Paterson tanks - light tight?

[Matt5791]

Silly question - are the Paterson film processing tanks really all that light tight? - I know that they are supposed to be but I always think it looks like light could get in somehow.

Am I just worrying unnecessarily?

Matt

 

[Bob F.]

In practise, I suspect that a small amount of light will get past the light trap - just not enough to fog film during the typical time it takes between loading the tank and the developer getting to work.

Leaving the film in there with the lid off for a long time might cause a problem. How long? 10 minutes? 10 hours? Dunno, never tested it. Just keep the lid on when not pouring or draining and all is fine (without the lid, your hands can get a bit wet when inverting... ). The design is many decades old - I guess that must prove something.

Cheers, Bob.

 

[gainer]

The lid on my old Patterson tank is gray plastic and is not light tight. Without the center post a lot of light gets through. You could probably make the lid light tight with the right kind of paint or a lot of black tape.

 

[Bob F.]

Interesting: all of mine are black - never seen a grey one. You are right about the centre post of course - that is essential for the tanks light-tightness. Without it, fogging would be pretty much immediate.

 

[Brac]

I have never had a problem them with them as far as light is concerned, but they don't seem to be totally "liquid tight" when you invert them in my experience.

 

[zenrhino]

I have never had a problem them with them as far as light is concerned, but they don't seem to be totally "liquid tight" when you invert them in my experience.

That's my main gripe with developing tanks. I'd pay good money for one that didn't leak chemistry.

 

[Huub S]

Interesting: all of mine are black - never seen a grey one. You are right about the centre post of course - that is essential for the tanks light-tightness. Without it, fogging would be pretty much immediate.

They changed their tanks somewhere around 1982. Both models take the same spools and centre posts, but light traps and caps differ considerably. The older ones with a grey cap have a more elaborate light trap, that, though light tight, is difficult to clean. The newer ones have a black cap and are easy to clean. The light trap seems very simple, but i have never had any fogging problems with them.

Huub

 

[pentaxuser]

That's my main gripe with developing tanks. I'd pay good money for one that didn't leak chemistry.

I was looking at a late 1980s photography book in a charity shop today and for the first time in any book I saw a comparison of tanks. The Durst tank with the grey cap came out tops for lack of leaks. The Paterson was criticised for leaks.

FWIW we used Paterson tanks at Leamington College when I was on a C&G basic photography course. Because everyone used inversion agitation, we all used caps which were black and no-one seemed to suffer from light leaks.

Pentaxuser

 

[highpeak]

light leak, NO. chemical leak, yes. I have two of them, one leaks chemical, the other one doesn't. The leak is not that much, should be ok if you put a piece of paper towel under it. Wear glove if you don't want chemical on hands.

 

[discotex]

They changed their tanks somewhere around 1982. Both models take the same spools and centre posts, but light traps and caps differ considerably. The older ones with a grey cap have a more elaborate light trap, that, though light tight, is difficult to clean. The newer ones have a black cap and are easy to clean. The light trap seems very simple, but i have never had any fogging problems with them.

Huub

I've got both types. Neither have given me any problems with light leaks but the older screw-on-top version has a couple of gotchas.

If you don't have the soft plastic ring that sits the top of the tank just inside the thread you might find you a) have a very leaky tank - that's liquid - and b) you can't get the top off.

I had to tear one apart with pliers to rescue two films after I forgot to insert the ring. It had developed a crack in the base and it was a $2 second hand one so I didn't mind.

The old design is more of a pain to load in a changing bag.

The newer design is far superior in all respects. Easier to load in the dark, quicker to fill and empty, easier to clean and easier to dry.

I'm sure it's just as light tight as long as you secure the internal lid correctly. By that I mean you should wiggle it before you click it into place to make sure it is sitting evenly the whole way around. Apparently as they wear it's possible to feel it click into place without it being fully sealed.

..Matt

 

[Paul Sorensen]

As for the chemical leak issue, I find that if you burp the lid before agitating far less chemistry will leak out, sometimes almost none. We have dozens of them and certainly some lids are better than others but all will benefit from a good burping.

To burp the lid, press the base of your palm against the middle of the lid and pull open the edge a little, letting a little bit of air out. This creates a negative pressure that improves the seal greatly.

 

[argus]

Paterson tanks with a grey lid are of the older type.

I don't have any problem with leaking Paterson tanks since I use Rodinal and never rotate the tank 180 degrees while agitating.

Anyone thinking that light might enter the tank through the center collumn, is prone to mental health care. Visit your shrink now, you might suffer paranoia.

G

 

[johndeere]

I use the newer version of the tank and I seldom place the cap on top of the tank. I often load the tank and let it sit out for over 24 hours without the top cap on. Todate I have never had an issue with fogging, so I can safely say if you have the inner funnel correctly in place the issue of light leak is nill.

I too burp my caps and seldom have a problem with a chemical leak issue.

I do like the newer version tank over the older tanks with the lid that twisted on like a jar cap.