Photography - DOUBLE TONING (Dual Sepia) from 1939

April 28, 2007, from Lloyd Erlick,

I've been looking at my stash of boxed up old
books ... (no guarantees that this formula
works on current materials, or ever did, for
that matter) ...

[from "Fortunes in Formulas" by Hiscox and
Sloane, Norman Henley Publishing, 1937-1939.]

DOUBLE TONING (Dual Sepia):

Here is a toner that will give two shades of
different browns in the one picture, and the
effect is very pleasing.

Make a solution of one-half ounce chromic
acid in 10 ounces water. Place the print in
this solution until it nearly fades out
(about a minute or so). Wash the print in
running water and then place the print in
ordinary film developer (M.Q.) and redevelop
back to visibility.

This formula takes the place of the old time
sulphide print for rich browns. Unlike the
old time sulphide process the above is
odorless and less liable to produce insoluble
stains.