Rinsing film

[Photo Engineer]

While I was in London visiting the Kodak facility at Harrow, I noticed the smell of the water and the lack of chlorine in it. I was saying at a hotel on Drury Lane near the White Hart. I was told that they used an oxygen (ozone) treatment for purification.

Thiourea can soften emulsions and increase swell as can urea. Peroxide is used in wash aids IIRC.

PE

 

[KOG]

Don't assume that US water systems haven't used ozone. I know for a fact that the City of Dallas (TX) Water Utilities uses ozone as part of their water treatment program. However, US regulations require that there be a residual chlorine level in the water at all points in the distribution system. That's why you can smell chlorine in US water supplies.

Kevin.

 

[Photo Engineer]

Yes, true. Go here: http://www.dwi.gov.uk/pubs/tap/index.htm#3 for an explanation of the fact that ozone can decay in the distribution system and therefore chlorine is added as an extra precaution.

Also, remember that peroxide is used in hypo eliminators.

In addition, the type of water - hard, soft, distilled, warm, cold and the film thickness all determine wash rates. This is NOT a simple subject.

That is why I say 'test for your conditions' and use what passes the standard test for hypo and silver free film.

PE

 

[Gary Holliday]

Just learned a (for me) new method for rinsing film.....
One fill with water .. 10 times aggregation... second fill and 20 times aggregation ... third fill and 15 times aggregation.....
Somebody called it the ilford way.....
Normally I rinse my film 1/2 hour... it takes a lot of water and the 'Ilford method' much less water. But do any of you know anything about The Ilford way (or is it called something else?)

erik

There are a few threads on this:
(there was a url link here which no longer exists)

I'd recommend leaving your water running for 10 mins or so and dunking the film for 10, 15, 20... times etc and exchanging the water regulary.

 

[Erik Hartmann]

Thansk to all of you for given me some knowledge on this subjekt.....
I think that I will go on using the Ilford Method...
Wather in Copenhagen is free of chlorine and ozone......

erik

 

[Photo Engineer]

Erik;

What do you use for water purification in Copenhagen?

PE

 

[Erik Hartmann]

Ron...found a lot about water in Copenhagen.....
Have to answer when I am back in Copenhagen.... and have to to translate the name of the chemestry from danish.....
But most of the water in Copenhagen comes from underground and need almost no treament.....water is a little hard about 20 degrees (and very good for the)

erik