Processing: What About Water?

[peter brooks]

I used to temper stop and fix in a water-filled medium sized plastic storage box with an aquarium heater (rubber suckers adhere to side) and thermometer, holes cut in the lid and 1" polystyrene insulation cut to fit the outside bottom and sides. Realised after a while that this was overkill.

Current darkroom has the bench over the central heating boiler - an old one, not very efficient so gives off quite a bit of heat. By moving the chemicals to different locations I can vary the heat gain. I always move a bottle of distilled water around with the stop and fix (all in acrylic type straight sided 1 litre wide necked drinking bottles), and use a thermometer to take the temperature from that. So if you have a source of gentle heat, get to know it, with experience you can gauge how long it will take to heat the stuff up and just plan ahead.

I think the dev temperature is more important than that of the stop and fix (within reason).

No water supply in the darkroom so for dev and main rinse water I mix water from a boiled kettle and tap water in a large jug, adjust using a thermometer and decant into thermos flasks. We are on a spring, so the supply is probably full of all sorts of bits and pieces (it does have at least UV treatment before it gets to us).

I used to get a lot of debris on negs, I sought advice from the one remaining analogue photographer at a local club and he suggested always doing the final rinse with distilled water. I do that now (actually I use it for the final rinse and the photoflo dunk) and it makes a world of difference. Hence the bottle of distilled water ready at the ballpark temperature.

Print trays I boost temperature if required with a vivarium heat mat. Works a treat, nice and gentle but not too sloooow.

[Two23]

Sounds like trying to filter tap water isn't the way to go.


Kent in SD

[Doremus Scudder]

It's easiest to just process at ambient temperature if it is within processing parameters. Store your water and chemical stock solutions at room temperature. Then just mix what you need and measure the temperature and make any development time adjustments needed if your temperature is not exactly 68°F/20°C. For wash water, get a thermometer well for your faucet and adjust the temperature to ambient before washing (or, get a more expensive, but more convenient temperature control valve or even an electronic water temperature control mixer).

If the tap water is routinely too warm, as it often is in the South and Southwest, then you'll need a different approach. You need to bring your chemicals up to the temperature of the tap water (assuming it's not too hot for processing - up to 25°C is fine). Not too difficult with a water bath. Use hot water to get the solutions close and then a tempering bath fed by the "cold" tap water to hold things at temperature during processing.

Processing in the cold is more problematic, since developers with hydroquinone lose activity at colder temps. If possible heat the area and get everything up to ambient temperature. Alternately, water baths and tempering baths get things warmed up and held at processing temperature.

If you process in the summer, and don't have air conditioning, you can still easily mix things at 20°C and just shorten development time for the small temperature increase in all solutions that occurs during development. In my Vienna "darkroom," it was often 30°C (86°F) in the summer. I measured temperature drift before processing film by simply leaving a tray of water out for the developing time, and agitating test sheets in it at the same interval as I would when really developing. (With a tank, you could simply fill it and agitate as usual for your developing time). I used a water tempering bath (larger tray). At the end of developing time, I measured the difference. It was much smaller than I expected, just a couple degrees. So I adjusted my developing time using the Ilford table and choosing the development time halfway between the starting and ending temperatures of my test. All the other solutions drift higher at about the same rate, so the only other temperature consideration was to make sure my wash water was the same as the temperature of the last fixer when I was ready to transfer to the wash.

Filtered tap water is fine and filtering is a good idea, since it removes particulates that can stick to your film! The reason for a distilled water final rinse for film (I mix my wetting agent with distilled water) is that tap water can contain lots of dissolved minerals, which get into the emulsion along with the water. When the film dries, the water evaporates, leaving mineral deposits behind and, if you have hard water, these can really ruin a negative. The distilled water leaches the minerals out so this doesn't happen. If you do have hard water, make sure your last rinse in distilled water is long enough; I like 3-5 minutes.

And BTW TKent, I love your quote from Don Giovanni (Zerlina) in your signature!

Best,

Doremus

[Pere Casals]

Sounds like trying to filter tap water isn't the way to go.
Kent in SD

Water should be filtered to remove water borne particles, anyway a (reusable) distilled water rinse is usually adviced. Xtol has a better preservation if mixed with distilled water that if mixed with tap water that's high in iron content.

A powered Reverse Osmosis filter also provides good water.

[Randy]

I just use tap water (our water source is from a well). I do a soak in distilled water for a few minutes before hanging film to dry.

[jp]

Keep one jug in a warm place in the house and the other in a cooler place, and mix them together in the right ratio to get to a proper temperature.
example: I used to mix 1:1 d76 and the chemistry might have been at 60f, so I'd add some 76f tap water for the 1:1 mix and I'd be at 68f.

Lacking a place to keep a jug warm, 20 minutes before you need it, place it in a tray of hot tap water. That will warm it up enough for mixing options.

[Andrew O'Neill]

Put the distilled water and developer in a tempered bath. If they are really cold, put them in warm water to bring the temperature up, first. That's how I did it in Japan during winter. Summer was a real challenge, trying to cool everything down to 21C. I was constantly making ice. Tap water was 30C and the room I worked in was 36C and quite humid. I thought I died and went to heaven when I purchased a window mounted A/C.
When you have the developer in the SP-445, keep it in a tempered bath between agitation cycles. I use BTZS tubes, so they are always in a tempered bath. Good luck!

[Jac@stafford.net]

I just use tap water (our water source is from a well). I do a soak in distilled water for a few minutes before hanging film to dry.

Randy seems to be right. I have a home distiller and cannot tell if mixing chemistry with hard city water makes a difference, but washing in hard water is highly effective, and a final soak in distilled water (with 1:200 Photoflow) is a definite advantage. (I do not have a water softener)

I have no suggestions for maintaining chemical temps. I use a large aquarium heater, but the tank takes up a lot of bench space.

[mrred]

I have 2 4gal jugs with spigots. One I fill with distilled water (I have a distiller) and the other is tap water. Evgerything is at room tempature.

My tap water is fairly clean with just mostly silt as an annoyance. However the city makes it PH 7.6 to compensate for older pipes. A little high to mix PH controlled chemicals but fine for one shots and rinsing.

[Jac@stafford.net]

I have 2 4gal jugs with spigots. One I fill with distilled water (I have a distiller) and the other is tap water. Evgerything is at room tempature.

I had my home distiller empty into a blue five-gallon water tank, then did not pay attention to it for a few years only to find that its contents evaporated. Some plastics are permeable. Take care.