Paper chemical temperature question

Hallo,

Odd query this but do the chemicals in the b/w printing process have to be close?

I know that in film processing the chemicals should be close together to avoid reticulation of the film - is there any similar or other disadvantage if the chemicals in the print process are not as close as should be.

I ask this because I have a lovely new dishwarmer that keeps the dev at a consistent toasty temp but the stop/fix are still slumming it in a non-heated water bath which does cool down during a printing session. I try to remember to top up the hot water but temp does fluctuate.

Any thoughts?

Sim2.

Sim2,

Chemicals for print processing should ideally be the same. However, they do not always have to be at exactly 20°C. Warmer temperatures (as long as they don't go above 25°C or so) are fine. The developing times (and the reactions in the other chemicals) will be faster, but this usually doesn't present a problem, since papers are developed to completion. For repeatable results, use the factorial method of developing (note the time it takes for a specific mid-tone to emerge use that as a factor of the total developing time. Then, when developing the same print in the same developer at a different temp, you can simply note the emergence time, multiply be the factor and arrive at your (starting) developing time.)

Colder temperatures may work alright if close to 20°C, but much more than an degree or two may affect the activity of the developing agents differently and skew the activity/contrast characteristics of the developer (specifically, hydroquinone loses activity at lower temperatures).

That said, unless you are developing in a cold basement or garage where the temperatures are less than 18°C or so, you should be alright using room temperature for all your solutions.

What you do not want is a wide variation in solution temperatures (e.g., warm developer, cold stop and fix). While paper holds up to variations in temperature better than film, it is still not a good idea.

Hope this helps,

DoremusScudder
www.DoremusScudder.com

Hi, thanks for this.

The print dev is kept fairly constant due to the dishwarmer, it is the stop and fix that tends to drift a bit due to the trays being in a water bath and I know I rather forget to top up with fresh warm water during a printing session.

Just was wondering (apart from activity or usefulness of the chemicals) if there was any obvious damage that can be caused - such as reticulation in film.

Guess I really should spring for another dishwarmer!

I have this problem, too. I get round it by keeping the room temperature close to 18 DegC. I have the dev tray on a dishwarmer set at at 20 DegC. The 2 degree difference will not cause any problems at all. A much greater problem would be a very large difference between the fix and the wash. In this case it may be advisable to have a 'pre-wash' tray of water set between the fix temperature and that of the wash (unless of course you're lucky enough to have temperature controlled washing)

Rob

The developer temperature can have a marked effect on image colour, higher temperatures help increase the warmth of warm tone papers, but care must be taken as some papers will build up base fog if too high.

Conversely for cool tones keep as close to 18-20°C as you can.

Ian

not all developers like it at 68ºF, if you end up using a glycine based developers,
they tend to like to be used at a somewhat higher temperature, around 73ºf ...

I like to use all print devs at higher temperatures but then I'm usually after increased warmth in the darkroom as well as the prints

Ian

For heating dish trays I have find out that heating cables(110 or 220V) for terrariums from pet shops are very practical solution.There is many sizes (lenght/W).Just put cables under dish trays, fill with water and find configuration that keep temp. 20-22°C or you can find "wet" thermostat who can switch on/off heating cable.You need only one cable that can pass twice under all 3 or 4 dish trays.

FRANOL said:

For heating dish trays I have find out that heating cables(110 or 220V) for terrariums from pet shops are very practical solution.There is many sizes (lenght/W).Just put cables under dish trays, fill with water and find configuration that keep temp. 20-22°C or you can find "wet" thermostat who can switch on/off heating cable.You need only one cable that can pass twice under all 3 or 4 dish trays.

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He! he! he! I like this suggestion but know with my luck with electricals I would fairly quickly electrocute myself, a sort of permanent fix! (should point out that I managed to short circut a car battery with a spanner and burnt out the main wiring loom once. :rolleyes: )

Thanks for the considerations and replies, sort of as I suspected - best to keep fairly stable good temps for consistency but no major picture deteriation if the temps do drift a bit.

Anyway, been printing this evening and the "patented" warm water bath under the stop/fix worked fairly well at maintaining a temp similar to the cosseted dev tray with its' personal dishwarmer.

My MO is to take a print from a 70f developer to a 55F (or so) water stop.

You could not abuse prints from temp differentials more than I have (I guess you could set them on fire, that doesn't count) but I have not seen any detrimental effects.

FRANOL said:

For heating dish trays I have find out that heating cables(110 or 220V) for terrariums from pet shops are very practical.

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I use a seed propagating heater. There's no temperature regulation, but with my set-up it always stabilises remarkably close to 20C.

Steve