PDA

View Full Version : Gadget for use of steel tank with 4x5 film



chrism
4-Jan-2015, 17:21
I have done all of four developments with two 4x5 negatives each time, so please dismiss this as you see fit! I'm adapting my 35mm and medium format gear and practices to large format film. I don't have a dedicated darkroom, but can make a small washroom light tight temporarily. There isn't much counter space there. My four sessions so far have used either a 3-reel Paterson tank with two 4x5 negatives in it, or a 4 reel steel Samigon tank with two negatives. I tried the doing 'taco' method once but wasn't happy with manipulating the negatives into hair bands that weren't quite long enough, so I gave up and just put the negatives into the tank in the usual fashion. Two of the four times the negatives have slid around inside the tank until one sits atop the other. This hasn't affected development (not at all, which surprised me), but each of those two times one of the negatives has been scratched as a result. So tonight I came up with a kludge that might help out. I didn't want to spend $92 on the MOD54 as my 3-reel Paterson tank takes more developer than the narrower steel Samigon tank (http://www.bhphotovideo.com/c/product/122983-REG/Samigon_ESA347_Stainless_Steel_Tank_with.html) (tall 4x35mm reel version), I only do two negatives at a time so far, and, finally, $92? $92 is cheaper than making a permanent darkroom, but since I know my presence here isn't permanent I have to make compromises.

So here is what I did. I found the biggest wire coat hanger in the laundry room, made of the thickest, springiest wire of any available there. I pushed one 'shoulder' of the coat hanger into the tank and found it would go all the way to the bottom, and was wedged in pretty tight. I then snipped the wire just above the top of the tank and used pliers to bend the ends towards each other so that they should meet, but at a level that sits below the top of the tank such that the lid can still be seated into place. Then I snipped the two horizontal portions so that they didn't overlap and cut a straight portion of stiff plastic drinking straw (the kind that has various knots and circles in it for kids that is re-usable) and placed it over both ends of the wire after removing it from the tank. A couple of adjustments and I have the straw only just fitting into the tank with the wire ends in it. If it helps to think of it this way, I have ended up with a not-terribly symmetrical hyperbola of springy wire jammed into the tank, with the (near) vertical portions of each side making a 90 turn towards each other and contained in a section of rigid plastic tubing. It is still easily removed for cleaning. The only issue I can think of is that the plastic straw might hold inside it a little chemical that will contaminate the next stage of each part of the development. If I had some heat shrink tubing I could probably avoid that (but at the cost of restricting the springy movement of the wire that keeps it pressed outwards against the tank walls, and I think this matters as a negative slipping under the wire will likely get scratched).

I'll try it out tomorrow, as long as there is time before I set of for the city and my next cycle of chemo (snow in the forecast might screw that up, which would involve a delay of a week if I have to set off early). I don't think a pair of sheets of 4x5 on either side of this wire will be able to pass it as it is sprung tightly against the tank walls. If it works I will take some pictures as it is stupidly easy to make and may save me some money! The owner of the plastic straw assures me he has not been permanently harmed by my abuse of his property, and he was concerned that I might use his K'nex for the job, so all is well ethically speaking. :)

Chris

Light Guru
4-Jan-2015, 21:06
Could you post a photo of this contraption? I can't quite figure out how it looks.

Jac@stafford.net
4-Jan-2015, 21:59
Very clever! I look forward to your results, and a picture of it if possible.


The only issue I can think of is that the plastic straw might hold inside it a little chemical that will contaminate the next stage of each part of the development.

If you are doing black & white, then the stop bath and fixer will overwhelm and neutralize the bit of developer the straw captured.

Good luck with the chemo, too.

Jac

chrism
5-Jan-2015, 06:43
Sure, here are pictures (don't shoot me for taking them with a digital camera!) First the end of a thick wire coat hanger, cut off, bent inwards at the cut ends and trimmed, with the length of plastic straw in place:

https://farm8.staticflickr.com/7526/16205173035_30899c0dc4_c.jpg

Putting it into the tank:

https://farm9.staticflickr.com/8625/16203298721_ca371af847_c.jpg

Seated right down:

https://farm8.staticflickr.com/7527/16019071999_fd380dbbd4_c.jpg

It's quite a tight fit, and the curved sides are in contact with the walls of the tank. A 4x5 negative slides down on either side, emulsion facing inwards, and the curvature of the tank is such that there is space between the back of the negative and the wall of the tank so liquid can flow around that side of the film too. If the negative tries to rotate around the wall of the tank it comes up against my gadget and can go no further. In the last picture the negatives aren't pushed all the way down, just to make them easier to see:

https://farm9.staticflickr.com/8670/16019487977_d6dff774bf_c.jpg

Chris

WayneStevenson
5-Jan-2015, 06:55
I have been processing 4x5 for a few years using the method of just placing them in the tanks. Never had any problems with them touching or scratching. Perhaps your agitation was a little rough?

Only problem I have had was them riding up the walls during agitation so I make sure I put enough developer in so they'll always stay submerged.

Will Frostmill
5-Jan-2015, 07:08
Sure, here are pictures (don't shoot me for taking them with a digital camera!) First the end of a thick wire coat hanger, cut off, bent inwards at the cut ends and trimmed, with the length of plastic straw in place:

https://farm8.staticflickr.com/7526/16205173035_30899c0dc4_c.jpg

Putting it into the tank:

https://farm9.staticflickr.com/8625/16203298721_ca371af847_c.jpg

Seated right down:

https://farm8.staticflickr.com/7527/16019071999_fd380dbbd4_c.jpg

It's quite a tight fit, and the curved sides are in contact with the walls of the tank. A 4x5 negative slides down on either side, emulsion facing inwards, and the curvature of the tank is such that there is space between the back of the negative and the wall of the tank so liquid can flow around that side of the film too. If the negative tries to rotate around the wall of the tank it comes up against my gadget and can go no further. In the last picture the negatives aren't pushed all the way down, just to make them easier to see:

https://farm9.staticflickr.com/8670/16019487977_d6dff774bf_c.jpg

Chris
Well that's clever as heck! Good job.
Also, glad to hear the knex is safe

Jac@stafford.net
5-Jan-2015, 07:24
I really don't know what to make of the invention. It is too simple, insanely economic, elegantly functional, and worst of all, I did not think of it! Talent! That's it! Talent is just a cheap trick!

Thank you for sharing good stuff.

j

Liquid Artist
5-Jan-2015, 08:37
I also use the same method, and have never had the film move. However I like your device and think it will make it easier setting the film in place. I am always cautious to not overlap the sheets.

I am also thinking. A tab on both sides may hold the film just enough to help slide it out.

Jim Noel
5-Jan-2015, 08:58
Who said ingenuity is dead? This is a terrific solution to a problem.

Will S
5-Jan-2015, 09:33
Very nice! Would something like btzs tubes work in your bathroom?

towolf
5-Jan-2015, 11:54
This is how I solved it some time back:

https://i.imgur.com/QJ7RMDo.jpg

Advantage is, only very little developer is needed.

Only problem is that the film base at the back isn’t wetted and some anti-halo remains. I usually dip the film into developer afterwards which dissolved it. Still need to find out what dissolves the anti-halo of E6 film. It’s not just alkalinity or acidity I think.