A question about the C-41 process.

[ameerat42]

Hi All.
I'm wondering if someone can tell me whether the C-41 film developing processing is the same for all films. That is, for any film that uses the process, are all the times, temperatures, etc, the same.

I tried to seach on the net, and Wiki... stated,
"...The C-41 process is the same for all C-41 films, although different manufacturers' processing chemistries vary slightly..."

But that was as specific as it got. A couple of other sites were abpout the same.
Thanks, Am.

[peterking]

From memory the C41 is a standard that is clearly defined. However several of the process companies have modified it to suit their chemical concentrations and their own intended market.
Strictly speaking C41 is a process that any film thus marked can be processed.
The biggest thing I know of is if you use some of the cheaper labs then the chemicals may be more dilute, older, and therefore the result may not be the desired one.

[OzzieTraveller]

G'day Peter

As I understand it, process C41 was created by Kodak and (as the way things happen) soon became an international standard used by Kodak & non-kodak companies

I have not heard of differing companies 'tweaking' the chemistry for their own purposes - and in any case, it becomes neutralised when a town fotolab processes Kodak + Agfa + Fuji + ??? all at the same time in the same batch. Whether someone like Agfa or Fuji tweaked the chemistry in their 'home' labs is unknown ... it may have been done and as such, may have created slightly differing saturation (for example) than film processed at a local city lab

I do know that with home-processing of (both) C41 and E6 for slides, the home user could alter the end result by moving the colour-developer temperature up/down by a degree or two, thus creating some "quite different" results. The home-user could also "push" the ISO of a film by increasing the time the film remained in the developer as well

Dunno whether this helps ... hope so
Regards, Phil

[ameerat42]

Thanks, guys. Reason I asked was that I just shot two very old rolls of film, one 400ISO, the other 800. (The latter bought 7 yrs ago and sitting in my camera since.) Well, the latter was about 2 stops underexposed from the look of the negative. I just had this suspicion that the local store I took it to, though they send it away, might have developed both as "400ISO". But I guess that's not the case. Age may have done that. Nevertheless, I may never know what the story was.

I guess I'm just out by a few $s, as the shots were not critical except to see whether my lenses were OK. Well, they are, and I'm glad of that. Next comes the scanner for the better shots.

Keep an eye out. I'm posting a new thread about equipment to do C-41 processing at home.
Thanks, Am.