Small Tray Warmer, uneven development?

Fintan · Jun 8, 2007

I'm on the lookout for a tray warmer for my developer trays. I print mostly 12x16 16x20 and 20x24.

My question is, if I buy a 16x12 tray warmer [one available used I know of] will this cause uneven development on 20x16 and 20x24 prints?

I'm thinking the agitation when developing a print will mix the developer somewhat but I'm unsure if there will be enough motion?

Any comments for my peace of mind?

Fintan

(there was a url link here which no longer exists)

Nick Zentena · Jun 8, 2007

You could always get an aquarium pump. Have the inlet at one end the outlet hose at the other. I did that for the tempering bath I built.

I don't know the warmer you're looking at but the other idea is to stick it in a bed of sand. This way the warmer heats the sand bed which then heats the tray. This way you don't have hot spots when the heater turns on.

dancqu · Jun 12, 2007

Fintan said:
I'm on the lookout for a tray warmer for my developer
trays. I print mostly 12x16 16x20 and 20x24.

Heating pads for terrariums and seed starting should
be explored. Dan

Jim Jones · Jun 12, 2007

A light dimmer can be used with a heating pad for control. It might take time to find the right setting for the desired warming.

Mike Té · Jun 12, 2007

Murray's piglet warmer idea!

I like Murray Minchin's pig warmer mat idea. It's on my wish list for this fall, before things get cold again. You can also get a thermostat for it.

http://www.farmtek.com/farm/supplies/prod1;ft1_hog_equipment;pg106120.html

Apparently it's also manure-resistant

Peter De Smidt · Jun 12, 2007

In Winter my darkroom gets below 55F. To keep my developing tray at the right temp, I use a Kaiser photographic hotplate. To keep my stop and fix up, I use on of the seedling mats. Under the mat, I have a piece of styrofoam wrapped with a mylar reflective blanket.

The hotplate has no trouble keeping the developer at the right temp. Moving the print around in the tray gives more than enough agitation for even development.

The seedling mat gives a fixed rise of about 10 to 15 degrees F. This is enough to keep them at a good temp.

If I could buy more of the Kaiser hotplates, I would.

My next project is to build a big slot-processor out of ABS, and heat it with a Won titaniam heater and an aquarium pump. Hopefully I'll have this up by next winter.

I do have an oil-filled heater in the darkroom. I only turn it on when I'm in there. The trays are right next to a 15" thick masonry wall, which in winter is at about 50 - 55F. Hence the need to heat the trays.

Make sure that the outlets you use are GFI, and use some common sense. (I stand on a rubber mat when developing prints....)

jeroldharter · Jun 13, 2007

Peter De Smidt said:
If I could buy more of the Kaiser hotplates, I would.

QUOTE]

I have not seen these for sale. Are they still available?

I wonder if you could use a thick sheet of aluminum (like the thickness of a good frying pan) on top of the warmer to distribute the heat more evenly. That prinicpal is used in some of the radiant floor heat systems.

I would not want sand in my darkroom. Perhaps small glass beads or marbles would work better.

Peter De Smidt · Jun 13, 2007

I bought the Kaiser Photographic Hotplate off of Ebay a few years ago as New Old Stock. I've done some searching, and I've not been able to find anymore. It works very well. There's no need to make the heat more even. Regular print agitation evens out the temperature very well.

I'm not sure what your comment about sand is in reference too.

Nick Zentena · Jun 13, 2007

I think it's my bed of sand comment.

The bed of sand would hold heat. It means less cycles of heat/cold.

fschifano · Jun 21, 2007

How cold does it get in your darkroom? In winter, mine gets down to about 55F, but warms up pretty quickly with a small space heater. After a short time, I turn it off as the heat from myself and the enlarger is enough to keep things comfortable. I've never had the need for a tray warmer when doing B&W work.

Peter De Smidt · Jun 21, 2007

My darkroom gets down to between 50 and 55 F in winter. A space heater does help (an oil-filled radiator), but the sink is next to a 15" thick masonry wall. The outside of this wall is exposed to the elements, and hence the wall gets very cold.

jeroldharter · Jun 21, 2007

fschifano said:
How cold does it get in your darkroom? In winter, mine gets down to about 55F, but warms up pretty quickly with a small space heater. After a short time, I turn it off as the heat from myself and the enlarger is enough to keep things comfortable. I've never had the need for a tray warmer when doing B&W work.

Some toners, like brown towner and gold toner, work much more quickly when the temperature is about 100 degrees and take forever at room temperature.

Also, some people like to standardize development temperatures above room temperature because it is easier to keep the tanks warm that it is to cool them off.

Small Tray Warmer, uneven development?

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