Color wash time vs B&W wash time

[synj00]

Been doing my own DIY color, pain in the butt actually to get and keep the chems at 102F. But this got me thinking: if a 3 minute wash time is good enough for color film why is a waaaaaay longer wash time recommended for b&w when using even less chemicals than color. Emulsion is emulsion?? :confused:

 

[DanielStone]

are you referring to fiber or rc papers? If its RC, then you don't have to wash for hours, like some people do. For RC I generally do about 15min for a final print, 5min for a work print. for fiber, I wash for 2-3hrs. I just like to make sure that ALL the residual fixer, and hypo, selenium or other toners are COMPLETELY out of the print.

and being that fiber is FIBERS, not a coated piece of plastic( like rc and color(rc paper too) prints are. Even with color prints, I like to re-wash them for 5-10min after they've gone through the processor. Water is at 70F.

-Dan

 

[synj00]

Oops should have mentioned that I'm just talking about film, not paper. Fuji recommends washing for 20-30 minutes. I usually just use the Ilford wash method and havent had any issues.

Just wondering why color film only needs 3 minutes wash to get all the blix out but fuji recommends 30 mins?

 

[fschifano]

Yeah, there does seem to be some kind of disconnect there. I think that 30 minute wash for B&W film probably has it's origins in the time when highly acidic hardening fixers were the norm. Today's rapid fixers are generally much less acidic and often don't contain hardeners. C-41 fixer is almost neutral (ph 6.5 or so at working strength) and has no hardener. You can use it, but not blix, for B&W films and papers too.

 

[Dave Pritchard]

C41 film will not last as long as black & white. One can be archival, the other is not. The C41 process is also designed for mini-lab processing. The mini-labs do not want excessive wash times and do not desire to have a large amount of wash water to dispose of.

 

[fschifano]

No argument there, but I still question the need for a 30 minute wash time for B&W films. The support absorbs no water, only the emulsion does and that is very thin. I use 10 minutes and at the end of that time, my negatives are very clean of residual fixer. An important consideration though is that the wash water is at or very close to processing temperature. Very cold water can double or triple that time to achieve the same end.

 

[synj00]

Mmmm cold water.. I hadnt thought of that one.

 

[Dave Pritchard]

You may be right. Most of the concern about archival stability that I've heard is really about prints, not film.