Pre Wash....

aggiezach · Dec 28, 2004

So I went to develop some Ilford HP5+ 400 last night and as I was pouring out the prewash water I noticed that is was a nice shade of bluish green... I don't think this affected the negatives (no sign yet) but I was just wondering if this is normal? I soaked the film in the prewash for about 30-45 seconds with constant agitation... Did I do something wrong or is this ok?

Thanks for the help

Zach

motcon · Dec 28, 2004

it's normal; no worries.

oriecat · Dec 28, 2004

Different films come out different colors. It's the anti-halation layer coming off, so it's a good thing.

will965 · Dec 30, 2004

whats the pre-wash. is it after development or fix

sbalsama · Dec 30, 2004

Pre-Wash is just letting the film soak in some water for 10 or however many minutes before pouring the developer in. I personally don't do it since no one has presented a decent reason to do so yet.

terri · Dec 30, 2004

I do it simply because that's the way I was taught. Supposedly it softens the film emulsion and gets it to swell, making it more receptive to your developer and the rest of the chemical processes you are about to inflict upon it. :wink:

If there are more reasons, I'd like to learn them. The way it was described to me above was good enough for me, though. It made sense.

motcon · Dec 30, 2004

terri said:
I do it simply because that's the way I was taught. Supposedly it softens the film emulsion and gets it to swell, making it more receptive to your developer and the rest of the chemical processes you are about to inflict upon it.

correct. further, for shorter development times (<10 minutes or so) the pre-soak helps active developers to do their job immediately. also, if you are using one shot developers, pre-soak is recommended so you are not wasting precious time of the developer. and.....it has been said to reduce water marks on negs. i, myself, can bear witness to this, others say it isn't a problem.

sbalsama: a 10 minute pre-soak? what the...

havoc · Dec 30, 2004

Yeah you shouldn't have to presoak for more then 2 minutes.

ksmattfish · Jan 3, 2005

I presoak for about 30 sec (with agitation) with developers that recommend it (for instance Diafine doesn't use a pre-soak). Besides priming the emulsion for the developer, it's supposed to lower the chance of air bells on the film.

Kodak pre wash is usually purple, Ilford greenish, and Forte is torquoise.