Brain Storm: Drying "cabinet" for sensitized carbon tissues...
So in my new place I can darken my laundry room when I need to process film and paper, but I can't really keep that room dark for any extended period of time; more than a couple of hours.
But I need a UV-free place for my sensitized carbon tissues to dry. My thought is to create some kind of box or similar thing that I can put the tissues in and store somewhere out of the way.
First thought is to get an under-the-bed rubbermaid storage thing and place a large sheet of metal in it, securing the sheets with magents and storing under the bed. I'd get something that's opaque and put some kind of ventilation in it and maybe even have a small fan to circulate air.
But it needs to be safe, as in chemical contamination, and I guess this shouldnt' be a huge concern since there are no fumes or anything.
Anyways, could use your guys collective brain power to solve this problem.
I use a Technal forced air print dryer to dry my sensitized tissues, and, with different racks, actual prints. It has a fan-only setting, plus a heated setting. It can accommodate up to 11x17 sheets. I have it sitting in a room with a north-facing window with the blinds down and shut, and a relatively thin curtain drawn over it (certainly not blacked-out). Haven't noticed any fogging as a result. Painting the plexiglas cover of it opaque black would probably allow me to be even more casual about where I put it.
With brush sensitization, I typically only need 1.5-2 hours to dry a tissue. With a stronger or more directed airflow, I could probably cut that time down a little more.
I have a cheap metal filing cabinet - the flimsy kind you get at office depot. I hang my tissue to dry and when they feel right I put them into plastic ziploc bags and then into the filing cabinet. I take them out as I use them in the printing session. The ziploc bags prevent them from drying out more as time goes by. This is not long term storage - only for the printing session.
Edit - I use alcohol or acetone to speed the drying of the tissue. Mine will dry in 2-3 hours. If you use thick tissue you may need much longer even with alcohol or acetone
Although I haven't used it for the purpose you are seeking to accomplish, I have an old Burke & James Drying Duo drying cabinet for both prints and negatives. It is 24" X 34" X 12" and has multiple screens to put stuff on to dry. This is not an offer to sell as I have no interest in selling it, however you might keep your eye out for one. It would get you stuff dry quickly and then you could store it in a light tight box. It is a fairly old piece of equipment and probably could be had for a decent price if you can find one. Mine came from a university photo lab. Bill Barber
I dry mine in a cupboard with a dehumidifier running to keep relative humidity to 30-40%.
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Thanks for all the ideas guys. The dehumidifier, or some kind of heating element seems like a good idea, and I think I just need to go thrift shopping to look for the right kind of cabinet.
I use my laundry room for sensitizing also ... and use the clothes dryer for drying the sensitized tissues. Not too practical if you're a high-volume printer but I only sensitize about twice a month at most and only print up to 8" x 10" negatives on 9" x 12" tissues.
I run the dryer for a few minutes to get the interior temperature to around 90 degrees F ... turn it off ... rotate the drum by hand until the vanes align on the bottom so I can put a rack across them ... tape the light switch on the door down so it doesn't come on when I open the dryer ... load the sensitized tissues onto the rack one at a time as I finish each ... wait two hours from when the first tissue went in and start printing.
There is no air circulation or fan to assist with drying but I brush sensitize with acetone and have not had a problem with them drying. The dryer will hold ten 12"x15" tissues at a time ... but the most that I've done at once is eight 9"x11".
For light protection, I use cutouts of amberlith over the windows ... that lets plenty of daylight in but no UV ... rubylith would work too but is a little darker and you get less light to work by.
Last edited by Jim Graves; 09-08-2011 at 10:30 PM. Click to view previous post history.
A brief update to this thread.
Last night I took a vintage paper filer (kinda like this one) and wrapped it with black plastic sheeting. By taping the plastic around the corners I can hopefully keep all the light out, and then a loose flap allows for loading it, using magnets to secure that once it's loaded.
My one concern is getting airflow throughout. I've got a sample of black Tyvek coming, which if it's sufficiently light proof should make a nice "breathable window".
The metal filer is appealing because I can use magnets to attach my carbon tissues, though they curl so strongly I've had to order neodynium magnets! The metal can easily be hosed down too, to prevent any dichromate contamination.
If the black Tyvek is sufficiently light blocking, it might be a good material to use in place of black plastic, since it lets water vapor through.
On the other hand, if it doesn't work, I need to find a better way to get air in and vapor out. Trying to think of some kind of simple light-trap, but so far I'm a bit stumped...
You could consider picking up an old refrigerator for next to nothing (or less) and using trays of dessicant instead of a dehumidifier. If the door gasket is decent, it will be light-tight, and the interior finish lends itself to easy cleanup. For hanging paper, remove all of the shelves but the top one, or install your own hanger bars. For flat storage, use the existing shelves or add your own---with the refrigerant removed and the power cord cut off, you can safely drill into the cabinet to mount things.
If the interior is going to be crowded (we can only hope!) the easy, safe way to get air circulation is to use a 12 VDC electronics fan powered by an AC adapter located outside the reefer. In a closed environment, it won't take much to keep the air stirred up.
Incidentally, if you want to "condition" paper, there are various salts which, when in contact as both solid and saturated liquid, will maintain a constant humidity level until either the solid has dissolved in captured water or the liquid has given up its water to the environment. Much simpler and cheaper than a humidifier/dehumidifier setup with a control loop.