not emulsions.