Dishwarmers

[ElliotC]

Hi

Does anyone know if a dishwarmer is adequate to maintain a constant temperature in a set of small dishes for developing B&W 5x4 film?

Many thanks
Elliot

[Louie Powell]

In my experience, processing B&W film does not require extremely precise temperature control. Also, the processing temperatures that are normally recommended (68 deg F, or 20 deg C) are close enough to typical room temperatures that they essentially maintain themselves.

My approach is to mix each of the chemicals to about 20 deg C, and also set up a tray of plain water at that same temperature to use as a presoak. From that point, unless the temperature in the darkroom is unusually cold or hot, the temperature of the chemicals doesn't drift to any significant degree.

[ElliotC]

Thanks Louie - I forgot to mention that my darkroom is in a cold attic. In winter the temperature can be very low. It doesnt take long for the temperature to drift by several degrees so getting consistent results is a concern.

[Peter De Smidt]

There are actually photographic hotplates. I have one from Kaiser that I really like. Unfortunately, I bought it as new old stock off Epay, and I haven't been able to find any more.

[Ash]

I've never worried for b&w.

In fact, I've used fairly cold tap water, straight out the tap without waiting for it to reach room temperature. Not seen a negative effect from this. The water was cool enough to be refreshing if I drank a glass (obviously without photo chems in it).

[Michael Kadillak]

It is imperative that one maintain temprature control throughout the development process or you really do not "own" the process and are not in control. The results you get are hit and miss particularly if you have a heat sink in the winter or heat adder in the summer. Both conditions are unacceptable to repeatable results. As the size of the film gets larger and the price for this product increases, this variable becomes absolutely critical.

Warmers that are not designed for the photographic process in general are not satisfactory for this application because they are not capable of holding 5 degrees let along less than one degree.

Best solution is to acquire a used Wing Lynch or another computerized water temp controlled and run a water bath for your process. They are not that expensive and are an investment to quality results.

If it is worth doing - then do it right. If it is not worth doing right, why not take up painting with watercolors.....

[Peter De Smidt]

Unless it's quite enclosed, a water bath will throw a lot of moisture into the darkroom.

[Michael Kadillak]

Unless it's quite enclosed, a water bath will throw a lot of moisture into the darkroom.

No biggie. Turn on the darkroom fan and break out the dessicant. Think positively of all of the dust that will not be capable of affixing itself to your negatives.

[Flexnib]

Not sure here I read it but someone was using a fishtank warmer to keep the water in the tray at a constant 70 degrees. Which in turn should keep the chemicals in the range you are looking for. Try this link-
http://www.fishtankshop.com/index.asp?PageAction=VIEWPROD&ProdID=10170
semms like a simple way to get what you need.
Arthur,nyc

[evan clarke]

Go to farmtek.com and see their pig warmer. I have used all these other things and this thing i twice better....EC

[Peter De Smidt]

If you go the fish tank heater route, I recommend the Won titanium heaters. They're not very expensive, they work well, and they're not as delicate as the glass heaters.

In winter, I use a Kaiser photographic hotplate on my print developer, and seedling mats on top of styrofoam under the rest of my printing solutions. The seedling mats give about a 6-8 degree rise in temp. This isn't ideal in my situation, but I bought the mats on super closeout.

[Steve Goldstein]

As an alternative to seeding mats, I use a heater designed for pet and animal use (someone earlier referred to "pig mats", we're probably talking about the same thing). The one I have is made by York, I think. It is not thermostatically controlled, but I use a small variac* with it and have experimentally determined the setting to keep the temperature in my developer tray close to 70F. It's plastic-covered but not completely sealed, so I'm careful about wiping up spills. I keep a small thermometer in the developer tray for monitoring and adjustment purposes. It has a rather long time constant, but I can make fine time adjustments based on the thermometer reading, so it's fine for printing.

For film I put the developer tray into a larger waterbath tray with one of the Won titanium aquarium heaters. In winter use a second Won heater in a deeper water-filled tub for preheating the chemicals, I plug it in a few hours ahead of time. This may be overkill, but I think I paid $15 each for the Won heaters.

*A variac is a kind of adjustable AC power transformer. In the US you can get them from Mouser or Digikey, among others, or with luck find a used one around as I did. If your heater is rated at 150W, then you'll need a 150W (or 150VA) variac. Variacs are often not isolated, so like any electrical gadget in a wet darkroom, you should have a GFI socket, or use an isolation transformer.

[Allen in Montreal]

Not sure here I read it but someone was using a fishtank warmer to keep the water in the tray at a constant 70 degrees. Which in turn should keep the chemicals in the range you are looking for. Try this link-
http://www.fishtankshop.com/index.asp?PageAction=VIEWPROD&ProdID=10170
semms like a simple way to get what you need.
Arthur,nyc

That is what I would recommend for an inexpensive but fairly accurate constant.
Get one rubber storage bin from the dept store and use that so the entire sink does not have to kept stable.

I use to do this with color with a unit called a Devtek as the heater and very small fish pump as the circulation, within the tub, the devtek would be over kill for b+w, but the concept is solid.