Why make your own emulsion?

Ryuji,

I have never thought of the negative as anything
other than a step in a process that leads to a
final photographic image. Clearly the nature of
the negative material in terms of its contrast,
curve, sensitivity to light of different colors,
etc. can have a very important impact ion the
final image. For example, albumen prints made
from wet-plate collodion negatives have a
distinctive look that results, at least in part,
from the negative material itself.

Assuming that your interest is in a final image,
what are the distinctive characteristics of your
emulsions that give distinctive qualities to the
final image, and what are those qualities?

If your interest and joy is in emulsion making
per se my question above does not need an answer.

Sandy King

>From: John Prokos <john@prokosphoto.com>
>Subject: .AN?liquid emulsions?
>Date: Sun, 15 Feb 2004 23:01:52 +0545
>
>> Does anyone here have experience with Rockland Liquid Emulsions?
>
>I don't have experience with this product. I make my own from scratch,
>so below is based on my batches, not on that product, though my
>batches are pretty standard silver gelatin material.
>
>> Does the surface temperature you apply the emulsion to matter? I would
>> imagine it should be approximately the same as the emulsion if possible
>> rightä
>
>That is probably ideal to get most even result. If the surface is
>cooler, viscosity may go up as you work the coating.
>
>> How strongly does it adhere to the surface it is brushed onto? What
>> if the surface is not porous? Or is very porous?
>
>Paper, cloth etc. -- no problem. Suede leather -- small dripped
>emulsion sticked there without cleaning or brushing on the surface
>(though if you want to use leather, I'd clean the surface and brush.)
>
>Glass -- needs good cleaning, and I'd use surfactant (PhotoFlo, Triton
>X-100, etc.), hardener (glutaraldehyde), plasticizer (glycerol aka
>glycerin, triethylene glycol). As far as I know, Kate does this way
>except with formaldehyde. After coating, chill setting at lowest
>temperature you can get easily (but without freezing) works the best.
>I put coated glass in fridge for several minutes, then take them out
>for drying at room temperature.
>
>For paper and other absorbent material, it's ok to dilute the emulsion
>a bit. But for glass and other smooth surfaces, I'd use thickest
>possible emulsion.
>
>> Can I use a toner like Kodak Selenium Toner on the emulsion?
>
>Yes. Make sure to fix it very well, especially if your coating is
>thick.
>
>> Are there any extra materials or equipment I will need other than a brush a
>> surface and the emulsion?
>
>Anything you can use to do water jacket at 35-40C. I use a brown
>glass dish to hold emulsion, and put this in a shallow water bath on a
>heating surface, so that I can use 4-inch brush easily.
>
>--
>Ryuji Suzuki
>"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)
Received on Sun Feb 15 13:14:48 2004