Tetenal E6 3 Bath First Developer color.

[dmtnkl]

I have been using Tetenal's E6 3 bath kit for a while now with very good results. I remember that a freshly diluted FD working solution (not the concentrate) had a yellowish color, and i was using this as a way to determine that the chemistry is in a good state.

Last time i prepared my working solution, it was completely clear with no color whatsoever. The 50ml concetrate came from a little bottle that was filled to the rim using a few glass marbles and was stored that way for a few months (maybe 3-4 months). Initially i was a bit alarmed but i went ahead and developed a roll of expired Sensia 100. Everything turned out fine... excellent colors, highlights and max density.

I am a bit puzzled how the FD working solution was completely clear and not yellowish, yet performed so well. Has anyone else encountered a similar situation? Does the color of a freshly prepared working solution really tell us something about how fresh it is or how well it will perform?

 

[Photomultiplier]

Normally it is the other way around. Fresh developer is almost colorless and with oxydation it turns more and more yellow.

A very faint yellowish tint was also what i often observed.

It is also hard for me to tell when the FD is too far oxydized, but i store them in seperate 50ml bottles, so i do not compromise the seal of the whole concentrate stock when i take one 50ml shot.
So if it is almost colorless, it should be as fine as it gets.

Side note:
I also repeatedly got white precipitate in CD Part 1 after some time, but never had problems with it. Now in my remaining bottles there is far more of the white stuff and i am reluctant to use it.

 

[dmtnkl]

So unoxidized FD is supposed to be colorless? I wasn't aware of this, quite the opposite actually.

I was getting an FD that was quite yellowish, even from freshly opened chemicals. I used the small Magic Box Kit, 1L kit and 2.5L kit. The results were fine each and every time.

Could it be that the kits had sat for too long on a store shelf? Below is a photo of the very first FD i prepared from a small Magic Box kit a few years ago. Since then, i grew accustomed to expect the FD to look like that and considered it normal.

 

[Photomultiplier]

I think it also depends on how long the sealed box sat on the shelf, yes

The FD turning more yellowish after mixing is something i also observed.

FD does not die abruptly but loses activity with increasing oxydation. There should also be buffers in the chemistry as far as i understand.
But i too do not have some kind of "chart" with activity-loss versus color tint

Your experience with the FD color is valuable as you know how far you can go at least with the FD color without compromising the results.

Do you work with nominal developing times from the handbook?

 

[dmtnkl]

Do you work with nominal developing times from the handbook?

Yes, i always use an fd time of 6:15 (even for velvia 50, we discussed this a lot in an older thread).

 

[Photomultiplier]

Then i would not worry too much. Nearly colorless developer was always something that made me happy. Maybe the buffering in the FD is good enough to inhibit detrimental effects even if
it turns yellow as in your case.

I don't think my FD was ever as yellow as yours, but i stored the concentrates in separate 50ml bottles which should give me the least possible oxydation.

Funny: The concentrates viewed in daylight show a different tint than in the evening with artifical light. Some light spectrum thing i suppose.

 

[dmtnkl]

I don't think my FD was ever as yellow as yours, but i stored the concentrates in separate 50ml bottles which should give me the least possible oxydation.

This is also how i store my concentrates, in small brown glass bottles, topped up with glass marbles to get completely filled.

The example photo i posted above was diluted straight from the 50ml FD bottle of a Magic Box kit. This was back when the product was first released, so theoretically it should have been very fresh.