[Leica] Tech Pan at ASA 100

[Richard Comen <rpcomen@compuserve.com>]

There is much written lately on Tech Pan and its processing. Several years
ago I embarked on a search for a process which would let me use TP at an
ASA of 100 to 200 as I do mostly street photography and wanted to be able
to use the wonderful attributes of TP without the very slow speed of 25
which limits street shooting. I have evolved a formula which lets me use TP
at ASA 100 without any loss of the benifits of its ASA 25 rating. 



The formula for the brew is as follows:

Directions for Pota-HC110 developer for
processing Tech Pan at ASA 100:

In 300 ml hot water mix 1 tablespoon Sodium Sulfite and 1/8 teaspoon
Phenidone . I use the set of plastic measuring spoons that come in a set
for
kitchen use. In the UK spoon measurements may be different. In weight it is
22.8 Gms Sodium Sulfite and .35 Gms Phenidone. ( If it had not been for the
intransigence of King George [  1776 ] the UK and the US  would probably 
be using the same measurements today). To the above add 2 ml. HC110
syrup ( measure  with a child's medicine syringe found at any pharmacy ).
The above will develop one roll in a single roll nikkor stainless steel
tank.
                                                                           
                                                                           
                                         
                                                     2                     
                                

When mixed, add cold water to make 300 ml. Filter through coffee filter 
that 
is placed in a funnel. Cool to 69 degrees F. Use stainless nikkor tank for
one
roll only. Discard developer after one roll, ( Phenidone developer oxidizes
rapidly and should be discarded after one roll). I place tank  in a tray of
water
that is 68 degrees to keep temp constant. Develop for 6 minutes. After
filling
tank, rap tank to dislodge air bubbles, then give one gentle inversion over
and
back. Place tank in water bath. Agitation  ONLY  one gentle inversion over
and back each subsequent minute. To much agitation will cause
unacceptable contrast.  At end of 6 min., drain, use short stop, and follow
with rapid fix for aprox 2 min. Wash as usual, rinse in distilled  water
for final
rinse, then instead of foto flow, pour in rubbing alcohol ( I prefer it to
foto
flow.  It is often on special at pharmacies for 39 cents a bottle ). Let
sit in
alcohol for a minute or so, discard alcohol and hang film to dry ( no
squeegee
or sponges as that is a terrible thing  to do to wet film). Hang in dust
free
place.  ( If  I sound dogmatic at times, it is because I am dogmatic at
times ).
Because of variations of meters, camera shutters, thermometers, and other
variables, you might want to adjust your time of development slightly. 

ASA 200 can be achieved  by increasing the developing
temperature to 70 degrees F. and following the rest of
the above procedure. There will be a some loss in shadow
detail however.

I am now mixing 3000 ml  of the above  brew at once ( ten times the above
formula ) and pouring it ( filtered ) into 8 oz  amber glass bottles (
obtained from a pharmacy ) filled to the top and tightly stoppered. The
longest I have kept a bottle is 7 months and the results were consistent
with the first bottle.

If anyone is interested in further discussion, I can be reached at
rpcomen@compuserve.com