Just a basic question about selenium toning to compensate for difficult to print negs.. There have been a number of references to this in several recent threads.

Could anyone provide a summary of the circumstances when you'd use this? With negs that have been over-developed (or over-exposed) or under-developed (or under-exposed)? Are there any side-effects or downsides to doing it?

What would be the best techniques?

Many thanks!

-- Ed Hurst (BullMoo@hotmail.com), June 25, 2001

Answers

For correctly exposed and underdeveloped images. If your nehative shows adequate shadow detail but the highlights arenot dense enough, that's a good candidate for selenium intensification - it should yield about the same effect as an increase in paper contrast of about a grade. Selenium intensification also provides protection to the image from the harmful effects of oxidizing gases in the air. Disadvantages - I guess its kind of permanant, so if you like playing bleach-redevelopment games.... but bleach-redeveloping negatives is kind of chancy itself.... Cheers, DJ

-- N Dhananjay (ndhanu@umich.edu), June 25, 2001.

It is good to raise the zone placement of your negs a notch but if you have no detail in your shadows... your not going to have anything except a denser fog. It is almost grain free so it is alot better than silver intensifiers by a long shot which tend to get very grainy!!!! You don't want to do this on overdeveloped or overexposed by an means. If your negs are thin, make sure you pull a print and tone the print first to see if you like the look of this before you do permanent toning to the negs!

-- Scott Walton (f64sw@hotmail.com), June 25, 2001.

The technique is, as far as I know, to give the negs a bath in plain water for a minute, then in the selenium toner (diluted 1+3 or 1+4) for a couple of minutes and rinse for 10 minutes. Maybe a short HCA or Sodium sulfite bath before the rinse.

-- Patric (jenspatric@mail.bip.net), June 25, 2001.

Basically selenium treatment of negatives adds density to highlights that are too flat due to underdevelopment. It does next to nothing to shadow areas. If the negatives are underexposed, selenium will have little effect.

The procedure is to dilute selenium with water at 1:2. Immerse the negatives for 10 minutes, agitating 5 sec / 30 sec. Wash and dry negatives as usual.

You can expect to gain roughly one paper grade of contrast, with no apparent penalty. It's a highly effective treatment. I've used it a number of times with very satisfying results--even on 35mm negs. It's so good, I've even considered underdeveloping 35mm deliberately (to keep grain at a minimum), then treating with toner, since selenium does not increase apparent grain.

-- Ted Kaufman (writercrmp@aol.com), June 26, 2001.

It can also be used to increase the contrast in selected areas of a negative. You may have a shadow area that could use a boost or clouds that could use a little contrast increase. Soak for a couple of minutes and then gently paint selenium toner on the area with a very soft brush. Depending on the amount of silver there can be a 1/2 to 1 stop increase in density. James

-- james (james_mickelson@hotmail.com), June 26, 2001.