Gast
Hello,
Today I tried increasing the dilution of the Forte Negafort so as not to have to worry about extension factors (which Forte doesn’t specify) and to use it as a single-use developer.
The ready-to-use working solution (1 part Negafort and 3 parts water) was diluted again with 2 parts water, resulting in a 1+11 or 1/12 ratio in the developer.
According to pimalCalbeA49, I assumed double the time of the ‘standard batch’.
Test No. 1: old Jobo canister, 42 cc developer to 500 cc water, 10 mins 30 sec, then agitation every 30 sec for 5 sec, SVEMA FN 64 35mm film
The result was that the film at the edges – i.e. top and bottom, in the perforation area – was developed reasonably well, but in the centre it was hardly developed at all; this was very clear to see at the start of the film.
At first I thought it was an emulsion defect, albeit a rather strange one; after that I snapped another 15 shots onto a new roll of film (cropped) and developed it.
Attempt No. 2: AP tank, 33cc to 400cc of water, the rest as in Attempt 1
The result was almost the same, just developed slightly further into the centre of the frame.
What could be the cause of this?
An emulsion defect can be virtually ruled out, as I have already developed ten films from the same batch without noticing anything of the sort; to be on the safe side, I will develop the remaining film from the trimmed roll in stock solution, A49 or ID 11 to determine the cause.
However, the following occurred to me: was there perhaps too little developer, or might tilt development be advisable? Because somehow it seems to me that this is related to the perforation – the film was developed at the edges, but hardly at all in the centre.
Can you think of anything better? In any case, I wanted to describe the experience, as it has left me rather puzzled.
Best regards,
Roland
FrankJBeckmann
Hi,
I probably can’t really help you.
As for the uneven development, the only thing that comes to mind is that the perforation holes at the edge of the negative cause greater turbulence in the developer. From this, one might conclude that the developer is being used up too quickly in the centre of the negative. Perhaps you could try using a lower dilution to start with?
If that doesn’t work, you could have a look at the extension factors used by other developers and use these as a guide for your own experiments.
And if that doesn’t work, just change the developer.
Bye
Frank
Gast
Hello,
I agree with the previous speaker: underdevelopment in the centre during rotation development is a sign that the developer is being used up there more quickly than it is being replenished (through mixing). In my experience, ‘old-fashioned’, thicker-coated films are particularly susceptible to this. The problem shouldn’t occur in the tilt.
Best regards,
GeorgK
Gast
Thanks, that’s more or less what I thought. I’ll give Kipp developer another go, and if that doesn’t work either, I’ll either go back to using the standard developer or stop using this one altogether.
Roland
