[Cuchulainn]

As I mentioned before, the bathroom in our new place in Oxford is not a good place to dry negs - there's just too much dust no matter what I do. So I took matters in hand and built a home made negative dryer. It's worked a treat on the rolls I put through it this week - next to no dust and negs pretty much completely dry in 90 mins or so. Certainly good enough to get into the archive sheets and under a book to flatten them. Total cost was about £30, though it could probably be done for less. I'll stick pics of the setup at the end of the post.

I used a 2m length of 110mm waste pipe that I cut down to just under 180cm to make it more manageable. 3 L brackets and some offcuts of wood made some simple feet to exhaust the air. The film clips were hung from a piece of 4mm aluminium rod that I drilled some holes for about 15mm from the top of the tube. One change I'd make here is to swap the tube for some teflon rod as it's not scratched any films, but I'm paranoid it might. I'll probably wrap it in ptfe tape just for peace of mind.

The actual dryer bit is made from a 150mm square section inspection piece that fits over the pipe. I cut some ply to fit in the top section and cut a circular hole in the middle to work with a 12cm computer fan. I got the fan (a 12V model) from Maplin along with an air filter to prevent the fan sucking in dust and a suitable 1A 12V dc power supply. The insulation tape is just to seal any small gaps since I didn't seal everything with glue in this model in case I wanted to change something. I'd probably just seal it all with bathroom sealant in another version. In hindsight I'd get a multi voltage power supply and run the fan at 9V to slow it down a bit and avoid any possibility of water streaks (I had one small one, but it cleaned off ok) due to the air flow speed. As a compromise on this one, I've picked up some vacuum cleaner filters from a poundshop and I'll cut one to fit and mount it after the fan to slow the air down a bit - we're mainly looking to have a small positive pressure in the tube to prevent dust making its way in from the bottom along with enough of an air flow to keep fresh dry air moving over the film to dry it.

The main problem with it is loading the film - it's done from the top and while the 110mm pipe should allow a couple of rolls of 35mm or 120 to be done at once, you do need to be careful. If I had access to a table saw I'd cut a 1m section on a chord at 80% of the diameter (i.e. enough offset that the hanging rod is still nicely mounted across the pipe centreline) and hinge that. The pipe could then be sealed with masking tape or somesuch once the film is loaded.

Let me know if anyone builds one, I'd be interested to see any other improvements people think of. Oh, and if anyone does have access to 5 or 6mm teflon rod stock, then I'd really appreciate a 150mm length

Pictures:
Top part of pipe with square section and fan mounted. You can just make out the aluminium rod on the upper left of the black waste pipe (it's level with the top of the flash reflection in the door)


Top view of fan unit showing mounted air filter


View from bottom of fan unit showing fan and simple ply mount

[TomB_tx]

Very Nice! I've been thinking of doing something similar, in setting up my darkroom again after 25 years. I used to have a filtered-air darkroom in my last house, but now...
I also used to use a "film dryer-conditioner" solution as a final rinse that used an alcohol base, so that the film dried in a minute or so. But that type of product seems to have faded away.

[Cuchulainn]

Thanks! I had seen various products mentioned that could speed drying, but none of them seem to be on sale nowadays, so I took matters into my own hands!

[Marc Sabatella]

Moved to film processing and darkroom forum.

[tuco]

Nice dryer.

I steam up the bathroom using the shower for a short period, hang the negatives with a small fan blowing on them and close the door. It works fine too when you can do that. Film is dry in about 1/2 hour or less.

[whojammyflip]

Yeah, I vacuum our house so that its less dusty

Seriously, the streaking is something which shouldn't happen really. Maybe you need to wash the film more. And then, maybe washing the film thoroughly makes dust less likely to stick to it? I am based round the corner from you, so cannot believe our water is that different.

[HGMonaro]

do your final rinse in distilled/de-ionised water with 1 or 2 drops (much less than the recommended strength) of wetting agent (PhotoFlo or similar) and you shouldn't get any drying streaks. I usually just hang my films up over my sink and walk out but if i have to use the dark room I have a section in my cupboard that I can hang them in.

[Cuchulainn]

Thanks all. The streaking is happening with photoflo in the final wash. Since this is forced air drying and the fan is a bit too strong, I'm not surprised or worried about it - I've got the extra filter discussed, so will give that a go and if there's still a problem I'll stick a resistor into the circuit to drop the fan voltage and all should be OK again!

[stevebrot]

do your final rinse in distilled/de-ionised water with 1 or 2 drops (much less than the recommended strength) of wetting agent (PhotoFlo or similar) and you shouldn't get any drying streaks. I usually just hang my films up over my sink and walk out but if i have to use the dark room I have a section in my cupboard that I can hang them in.

...basically my practice as well.


Steve

[tuco]

Thanks all. The streaking is happening with photoflo in the final wash. Since this is forced air drying and the fan is a bit too strong, I'm not surprised or worried about it - I've got the extra filter discussed, so will give that a go and if there's still a problem I'll stick a resistor into the circuit to drop the fan voltage and all should be OK again!

Give some thought to having the fan sucking the air out of the chamber on the bottom with the air coming in through the filter on top.

I've been trying to think why, in all my time film developing, I can only recall about one incident of water spots on my negatives. I live an an area with good water and I'm wondering if that helps a lot.

My process is to use a couple of drops of wetting agent after washing. I put on the negative clips, hold the film at arms length and shake it in a rolling wave that travels from one end to the other whipping off excess water.

I do an initial view of the negatives holding them up to the light. Almost always there is what looks like a dark spot of dust or something on it somewhere. I turn on the water in the sink and pull the roll through the running water on both sides. It kind of washes off the wetting agent. But I really shake it good so no big drops of water are on it and hang to dry. I turn on one of those small desk fans and aim it up to blow along the length of the film on the emulsion side (dries quicker it seems) and I get really clean, dry negatives.

And that is the cleanest they will ever be. I amazed when I go back and scan a negative shot only 6 months ago how much really fine dust is on them while being stored in those archival sleeves in a three-ring binder on a shelf. So small and fine I can't really even see them while trying to blow and clean it. It's to the point I'd be better of rewashing it before a scan to save on a lot of healing tool work.

[stevebrot]

I live an an area with good water and I'm wondering if that helps a lot.

It does. Although you and I live in the same rainy region, the good people of my water district chose to drill wells rather than use surface water from the mountains. My water is heavy-laden with both silica and carbonates and a final rinse with distilled water/Photoflo is a must to avoid nasty spotting. You have to take it easy with the Photoflo though to avoid scum.


Steve

[stevebrot]

I amazed when I go back and scan a negative shot only 6 months ago how much really fine dust is on them while being stored in those archival sleeves in a three-ring binder on a shelf.

I think that there must be some sort of fundamental force that draws dust to negatives. I have had much the same experience!


Steve

[jford]

Nice idea. Not planning to get back into film, but this brings back memories. At least, the talk of dust does.

[HGMonaro]

The streaking is happening with photoflo in the final wash.

is this in distilled/de-ionised water?

[ChrisPlatt]

The basement darkroom I once had was plagued by dust.
A negative ion generator really helped in solving the problem.
It was a Amcor Modulion and cost about $30 around 1980.

Chris