How well do floating lids work

[Mainecoonmaniac]

I'm curious about how well do floating lids work on film processing tanks? Can one store developer indefinitely in a 4x5 film tank without oxidation with floating lids? I know that stop and fix effected too much by air. Am I correct?

 

[BMbikerider]

The lids on my NOVA Processors do very much the same thing but I follow a strict procedure when I have finished printing to make sure they are optimised.

I top up/replenish the developer, stop bath, and blix when I have finished, wipe the edges of the tank dry and then with the floating lids in place, cover the whole of the top of the tank with cling film to make it as airtight as possible. When the solutions cool down, if I have obtained a good seal, the cling film allows a semi-vacuum to form in the tank. (I only worry about the developer) You can tell this has happened when the surface of the cling film which was previously flat, takes on a concave depression.

I have done this for as long as I have been processing colour and the RA4 developer (Kodak Ektacolour) has lasted as long as 18 months so long as it replenished properly. I only need to change it when the build up of tar gets too much.

So yes, in the right circumstances they do work.

 

[georgegrosu]

To give you an idea of keeping processing solutions in pots with floating roof see Kodak recommendations: http://motion.kodak.com/motion/uplo..._en_motion_support_processing_h2415_h2415.pdf Table 15-11 Storage Life of Mixed Solutions and Table 15-21 Storage Life of Packaged Concentrate and Mixed Solutions at 21° to 24°C (70° to 75°F).

George

 

[George Collier]

We used them in the Army with a replenishment scheme. Used once a day for a month or two with DK50 in 8x10 tanks. Now, my standards might be higher today, but it worked and contrast was consistent, or we'd have known it when printing.

 

[Prof_Pixel]

Can one store developer indefinitely

I think 'indefinitely' is the problem word. Nothing last forever. I used to use them on 4x5 tanks and though they worked much better than repeatedly pouring the developer from a bottle to a tank and then back to the bottle (and so forth).

 

[Mainecoonmaniac]

Thanks for the great info. I guess all this pouring between tank and bottle causes oxidation.

 

[laser]

If you want one I listed an 8x10 floating lid in the APUG Classified section.


It will not provide infinite developer life but preventing exposure to the air is the best way increase developer life. This is a tried and proven easy way to increase developer life

 

[Mainecoonmaniac]

If you want one I listed an 8x10 floating lid in the APUG Classified section.


It will not provide infinite developer life but preventing exposure to the air is the best way increase developer life. This is a tried and proven easy way to increase developer life

Thanks! But I don't have an 8x10 tank

It looks like it's in good shape.

 

[presspass]

I have used floating lids on 4x5 tanks with X-tol developer replenished and had it last 18 months. It might have gone longer, but I got nervous. There was considerable buildup of caked/dry fixer around the lid of that tank, though.