Adox C41 Kit: Process at 38deg or 30deg.

[ChrisGalway]

Does anyone have experience of processing CN film (I'm about to process Kodak Gold) in the "3-bath" ADOX C41 kit at 30deg instead 38deg? Their instructions actually SAY "30deg for home use is recommended", but I know that the standard C41 temperature is 38deg (especially for the First Developer).

 

[pentaxuser]

Ah the old " colour crossover" question. I'd love to see a range of C41 negs developed at 30C and then printed under an enlarger and a set developed and likewise printed at 38 C to see if the differences are enough for me to say "not OK"

What always puzzles me is that there is a school of thought that says there will always be an issue at other than 38C and manufacturers of kits who claim otherwise or even recommend other temps without even as much as a hint that colour crossover might arise

pentaxuser

 

[ChrisGalway]

But surely Adox did proper colour sensitometry and compared the H&D curves? Goodness, I remember doing that 50+ years ago on my PhotoTech diploma course!

 

[koraks]

If you scan and digitally color-correct, you may not mind that there's a difference, but the closer you stick to official C41 process parameters, the closer the end result will be to what it's objectively supposed to be.

And yes, the negatives *will* be different. You just don't get the same negative with lower-temperature development. Whether or not the negative will be what you expect from it, is personal.

But surely Adox did proper colour sensitometry and compared the H&D curves?

You'd have to ask @ADOX Fotoimpex - but even if they did, this doesn't mean that the results were identical. It's still perfectly possible that the subjective assessment was that they found the results good enough.

 

[ChrisGalway]

I guess what threw me is that they actually say "30deg for home use is recommended". That seems weird if the standard is 38deg ... both require a temperature-controlled water-bath anyway so why recommend 30deg and not 38deg?

Of course I'll go with 38deg but I wondered if anyone had actually tried 30deg.

 

[koraks]

I suspect their reasoning is twofold:
* Small deviations in development time will affect the result less so if the development time is longer to begin with.
* A lower temperature means the developer is less energetic and this reduces the risk of uneven development especially due to adverse agitation or wetting patterns during the first 30-60 seconds of development.
The sacrifice is technical/objective correctness of the color balance of the negatives. But since this can usually be compensated for largely or entirely during printing or after scanning, I suppose this was accepted as a reasonable tradeoff.

Mind you, that's how I interpret the situation. I don't know for sure, and I sure don't necessarily agree.

 

[Spektrum]

In my humble opinion, ADOX includes this information because they believe that maintaining a temperature regime is easier at 30°C than at 38°C.

A few quotes from the ADOX C-TEC 41 DEVELOPING KIT user manual:

"Color development is not much more difficult than B&W. You can use ADOX C-TEC 41 between 24°C and 38°C - whichever temperature is the best for you to keep constant over the development time.
Lower temperatures are easier to control because they are similar to the ambient room temperatures, but the development time increases."

and second quote:
The standard processing temperature for C-41 is 38°C.
ADOX C-TEC 41 can be used at 38°C or 30°C.

(My note: inconsistency. First, they say it can be used between 24°C and 38°C, and then they say it can be used at 38°C or 30°C.)

third quote:
"The standard temperature for C-41 is 38°C.
30°C for home use is recommended, but with a rotary processor, 38°C can be maintained quite easily."


Personally, I wouldn't worry about the 30°C recommendation and would follow the standard process of 38°C.

 

[MattKing]

We may be seeing another example of the differing interpretations of the word "recommended" we have seen over the years.
"strongly suggested" is one example.
"acceptable" is another.
"not recommended" can mean "don't do it".
and "not recommended" can mean "not necessary" or "not worthwhile but it won't hurt"

 

[brbo]

Ah the old " colour crossover" question. I'd love to see a range of C41 negs developed at 30C and then printed under an enlarger and a set developed and likewise printed at 38 C to see if the differences are enough for me to say "not OK"

I've shown these a number of times here on Photrio:

What always puzzles me is that there is a school of thought that says there will always be an issue at other than 38C and manufacturers of kits who claim otherwise or even recommend other temps without even as much as a hint that colour crossover might arise

Why does that puzzle you? There are many things that are produced to "as good as possible" or "as long as it works" standards.

 

[pentaxuser]

brbo,thanks for your#9 Yes I have seen your shots before. I believe I first saw them when David Lyga started such a discussion about what he did. I had another good look at them but like the first time I see no difference that makes your 30C inferior to your 38C

Maybe it is my eyes that are at fault. All that matters is what Chris sees. If he sees a difference that makes 30C a "no-no" for him then that's fine

As far as your point about why I am puzzled about no mention by Adox as to the problem of the likes of colour crossover at 30C, I refer to the final few words of my quoted sentence namely "without even as much of a hint of colour crossover "

I'd have expected a company like Adox to at least make some mention of it. Here's an analogy

You and I make rival washing powders, both of which wash clothes equally well at 38C but I know that my powder does not wash as well at 30C or certainly not all the time However to make my powder easier to use by consumers and possibly more attractive I advertise it as being capable of doíng its job at 30C when I know this will not produce the same quality wash, at least not in all circumstances but I choose not to even hint that this might be the case when I know it to be the case

Is that demonstrating 100% honesty to the customer ?

Of course we may simply be looking at what we should expect from the maker of a product from two different standards of behaviour? In either case let's agree to disagree

Thanks

pentaxuser

 

[Spektrum]

I usually read the manufacturer's instructions carefully and try to follow their recommendations exactly.
However, in the case of this C-41 kit from Adox, I don't recommend following everything in the manual.

First of all, they recommend rinsing for 30 seconds with warm water after developing.
Rinsing the film with warm water after the developer doesn't stop the development process, and not only the temperature but also the time is crucial here.
Perhaps with an 8-minute development time at 30 degrees Celsius, the extra 30 seconds of rinsing won't affect the development as much, but at the standard temperature of 38 degrees Celsius, overdevelopment will occur.

There was already a thread on this forum started by someone who used this kit from Adox.
He had problems with colors etc.. After using the STOP bath, these problems disappeared.

I also highly recommend converting the BLIX from this kit to a separate BLEACH.

As @Rudeofus mentioned here in his article:

Converting C-41/E-6 BLIX into Separate Bleach and Fixer

1 Introduction Many C-41 and E-6 kits come with BLIXes to remove silver. These BLIXes sometimes don't work all that well, and some of the BLIX concentrates have limited shelf life. The main purpose of this document is to provide a brief...

www.photrio.com

According to Adox, BLIX is only sufficient for 16 films, and they don't recommend overclocking.
After a fairly simple conversion to BLEACH, this bath is enough to bleach about 50 negatives and can be stored for up to a year.

ADOX C-TEC 41 is a chemically perfect clone of the former Tetenal Colortec C-41 Kit.