Color fidelity
I would rather have both the color fidelity and the zero cost.
There is really no such thing as absolute color fidelity, but there is realistic and pleasing color fidelity. When I first started in color, I worked for a photographer who was a Master in the PPofA, a member of the Camera Craftsman (about as snooty an organization as you could find this side of the Atlantic Ocean, and a Fellow of the Royal Photographic Society, which was a degree of snootiness unobtainable outside England. We used 12 inch f/4.5 Pinkham Smith lens on a 9 x 12 cm Bermpohl one shot camera that split the image beam into three and sent them through a red, a green and a blue filter. The resulting color separation negatives were so superior to anything else then available, that I mostly avoided color when shooting outside the studio. It was pretty easy to get superior direct color separation negatives of that kind with a regular view camera and filters, on a rock solid tripod with an absolutely still subject, but not of anything else.
The printing method was trichrome carbon. That process produced excellent color prints, but it was to a degree limited to the size of your negative. Blowing up the negative produced lower color fidelity, and since the carbon process (sodium bichromate sensitiser) was very slow speed ... if I had to estimate, I'd rank it at about 0.001 Weston (if I'm not too forgetful, that would equal something close to the current ISO) ... you had to use a printing frame out in direct sunlight to expose it. And the sun being variable depending on clouds and time of day, that meant you needed three printing frames all placed next to each other and uncovered at the same time, and let "burn" for several minutes before covering again. We had some 16 x 20 printing frames for the purpose.
The owner gave up on Carbon because it was just too damned slow, and tried switching to Carbro, which used a black and white bromide print which brought into wet squeegeed contact with the Carbon paper, had a reaction with the bichromate sensitizer very similar to sunlight, so you could get big prints without going through all the sunshine rigamarole, but he gave up that method because it was not producing the same image and color quality. And because just about that time, Eastman Kodak came our with a process called "Washoff Relief", for which we made large film positives of the color separation negatives, bleached them in bichromate and dissolved the converted silver in sodium thiosulfate hypo, rinsed them in warm water to get rid of the unexposed gelatin emulsion, then soaked them in a dye solution, rinsed them off in a very week acetic acid holding bath, and then squeegeed them one by one onto a sheet of gelatin coated paper with a mordanting agent in the gelatin. The dye was attracted by the mordant, transferred over to the gelatin coating and you followed up with the other two dyed films.
The results were fantastic when we got it right. But getting it right wasn't easy. There was no electronic equipment involved. It was all eyeball estimates. We used a Kodak Gray Card that had been attached to a holder on the camera tripod so it was in the exact same light as the subject and therefore appeared in al three separation negatives. We also use a graduated gray card next to it. We had a "comparison densitometer", which was essentially a little scope with a graduated film strip in it so you could select a spot in the negative, and while that spot was visible in the eyepiece, feed the filmstrip through the other half of the viewing circle until it showed you a circular gray image with both sides exactly the same. Then you'd take you eye off the microscope and look at the number on the dial, and that was your "density".
The Eastman rep was there every day. This was apparently their real world laboratory. When it was finally a duplicatable process, Eastman renamed it as "Dye Transfer" and it became a standard for high quality color prints.
But proofs remained a problem, so we had a Leica mounted on the side of the camera that was patched into the cable release somehow so it shot a 35mm Kodachrome slide with every shot in the sitting.
There were two remarkable people working in that photo lab.
One was a Japanese named Kay Yamada. I remember one day at a coffee break, with the Eastman guy present, he told us about an idea he had to do this all electronically. He had a lot of it figured out, and it sounded like Science Fiction, but doable. And it was done within a few years. I have often wondered if Kay had a hand in its creation, or if that Eastman Kodak rep stole his idea.
The other was an old Mexican guy who was better than the densitometers of the day . He would hold up three color separation negatives side by side and view them against the overhead lamps, and tell somebody the exposure to make the three cym dye matrices. He was always closer than the comparison densitometer, so when the boss and the Eastman guy weren't around, the lab chief used to have him do the reading his own way.