Shifts in professing results

[Filip Plesha]

It has been a while since I have posted a question on these boards, just been listening and commenting, but I a currious about something..

 

In still photography there are a lot of alternatives when it comes to processing.

For example, process C-41 is almost a myth in consumer and even pro processing. In reality, there are all kinds of variations used, quicker and cheaper and they are all shorter than the theorethical C-41. Kodak makes it's own two variations, Agfa makes its own processes that are compatible with C-41 etc.

And even though people say the results are identical, tests show that there are all kinds of variations in contrast, granularity,speed etc. Very subtle but still there.

 

My questions would be:

1.Are there any variations of the ECN-2 process?

2.Are there any manufacturers of ECN-2 chemicals other than Kodak?

3.If the answer to 1. and 2. is yes, are there any visible differences in results?

4.Do different motion picture labs give different processing results?

and

5. does Kodak has its own motion picture processing lab?

[Dirk DeJonghe]

1. there are several kinds of bleach bath formulations, but the basic developer is the same for everybody.

 

2.. Until recently Kodak did not make prepared kits for mixing chemicals, everything was mixed from bulk chemicals bought on the open market.

 

3. Besides the chemistry, mechanical factors also play an important role (turbulation, filtration, temperature, time). If there is a difference between labs it's mainly because they allow chemistry to drift out of specs.

 

4.Good labs should be very close to another in output.

 

5. Kodak owns a few labs (In Romania I believe). Generally they don't want to be in this business.

[Dominic Case]

Dirk gves good answers to all 5 questions.

 

Also,

 

1. ECN2 is the standard process for all colour negative stocks - from Kodak and also from Fuji. There are indeed different bleach formulations, and slight differences in fixers: but developer is developer.

 

2. Kodak sources its chemicals from the open market (even dedicated things like the colour developer agent CD3): many labs mix their own chemicals - to Kodak specs - using raw chemicals also sourced from the open market. Good labs normally analyse the resultant mixes to check that everything is in order: and analyse the working solutions regularly too.

 

3. Not between good labs, all of which follow Kodak specs quite closely and participate in Kodak programs to monitor their results against Kodak standards.

Regular sensitometric testing ensures that the final results are consistent and compatible. Labs might vary slightly in detail on any given day, if - for example - they adjust the pH of a solution slightly to compensate for some other variation: or increase the development time by a couple of seconds to offset a slight chemical drift. Tolerances are tight though - to within 0.1 degrees, and about 2 seconds.

 

4. The overriding aim is for the look of the negative to remain consistent over a long run - and to be the same as the reference standard. Some DPs occasionally run a test through several labs to pick one: the differences, if any, tend to be in the colour of the work print or the transfer, (or the efficiency of the service) rather than in the negative.

 

5. Kodak have a couple of labs around the world. Most noticeably they own Laser Pacific in LA.

 

If John Pytlak is around, he might mention the Kodak Image Care program - which is a quality assurance program that exists to allay any fears of variability in labs.