Efke Kb25 And Tetenal Neofin Blue

bsm · 2004-08-03T10:45:25+00:00

Hallo, ich habe folgendes Problem mit der Entwicklung eines Efke KB25 und Tetenal Neofin Blau. Alle Ansätze mit 20°C und frisch. 7,5 Minuten 3Sek. Rhythmus...

bsm

Hello, I’m having the following problem with the development of an Efke KB25 with Tetenal Neofin Blaue. All baths at 20°C and freshly prepared. 7.5 minutes at 3-second intervals, all using distilled water, including the final 2 minutes of the final wash. In terms of density and contrast, the film is fine, but I have small, circular, lighter spots, about 1/4 mm in size, all over the film? Any idea what went wrong??? Thanks Boris

MirkoBoeddecker

Boris, Did you give the tank a good tap after filling it up? Sounds like air bubbles. Mirko

bsm

Boris, Did you give the tank a good tap after filling it? Sounds like air bubbles. Mirko

Hi! I’m not entirely sure, as I was working in 3-second intervals. But I reckon I must have slammed the can down on the table after filling it. It could well be the case, though. Regards Boris

Phillip

I had exactly the same problem with the combination of Efke 25 and Neofin Blaue. I always give the can a good shake when opening it and have never had this sort of problem before. I can’t think of any other explanation than air bubbles – perhaps Efke is more sensitive to this than other films, but that’s just my guess. Boiling the developing solution beforehand is supposed to help. Phillip

FoxTalbot

Yes, I also think that Efke film is faster than other films, especially since it has a new base material; that’s probably where the problem lies.

FoxTalbot

'More sensitive' refers to the air bubbles.

skahde

Another classic: gas bubbles caused by an acidic stop bath. If Neofin Blaue has only half as much to do with Beutler’s original formula as is often claimed, it still contains some carbonate as an alkali. If the emulsion saturated with developer is placed in a stop bath that is too concentrated, CO₂ bubbles form in the emulsion, which can leave holes in places. Try stopping with three water changes (that’s what I always do now; I only stop the paper) and see if that solves the problem. Best regards, Stefan