[pure-silver]: Historical tidbits

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From: Garry Lewis (glewis@ftw.nrcs.usda.gov)
Date: 07/24/03-06:22:32 AM Z


>From the "Agfa Book of Photographic Formulae;1910"--

"As "Agfa" -Rodinal contains only traces of carbonic alkalies, the use of
distilled water for dilution is not necessary....

In addition to neutral sulfite and water "Agfa"-Rodinal contains only an
alkaline salt of Paramidophenol, but no excess of caustic alkali.

The most advantageous temperature for the developing solution is 15 degrees
C. (equal to 59 degrees F.)

Negatives developed in Rodinal seem to lose density in the fixing bath. It
is therefore necessary to carry development a little further than is
required.

>From Camerette #79; 1949---
The Silver Etch Process-

A silver etching is an etched chlorobromide or bromide print. The print is
made through an etching of textured screen with an exposure of two to five
times normal. Develop in a regular paper developer for two to four times
normal development. Remove print from developer and place it in the etch
solution and turn the light on Experience will tell when to remove it. After
etching wash in running water and place in fresh fixing bath.
After etching fix, wash and dry in the usual manner.

(formulas given upon request from this poster) }:^)

>From the "Hammer's Little Book; a Short Talk on Negative Making" ;eighth
edition; date unknown--

Hammer X-ray Plates-

If the tube is 10 to 12 inches above the subject, the usual outfit will
require about the following exposure:

the wrist........................15 to 20 seconds
elbow ...........................1 minute
Knee and shoulder ......3 minutes
chest .............................5 minutes
Pelvis ...........................5 to 10 minutes.
Doubling these will not overexpose your plate, but doubling again will
overexpose same.

{not to mention the patient. Wonder how many patients got radiation
poisoning?}

                                yours how times have changed, }:^)>

                                                Garry D. Lewis

"I think their all potty"

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