Quite a number have asked for details of the CALOTYPE process so here they
are. It is a paper based negative process as discovered by Henry Fox Talbot
in September 1840. Not much used in the USA except by the Langenheims I
believe. Paper must be free of watermarks, laid lines or anything else that
might print through to the final print. Original paper was rag/gelatin but
gelatins are never the same and it depends whether the paper was made in
the summer or winter! No wonder it does not always work.
FIRST PROCESS - TO IODISE THE PAPER. Mark one side with X and coat with
7.5% solution of silver nitrate dissolved in distilled water. NOT TAP
WATER. When nearly dry immerse completely in 5.6% solution potassium iodide
in distilled water. Leave at least two minutes to convert to silver iodide.
Paper turns yellow colour. Wash about two hours in running water. Dry. When
dry hang in strong sunlight up to two hours. Keep in archival/acid free
box. Boxes as used for normal bromide printing papers are lethal to the
chemistry! This may be carried out under normal tungsten light. The
remainder use non-actinic light - ie: with no blue.
TO SENSITISE; UNDER NON-ACTINIC LIGHT. Chemicals required. 11.4% silver
nitrate solution. UNLESS STATED ALWAYS USE DISTILLED WATER. Into 28.4 ml of
this add 5.5 ml glacial acetic acid. Called Aceto-nitrate of silver
solution. Keep in dark brown bottle. Make a saturated solution of Gallic
acid - 3,4,5 trihydroxybenzoic acid. Into 4 mls distilled water put 3 drops
gallic acid and 3 drops aceto nitrate of silver mix. Coat marked side of
iodised paper, Leave several minutes and then loosly blot with CLEAN WHITE
BLOTTING PAPER. Some operators allow paper to dry spontaneously.
TO EXPOSE; Put in camera, sensitised side facing lens. Bright day exposure
F8 around two minutes.
TO DEVELOP; 1st; equal mixture of aceto-nitrate silver soln and gallic
acid. Approx 2 ml of each will cover 1/1 plate size sheet. Brush lghtly on
to marked side of paper. there may be a feint image already. When image
appears use neat gallic acid. Repeat as necessary. Do not flood the paper.
Allow image to develop so that by transmitted light it is very contrasty.
WASH ETC; Wash in running water couple of minutes. Fix in film strength
fixer about 5 minutes. The wash couple of hours.
DRY: hang on line
WAX: when completely dry wax the negative to make translucent.
This is all condensed from my fuller notes but try it first. When I have
worked out how to send attachments and you can receive them then I can send
more details without having to re-type all the time!!
APPLICATOR; Buckle Brush. Plastics tube with cotton wool stuffed in one
end. Use clean cotton wool for every application. DON'T USE PAINT BRUSHES
ESPECIALLY WITH METAL FERRULES.
There will be many problems along the way. Please keep in contact. I am
sure you all know how to make a salt print. If not details will follow. I
am away until 27 August but keep the messages flowing in.
Paper query; This is one of the big problems. I am going to see a
specialist in London in September and will let anyone who wants to, know
the results. Two of the best I have used have been one watermarked
CLOISTERS made by Whatman and another markled STAG. Neither are still made.
There must be a suitable modern paper.
Richard Morris