Homemade Film Drying Cabinet Question

[brian steinberger]

I recently built a film drying cabinet out of melamine and just the other day got the first chance to use it as my new darkroom is now finished. The film dries in a reasonable amount of time however it has a slight buckle or wave down the straight edge of its length. The cabinet is basically a locker with furnace filter material at the bottom and top. This is the only airflow I have. No heat.

My question is do I need more holes like in the sides and back? Will this promote more even drying? (Is this the issue?) or do I need to introduce heat? Like a lightbulb. I've previously air dried my negs from a line and never had a buckling problem.

I've attached some pics of the cabinet. Thanks!

 

[fotch]

Nice job. Myself, I would use mild heat, either a hair dryer or light bulb. I think the heat will insure the air is dry, relative to the non heated air.

 

[fotch]

The quicker it drys the less likely contaminates will stick to the film.

 

[brian steinberger]

Thanks I'm thinking about putting a porcelain light socket on the bottom in the back wall with a 100w bulb in it on a timer. I think that would work. I just wanted to make sure this would solve my problem as I know there are those who advise against heat.

 

[Rick A]

Put a sheet metal diffusion plate just above the light bulb so it heats up, it will disperse more heat and help dry faster.

 

[wildbill]

mine has zero airflow, just a 150w light bulb at the bottom with a piece of aluminum foil pinned to the cabinet walls above it to protect the bulb. no problems, no dust.

 

[brian steinberger]

Excellent. So you guys thinks my problem is lack of air flow that is causing the buckling?

 

[randyB]

Yours is almost exactly like the one I built. I have a 60w light bulb at the very bottom and a small table top fan at the top. The fan is laying horizontal so the air is pulled up thru the cabinet. The fan shroud fits into a mask so the air has to come up from the bottom. Fan and bulb are connected to a timer. My film dries in about 20 minutes.

 

[randyB]

Excellent. So you guys thinks my problem is lack of air flow that is causing the buckling?

buckling or curving of the film is usually caused by the film not being completely totally dry. It may feel dry to the touch but is not completely DRY dry. Some moisture will still be in the base on a microscopic level. Adding heat and air movement will make it dry-dry.

 

[brian steinberger]

Ok great. Wouldn't a light bulb alone be enough to create air movement? Put the light at the bottom and the hot air would rise pulling fresh air in from bottom.

 

[wombat2go]

Brian,
Neat job!
My 'hutch" uses the furnace filter with a downdraft fan but no heat.
I have been hanging the film vertically.
The humidity meter in my darkroom varies from less than 10% in winter to more than 80% in summer.

With C41, sometimes the droplets run down and contaminate the lower frames with a concentration of stabilizer.
So I am thinking of laying the strips on edge in a dish, or even leaving them in the spiral till dried.

 

[randyB]

Ok great. Wouldn't a light bulb alone be enough to create air movement? Put the light at the bottom and the hot air would rise pulling fresh air in from bottom.

Yes it would. The fan just speeds things up a bit.

 

[snapguy]

not sure

I am not sure any of us can give you the definitive word on what will work in your case because the weather, humidity,and so on are particular to your part of the world and is most likely not very much like other folks' areas. I live in the desert and film dries real good. I just hang it up in my bathroom. But I would not suggest this solution to you or anyone outside the desert. I would try the lightbulb solution first and then add a blower if you think you need more. Good luck.

 

[wildbill]

just put a porcelain socket on the botttom with a bulb in it and be done with it! I like the piece of metal above the bulb idea instead of my shitty aluminum foil.

 

[removed account4]

i made a drying cabinet by repurposing a plastic closet/storage cabinet from home depot.
no heat source, no light bulb, just something to hang the film on, and doors that close to keep the dust out.
the film will dry when it dries, and doesn't really need the aid of heat ...

i would be very careful putting an electrical socket+bulb on the floor of your drying cabinet ..
water drips off of drying film, and water and electricity don't really play very well.

 

[DWThomas]

If you have room, I would recommend using two lightbulbs in series. That way they are less bright, less hot and will run forever -- a sort of gentle approach! I did that in a metal box I used to dry photo resist on circuit board material decades back.

 

[brian steinberger]

i made a drying cabinet by repurposing a plastic closet/storage cabinet from home depot.
no heat source, no light bulb, just something to hang the film on, and doors that close to keep the dust out.
the film will dry when it dries, and doesn't really need the aid of heat ...

i would be very careful putting an electrical socket+bulb on the floor of your drying cabinet ..
water drips off of drying film, and water and electricity don't really play very well.

This is pretty much what I have now. But my film is slightly buckling when it dries, something I've never had before when hanging from lines in the open. I need to increase airflow somehow.

 

[brian steinberger]

If you have room, I would recommend using two lightbulbs in series. That way they are less bright, less hot and will run forever -- a sort of gentle approach! I did that in a metal box I used to dry photo resist on circuit board material decades back.

Interesting approach. Thanks Dave!

 

[Rick Jones]

In my experience air flow has been more important than heat. You might consider a small fan below the upper filter material to direct air down over the negatives. This would make the lower filter unnecessary and substantially increase the air flow. This is the way my Durst UT100 is setup and it works like a charm.

 

[fotch]

Most if not all commercial units will have both temperature controlled heat, a fan, and a timer.

 

[removed account4]

This is pretty much what I have now. But my film is slightly buckling when it dries, something I've never had before when hanging from lines in the open. I need to increase airflow somehow.

buckling ..
thats weird ... i guess i have to count my lucky stars ... never had that problem ..
i only dry 4x5 film in the cabinet
135 + 120 hangs freerange, from the ceiling with clothespins from a string
i put a clothespin on the bottom too ...
i either hang them and make a few prints &c or leave the room until they are dry ..

good luck with your cabinet !

john

 

[nbagno]

Film twisting

I made a cabinet out of a plastic storage thing I found at the local hardware store. I think it cost me about 70 usd. I put a jobo drier on top and cut some round holes in the bottom. What I have found is with the heat turned on, the top of the film dries before the bottom and causes the film to twist. Even if I just use the fan setting w/o heat the film will twist. Until I figure something out, I just pre-heat the cabinet and let it dry w/o turning on the fan. Dries in an hour.

 

[brian steinberger]

I made a cabinet out of a plastic storage thing I found at the local hardware store. I think it cost me about 70 usd. I put a jobo drier on top and cut some round holes in the bottom. What I have found is with the heat turned on, the top of the film dries before the bottom and causes the film to twist. Even if I just use the fan setting w/o heat the film will twist. Until I figure something out, I just pre-heat the cabinet and let it dry w/o turning on the fan. Dries in an hour.

Is your heater in the top unit as well? I would think the hot air would just go to the top and never fully heat the cabinet uniformly. I'm going to put a light bulb down low in mine tonight and see what happens. At worst I may just need to add a small fan.

Thanks guys for these responses!

 

[Rick A]

It doesn't take much heat, actually the minimal heat generated by a light bulb in the bottom of the cabinet merely causes air currents which dries the film. You need air flow more than heat. My experience is, drying film too fast causes curl and or cupping, even seen twisting(as mentioned in a previous post). Consider the cabinet as a safe place to store film while it dries rather than a dryer.

 

[brian steinberger]

It doesn't take much heat, actually the minimal heat generated by a light bulb in the bottom of the cabinet merely causes air currents which dries the film. You need air flow more than heat. My experience is, drying film too fast causes curl and or cupping, even seen twisting(as mentioned in a previous post). Consider the cabinet as a safe place to store film while it dries rather than a dryer.

Thanks Rick. This is why I was curious if I should just drill some holes in the side and back of the cabinet for more air flow.