How Hard Should You 'Tap' Canister When Processing Film?

Vaughn · Oct 20, 2020

I have SS lids for my double 120 reel SS tanks. They are sweet. The less plastic the better.

The tanks fill/empty fast -- tilted the lids allow air to escape while liquids go in (or out). I use a water bath before developing because of the distance the developer does have to travel to the bottom of the tank.

Agulliver · Oct 20, 2020

Two taps on the bottom of the porcelain sink, careful not to tap sufficiently hard to damage the tank but with enough force to dislodge bubbles. I was taught this something like 40 years ago by my father and 35 years ago by my photography/darkroom teacher at school. The latter showed the class the results that can happen when not tapping and I'm pretty sure that I've had the same myself when I've forgotten to tap.

I've always used plastic tanks, Paterson or similar in my school days and a Jobo at home. I now also have a Paterson style tank. Never had any issues loading the reels except for one especially stubborn roll of 35mm HP5+....I never got to the bottom of why that roll just wouldn't load. I snipped the end of several times to present a different edge to the reel...nope...it just refused. Bad tempered bit of film, that one.

PFGS · Oct 20, 2020

Vaughn said:
I have SS lids for my double 120 reel SS tanks. They are sweet. The less plastic the better.

The tanks fill/empty fast -- tilted the lids allow air to escape while liquids go in (or out). I use a water bath before developing because of the distance the developer does have to travel to the bottom of the tank.

I'm with you on less plastic, and I know my plastic lid will wear out eventually. I also have all-steel tanks, nice old Nikors, but the problem I've had with them is the little cap over the pour-hole seizes to the main lid and fighting with when "time's up" is nerve-wracking - is there a fix for that?

Donald Qualls · Oct 20, 2020

PFGS said:
I also have all-steel tanks, nice old Nikors, but the problem I've had with them is the little cap over the pour-hole seizes to the main lid and fighting with when "time's up" is nerve-wracking - is there a fix for that?

Keep a screwdriver on the darkroom counter. Put it under the edge of the little cap and twist. Cap will come right off.

NB23 · Oct 20, 2020

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PFGS said:
Vaguely related question - why agitate at the start? The developer is fresh, why this prolonged agitation right up front? For me, usually a lot of that 30 seconds is taken up by filling the tank and I only get a few agitations in anyway.

Especially at the start, all the air bubbles are trapped right between the film’s sprocket holes and the contact between the film and the reels. Pouring the developer is not enough actuon to displace all the trapped air.

PFGS · Oct 20, 2020

Donald Qualls said:
Keep a screwdriver on the darkroom counter. Put it under the edge of the little cap and twist. Cap will come right off.

'Tis the kitchen counter, hence the tidy pour. But that sounds like a perfect use for one of the many stubby screwdrivers that seem to breed in the dark corners of the shed.

NB23 · Oct 20, 2020

I will usually let the ss tank slip from my hand onto the counter from about 6” high, twice. This does it for me.

Donald Qualls · Oct 20, 2020

They don't breed in there, they migrate. I never seem to have one of those.

PFGS · Oct 20, 2020

Donald Qualls said:
They don't breed in there, they migrate. I never seem to have one of those.

Maybe I have yours, and you have all my #1 Philips I can never find?

monst · Oct 20, 2020

We really do overthink stuff at times...

foc · Oct 20, 2020

monst said:
We really do overthink stuff at times...

Agreed

Will tapping the tank be the next, "should I prewash / squeegee / washing up liquid V wetting agent?"

Vaughn · Oct 20, 2020

PFGS said:
I'm with you on less plastic, and I know my plastic lid will wear out eventually. I also have all-steel tanks, nice old Nikors, but the problem I've had with them is the little cap over the pour-hole seizes to the main lid and fighting with when "time's up" is nerve-wracking - is there a fix for that?

Don't push it on too tight. I do my inverts with a finger on the cap tp keep it on. Does not leak. Have a coin or something to give the cap a little push to come off. Does not take much.

PS...What Donald said...

MattKing · Oct 20, 2020

monst said:
We really do overthink stuff at times...

While this is true, the question posed in this thread is a perfect example of the sort of thing that used to be easy to learn - in person, from someone who knew the answer through experience and could show you - and is now relatively difficult to learn, because even with all the technology available the internet doesn't quite do the job as well.

pentaxuser · Oct 20, 2020

MattKing said:
, the question posed in this thread is a perfect example of the sort of thing that used to be easy to learn - in person, from someone who knew the answer through experience and could show you - and is now relatively difficult to learn, because even with all the technology available the internet doesn't quite do the job as well.

True and it might explain why there are several successful( in varying degrees) photography forums but no brain surgery ones

pentaxuser

grat · Oct 20, 2020

The internet is more useful for brain surgery than you think... I used to do IT support at a neurosurgery department. One of the doctors there I learned later, not only literally wrote the book on brain surgery techniques, but designed a number of tools for brain surgery. There is a large collection of his lectures, techniques and 3D models on the internet, free for use. Very good guy, who sadly passed away a few years ago.

Brain surgery is a funny thing-- they keep the patients awake so that if they make a wrong turn, they get instant feedback (ie, the patient start speaking gibberish, their vision goes wonky, that sort of thing).

How Hard Should You 'Tap' Canister When Processing Film?

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