[pure-silver] Re: Dense Negatives
----- Original Message ----- From: <ATIPPETT@xxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, July 29, 2007 3:51 PM
Subject: [pure-silver] Dense Negatives
I have a number of negatives that are too dense due to over development. TRI-X Professional fixed with a hardener. Using Kodak's Farmer's Reducer and after seven 4 minutes baths I achieved some noticeable reduction. Am I on 
the right track here or is there a better  method?

Alan Tippett
San Jose
I
If the negatives were normally exposed and overdeveloped they will be too contrasty in addition to being too dense. Check the printing contrast before selecting a reducer. Farmer's can be used in two ways: the more common method, where the bleach and hypo are mixed together, reduces low density areas faster than high density areas, increasing contrast and clearing shadows. When the bleach and hypo are used _separately_ it tends to reduce proportionally thus reducing contrast. Kodak recommends this for overdeveloped negatives. Do it a little at a time because its hard to tell how much reduction you are getting in the bleach. Wash the negatives for a few minutes before re-treating them in the bleach part. The packaged Kodak Farmers can be used either way. After the final reduction I recommend fixing in fresh hardening fixer. Kodak has a non-packaged reducer claimed to give great reduction of contrast. I will copy the formula here for those interested. 

Kodak Persulfate Reducer R-15
Super-Proportional: For Great Reduction of Contrast

Stock Solution A
Water                                1.0 liter
Potassium Persulfate                30.0 grams

Stock Solution B
Water                              250.0 ml
Sulfuric Acid, 10% solution         15.0 ml
Water to make                      500.0 ml
To prepare a 10% solution of Sulfuric Acid take 1 part concentrated Sulfuric acid and add slowly to 9 parts of water with constant stirring.
For use: Take 2 parts of Solution A and add 1 part of Solution B. Only glass, hard rubber, or impervious and unchipped enamelware should be used to contain the reducer solution during mixing and use. Treat the negative in the Kodak Special Hardener SH-1 for 3 minutes and wash thoroughly before reduction. Immerse tin the reducer with frequent agitation and inspection (accurate control of reduction by time is not possible) and treat until the required reduction is almost attained; then remove from the solution, immerse in an acid fixing bath for a few minutes, and wash thoroughly before drying. Used solutions do not keep well and should be promptly discarded. For best keeping in storage the persulfate stock solution A should be kept away from excessive heat and light. Keeping life of the stock solution a -- about 2 months at 75F.
SH-1 is a Formaldehyde hardener. There are less toxic hardeners available but here is the formula since it is referred to above: 

Kodak Special Hardener SH-1
Water                                        500.0 ml
Formaldehyde (about 3% by solution weight.)    10.0 ml
sodium Carbonate, dessicated                   5.0 grams
Water to make                                  1.0 liter
Treat negatives in this hardener for about 3 minutes. Then rinse well. Then immerse in a fresh acid fixing bath for about 5 minutes. Then wash thoroughly before being given any further chemical treatment.
Source: _Kodak Reference Handbook_ processing section, Third (1946) edition. 

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx

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