AgI is insoluble in water so it along with other silver halides will stay in the gelatin.
AgI is insoluble in water so it along with other silver halides will stay in the gelatin.Do we have any polite comments about prewetting and 2-baths? My thought is to reduce the accumulation of dyes and iodides in the first bath.
Naturally the first bath would have to be extended abd vigourous.
The KI should be washed out along with the nitrates during the washing of the emulsion prior to coating. Correct??mshchem, we agree. But what about the KI and whatever light sensitivity curve altering chems?
To be specific my interest is the degrading of Dignan's 2-bath C-41 developer which is almost universally extolled then, a few films later, deemed not so good after all.
Would a prewash help, maybe?
I point out that most of what is in the last B&W sticky covers the ground here. PE, on questioning, said he used a prewash for everything.
Three minutes of continuous agitation for me.
As part of a consistent, repeatable process which provides results that satisfy my needs.
I always work at room temperature, including using room temperature pre-rinse.
I also think the colours are pretty.
I have never seen a commercial film processing machine that pre-wets the film. In a commercial lab, time is money, so why pre-wet when it is not necessary.
Maybe where a lab uses a non-automated process, rotary tank, small tank etc, they may see the need for a pre-wet, but in all my years processing commercially and talking and visiting other labs, big and small, professional and amateur, I never saw a pre-wet/pre-wash used.
As an analogy, it remind me of the argument about cooking pasta. One says to use a big pot with plenty of water. The other says that a drop of oil into the water in the pot will stop the pasta from sticking.
Discuss.................
In the Colenta, pre-wetting was mandatory for B&W REVERSAL processing (AGFA SCALA)!
I would hazard a guess that most commercial processers now are roller processors.One may not forget that in commercial (professional-) labs the processing is done with nitrogen gas agitation, which is absolutely completely different than hand- or rotation agitation.
I have to say I cannot see why there is KI and KNO3 applied before the emulsion, only to wash it off before that step in manufacture. IDNK how or why it would be done. Sorry.The KI should be washed out along with the nitrates during the washing of the emulsion prior to coating. Correct??
I would hazard a guess that most commercial processers now are roller processors.
A few dip and dunk lines remain, and they should be supported, but they require high volumes to make sense.
BTW the film 'spirals' in my Colenta (home-) developing machine had a diameter of about 30cm, a 120 roll film could be wrapped around, emulsion outside, in ONE turn (not overlapping), that's why they were called 'baskets' instead of spiral's! The agitation was alternating rotation and I could process 10 120 roll films in one run and 2,7 liters where needed per bath.
Are you still using the Colenta?
I would hazard a guess that most commercial processers now are roller processors.
A few dip and dunk lines remain, and they should be supported, but they require high volumes to make sense.
my Colenta (home-) developing machine had a diameter of about 30cm, a 120 roll film could be wrapped around, emulsion outside, in ONE turn (not overlapping),
No, as a matter of fact, I am thinking of selling this Rolls-Royce of the small professional developing machines.
I would hazard a guess that most commercial processers now are roller processors.
A few dip and dunk lines remain, and they should be supported, but they require high volumes to make sense.
Is there any information on these machines online?
Very nice outfit! Perfect.One may not forget that in commercial (professional-) labs the processing is done with nitrogen gas agitation, which is absolutely completely different than hand- or rotation agitation. These gas bursts are chasing air bulbs and, if I am not mistaking this gas is warmed up at processing temperature (REFREMA machine).
Also in these DIP&DUNK machines, the film is HANGING vertically with a wight at the end, so the liquids are freely moving around the filmstrips, no spirals where the film is wrapped around with such a small diameter according the tank.
Never compare professional lab processing with DIY home developing.
BTW the film 'spirals' in my Colenta (home-) developing machine had a diameter of about 30cm, a 120 roll film could be wrapped around, emulsion outside, in ONE turn (not overlapping), that's why they were called 'baskets' instead of spiral's! The agitation was alternating rotation and I could process 10 120 roll films in one run and 2,7 liters where needed per bath.
In the Colenta, pre-wetting was mandatory for B&W REVERSAL processing (AGFA SCALA)!
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