Diluted Dektol is often used in a dillution from 1:5 to 1:10. This will
give you a continuous tone.
A positive is made first by projection from the original negative.
This positive is used to make the large negative either by projection
or contact printing.
Sometimes a print is used as the positive. It is then placed in contact
with a sheet of film to make the negative (emulsion to emulsion).
Some folks have had some success using Selectol and D-76.
Ortho-litho film may be processed under a red safe light so that it
can be developed by inspection.
Check out the "archives."
Bob Schramm
West Liberty State College