Little information is available even from the web, about 'proper process calibration' that Kodak or Fuji might want labs to maintain for their processing equipment.
Can you provide us with an explanation geared for the layman, about how often/when such calibration should be done, either in terms of time intervals or vulume of photos processed or whatever threshhold?
And then also comment about throughput (let's say 1995 vs. now) and how that increases the need to calibrate or the challenge of maintaining calibration?
I can speak about E6 for example , the best Refrema's in the world needed volume to keep the plots in line, PE jump in to explain E6 plot theory. The one lab I worked at that had a incredible
E6 line was Colourgenics in Toronto, It was for years was in Fuji's top ten for plot control ... Basically the machine would run calibration at 6 am , plots checked and adjusted if needed , then every two hours
for the rest of the day a control strip would be run to keep the line solid.
This may be overkill but some of these small dedicated E6 labs were turning over incredible amounts of film 7 days a week and the plots needed to be consistent.... Remember Grey Backgrounds will show any drift and we did not have the Photoshop tools to fix any cross overs.
Today vs 1995 - well I own a Durst Lambda 76 which in the last 25 years has been a powerhouse for creating prints. Today I no longer make C prints with it as I feel inkjet prints are better in many ways, I use it only for Black and White silver prints and Black and White silver negative .
Toronto Image Works still does C print and is in Toronto as my lab is, I still feel TIW is as good as the old days because Ed Burtynsky owns it , uses it and is a lab tech through and through. Most of the lesser labs in Toronto have fallen through the cracks, and the good E6 labs are all gone due to lack of film.
Today the ink machines are extremely stable and require one good Profile to keep in Balance.. The spectrometer is the key and a good tech making the profile.
Today also I am making alternative prints that are much more demanding than any prints I have made in the past, keeping control of the gum process in colour is quite daunting and once Sean finishes
the new site design I can talk freely about the new real wave of photographic printmaking.
hope this helps
Bob