Pre-soak or not?

I only pre-soak with old school emulsions like efke 25. In my experience i get a lot more longitudinal curl if i pre-soak modern emulsions
 
marke said:
Excuse my ignorance, but what exactly is antihalation coating?

Ever so often I do get a bit of a purple cast, but I thought that was either do to a spent fixer or not enough washing.

Thanks.
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http://en.wikipedia.org/wiki/Anti-halation_backing

Ever make a photocopy of newspaper article on the photocopy machine and you can kind of see what was printed on the back of the paper too? That's what is happening. The light is strong enough to go THROUGH the emulsion, out the back of the film, bounce off the film pressure plate (usually black and shiny) and back through to affect your emulsion from the other side.

Because it is something that really old films didn't have sometimes, there are people who prefer the look of a film without an anti-halation coating. It definitely has a 'look' to it, but I'm not sure there is any made any more.
 
bmattock: Thanks. That link explained pretty well. Do you think the purple cast is the unremoved remains of this coating?

colker: Obviously you have enough time on your hands for such an immature reply.
 
Because it is something that really old films didn't have sometimes, there are people who prefer the look of a film without an anti-halation coating. It definitely has a 'look' to it, but I'm not sure there is any made any more.[/QUOTE]

The chinese made Lucky 100/400 had very little or no anti-halation backing. In strong light it can give a bit of a "halo" around bright subjects. Couple it with an old uncoated lens and it can get quite dramatic.
 
marke said:
Do you think the purple cast is the unremoved remains of this coating?
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Could not tell you, since I don't presoak. I have seen what I took to be a dark purple pour out of my developer when I was doing some film or other. Might have been HP5, can't recall. Sorry, I'm color-blind. I seldom notice.
 
marke said:
bmattock: Thanks. That link explained pretty well. Do you think the purple cast is the unremoved remains of this coating?
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Marke,

I do think the purple case is the remaining of the coating. I look at my old films eventually these turned a little yollowish. The developed file that have them are either TMX, or TMY (bought and developed about 10 years ago).

Do you still see this purple cast after pre-soak? When you drain the pre-soak water, you will notice that it is blueish/purpleish clear water.

-PB

PS: bmattock thanks for the link.
 
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Tom A said:
Because it is something that really old films didn't have sometimes, there are people who prefer the look of a film without an anti-halation coating. It definitely has a 'look' to it, but I'm not sure there is any made any more.
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The chinese made Lucky 100/400 had very little or no anti-halation backing. In strong light it can give a bit of a "halo" around bright subjects. Couple it with an old uncoated lens and it can get quite dramatic.[/quote]


If only I could get ahold of some Lucky 100/400 for testing, I have a hunch that the films Ultrafine sell are made by Lucky. Its a very thin film and from what I've shot, have little anti-halation coating. I know its not rebadged Foma since they stopped selling it and introduced a new "plus" line.
Plus, I've called photo warehouse and when asked about the origins of the film they said "the orient".
 
I don't pre-soak 35mm films. The purple cast on T-Max films says it needs more fixing - general rule is to double the fixing time. If the fixer leaflet says 3 mins, I leave it for six mins.
As for 120 films: I put them into the water but not for pre-soaking but to wash away the nearly black mask the back of the film is coated with. It is not neccessary - I just like doing it ;)
When I don't wash 120 films the dark cast disappears during development without traces. Strange...
 
The pinky-purple cast is usually leftover sensitizing dyes. These are removed (to varying degrees) by longer fixing; longer washing; and exposure to bright light.

Then there is film base colour. To check this, when you take the film out of the developer, scrape off a little emulsion from the leader with your thumbnail. If the colour comes away, it's in the emulsion; it it doesn't, it's base colour and ain't gonna come away.

Tashi delek,

R.

Tashi delek,

Roger
 
I only presoak with Efke's Infrared film. I read to do it somewhere and do it. iirc it has to do with the antihalation backing. You presoak and it takes off the backing so it won't potentially react with the developer. When you go to dump out the water from presoaking, it's a indigo color, almost like ink.

I decided presoaking regular films might be a bad idea because even though I clean my developing tank, I'd hate to have some of my film ruined due to some residual fixer in the reels or whatnot
 
Never used to do it, but Sprint recommends it, and in fact when using Sprint developer, my students get much more even development if they pre-soak.
 
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