Niall.
with 35mm film it does not always make sense but with sheet films the pre-soaking has two effects:
1) The antihalo layer will be removed (nothing really special as the developer could to this to)
2) the supercoating will be washed off
Now number two is what we are looking for. The supercoating is a thin layer of highly diluted gelatine which is applied to the film after emulsioning for the purpose of protection. It can?t always be applied 100% evenly because it is very liquid. This layer we want to completely remove in the developing process so the developer can acces the film?s surface with the same speed everywhere. If this is not removed completely after development some larger format sheet films can show slight streaks.
In the enlarging process this would still be almost invisible but if you do contact printing (and that?s what most of these big sheet film users do) this can show on the image.
As for 35 mm I cannot see why one should presoak unless there is some special ingredient in the anti halo which might work against the developer or so.
Sometimes people come up with the theory that a presoaked film develops more eqaulized than a non presoaked film due to a slower penetration of the developer into the emulsion (it jas to work its way in by "pushing" out the water already beeing there) but I have never experienced this.
Cheers,
Mirko
PS you can buy all our fancy stuff now of our new parter [url="http://www.retrophotographic.com"]Retrophotographic[/url] if you don?t mind buying of a british company :-)
(Dieser Beitrag wurde zuletzt bearbeitet: 17-10-2004, 03:53 PM von Mirko Boeddecker.)
with 35mm film it does not always make sense but with sheet films the pre-soaking has two effects:
1) The antihalo layer will be removed (nothing really special as the developer could to this to)
2) the supercoating will be washed off
Now number two is what we are looking for. The supercoating is a thin layer of highly diluted gelatine which is applied to the film after emulsioning for the purpose of protection. It can?t always be applied 100% evenly because it is very liquid. This layer we want to completely remove in the developing process so the developer can acces the film?s surface with the same speed everywhere. If this is not removed completely after development some larger format sheet films can show slight streaks.
In the enlarging process this would still be almost invisible but if you do contact printing (and that?s what most of these big sheet film users do) this can show on the image.
As for 35 mm I cannot see why one should presoak unless there is some special ingredient in the anti halo which might work against the developer or so.
Sometimes people come up with the theory that a presoaked film develops more eqaulized than a non presoaked film due to a slower penetration of the developer into the emulsion (it jas to work its way in by "pushing" out the water already beeing there) but I have never experienced this.
Cheers,
Mirko
PS you can buy all our fancy stuff now of our new parter [url="http://www.retrophotographic.com"]Retrophotographic[/url] if you don?t mind buying of a british company :-)
