[pure-silver] Re: Mercury Intensifier (VMI): was Increasing Grain
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 16 Jun 2006 13:04:11 -0700
----- Original Message -----
From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, June 16, 2006 6:24 AM
Subject: [pure-silver] Re: Mercury Intensifier (VMI): was
Increasing Grain
VMI is said to increase contrast. If your negative is
already contrasty
then this intensifier may not be the best choice. If the
negative lacks
shadow detail then no amount of intensification will produce
it. Have
you tried bleaching and redeveloping in a staining
developer. From what
I have read this can be done a number of times to gain
density.
Jerry
The image from a Mercury intensifier is not permanent. I
don't know what the mechanism is but the warning is frequent
in literature describing them.
A Mercury redeveloper can be used with bleaches other
than Potassium cyanide. The amount of intensification is
less but there is better intensification of the shadows.
Monckhoven's Intensifier has the property of reducing the
shadows while intensifying the denser areas. It was really
meant for dot sharpening of half tone negatives.
There are other intensifiers which may be superior for a
weak negative. Kodak recommends its Quinone-Thiosulfate
intensifier, In-6. Kodak states that it gives the greatest
amount of intensification of any single bath intensifier.
However, the images are not permanent.
Bleach and redevelop Sepia toner will provide some
intensification, however, the negative must be well washed
since any residual hypo will form Farmer's reducer with the
bleach bath.
Kodak Chromium intensifier, In-4, produces relatively
long lived images. The bleach is a simple Dichromat bleach
but uses Hydrochloric acid rather than Sulfuric acid. This
results in generation of Silver Chloride rather than
removing the silver.
Kodak In-4 Stock Solution
Potassium Bichromate 90.0 grams
Hydrochloric acid, concentrated 64.0 ml
Water to make 1.0 liter
For use take 1 part bleach and 10 parts water.
Bleach thoroughly and wash for about 5 minutes in running
water.
Redevelop in a low sulfite developer like D-72 (Dektol)
diluted 1:3 for about 10 minutes. Carry out the
redevelopment in room light but avoid direct daylight. Wash
thoroughly after redeveloping.
The process can be repeated for greater intensification.
Intensifiers of all types increase contrast. They are
mainly useful for properly exposed but underdeveloped
negatives. Underexposed negatives will tend to have little
or no shadow detail even when intensified.
If you are interested in the Kodak Quinone-Hypo or Kodak
Silver intensifiers, and can not find them, I will post them
to the list (lots of typing).
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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