Cold Rinse Water a Problem?

[Scott Ridgeway www.Scott]

I'm using a Jobo fully automated processor with a built in water

heater. Today the heater stopped working. Fixing this will cost

more than the machine is worth. I can use an external heater

with a mixing valve for $200. My question is: Do I need to?

 

The incoming water measured 52 degree. It's used for

prewetting and rinsing for black and white film and fiber paper.

Will the cause problems? I can always extend rinse times as the

processor is automated. Can I process at below 68 degrees to

be closer to the rinse temp?

[frank.schifano]

I don't see too much of a problem with washing the film and paper after fixation. Sure, your wash times will extend some and if your processing temperatures are normally higher than the usual 68 deg. F you'll need to be careful of reticulation with film. I don't like the idea of using such cold water for pre-wetting film though. Using such cold water will chill the tank and your carefully tempered developing solution will lose a lot of heat when you pour it in. That can raise hell with your processing times.

 

Processing at lower than 68 deg. F can also cause some problems beyond extended development times if used with Metol/Hydroquinone or Phenidone/Hydroquinone developers. Below 60 deg. F, hydroquinone becomes all but inactive leaving you with Metol or Phenidone as the only active developing agent in your solution and both are very low contrast developing agents.

[chris_waller]

When I'm processing film I heat water in 2 litre jugs in the microwave. The temperature of my tap water varies. In winter it can be as low as 9 C (48 F). I have worked out a table of temperature vs minutes in the microwave to get it to 20 C. When I wash the film I use the Ilford Method and after each stage I add cold tap water to the main stock of water to lower its temperature in small steps. This way I don't shock the film with a sudden drop in temperature, but the final wash is probably at around 15 C. If you go below 15 C then I'd suggest you double the wash time.

[john_finch]

I agree with the comment about prewetting with cold water. It is asking for reticulation as the temperature jumps to your processing temp. Most developers are designed to work at around 20C. This is the optimum temperature for processing. The various amounts of chemical in the developer are balanced for the activity at that temperature and as we move further away from it, so the chemicals work at differing rates. As mentioned, some developing agents change quite dramatically or stop working at all at low temperatures. So just as Chris said, mix up water at 20C for all your processing. A Fish tank heater will do for the Jobo tank water, they are pretty accurate once set properly. From beginning to end the solutions and water rinses should be 20C plus or minus 2C (T-Max dev is used at 24C if I remember rightly but I never use it).

 

20C is easy to maintain, especially with the Ilford rinsing method which I also prefer. Good luck :) BTW, I am in Florida where the tap water is 82F at the moment! I have the opposite problem.... thank goodness for ice makers.

[garrylewis747]

How about a Watson?

 

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=86371&is=REG

[kin_lau]

Doesn't cold water cause the gelatin to shrink, and the grain clumps as a result? I believe there was a few threads around here that mentioned that.

[frank.schifano]

The reticulation problem occurs when you go from warm and wet to cold and wet. Going from dry and cool to wet and cool does not seem to be as great a problem.

[lex_jenkins]

There have been a couple of fairly recent threads discussing this issue.

 

Generally, the differences between the temperatures of the liquids that matters more than the temperature itself. Most films can be processed within a fairly wide range of temperatures. But all of the liquids should be as close as possible to the same temperature.

 

The tricky bit can be determining the best development times at the extreme ends of the temperature range.