1) Preheat a waterbath for a 250 ml beaker to 41°C.
2) Weigh out all ingredients.
Salted gelatin: In a 250ml beaker.
Distilled water, refrig' temp
|Soak the gelatin in the water for about 30 minutes. After dissolving together in a separate small beaker, add
Distilled water, room temp
Potassium bromide (KBr)
Potassium iodide (KI) 1%
With slow stirring, heat the salted gelatin in the 41°C waterbath for 1/2 hour.
Ammoniacal silver*: In a 50ml beaker.
||5.5 ml *plus
*Procedure: Thoroughly dissolve the silver
nitrate in the water. Under ventilation, with a dropper add the ammonium hydroxide slowly with stirring (Add a little. Stir about 15 seconds. Repeat.) A brownish-black
silver hydroxide precipitate will form almost immediately. Continue to
add and stir until the solution starts to clear a bit. Slow down the
addition rate to a drop at a time and stir longer between additions.
When you think all the little black flecks have dissolved, add
one more drop of ammonia and stir thoroughly. It is important to
avoid excess ammonia. The total amount of added ammonia should be very
close to 6 ml.
Fill a closed stopcock buret staged to be ready to move into position over the
beaker of salted gelatin.
gelatin: In a 50ml beaker.
||Distilled water, cold
Step One: Precipitation and Ripening
Set a timer for 1 hour. Check to make sure the salted gelatin is
41°C. (Keep the waterbath temp 40-41°C thoroughout entire
'step one'.) Go to red safelight. Move the buret over the
beaker, halfway between the beaker wall and the vortex.
Begin rapid stirring in the salted gelatin and add half the silver
solution. ("Rapid" is a good vortex without excessive splashing/air incorporation.) Continue stirring 1 min. Stop stirring and ripen without stirring for 30 min. Fluff the
plain gelatin and, by hand with a clean plastic spoon, gently but thoroughly stir it into the
emulsion. Ripen without stirring an additional 15 min.
Start rapid magnetic stirring and add remaining silver solution.
Continue stirring 1 min. Finish ripening without
stirring for 15 min. Stir 1 min.
Pour the emulsion into a ziploc plastic sandwich bag in a pre-chilled
lightproof container. Refrigerate 2-4 hours.
Step Two: Emulsion Washing
Under red safelight: Noodle the cold emulsion into a cotton
jelly straining bag set in a thermos of cold water and crushed ice.
Pull the drawstring on the bag and tie tightly. Secure the thermos
lid. Tip the thermos back and forth for 5 minutes. Do this six times, decarding the wash water each
time, and then let the emulsion sit without agitation in ice water for 30 minutes.
Drain and replace the water two more times (3 total). While the noodles are still in the jelly bag
after the last washing, use the potato ricer (clean and dry) to squeeze out as much water as possible.
Then, roll the bag in a clean, dry, cold terry towel and knead for a couple of minutes
to get out more water. Open the jelly bag and sprinkle 8g dry photo gelatin
over the top of the noodles and gently stir (the handle of a plastic spoon
works well.) Don't worry about completely
mixing it in. Re-tie the jelly bag and replace it in the (cold and dry) lightproof
container. Hold under refrigeration (not freezing) for a
couple hours to several days.
Step Three: Digestion
Preheat a waterbath to 51°C.
Preheat and hold a second waterbath to coating temperature. Go to
red safelight. Empty the noodles into a 400 ml beaker, scraping the cotton bag to get as much as possible. Add 6
drops 10% KBr solution mixed with 5 ml Everclear.
Stir thoroughly into cold noodles. With several small additions with
mixing, add 6 drops Steigmann's gold sensitizer (see below) mixed
with 5 ml Everclear. Stir additional
2 min. Set the beaker in the 51°C waterbath. (Maintain 51°C throughout.) Ripen without stirring for 15 min.
[Stir 1 min. Ripen without stirring 15 min.] x 3, for a total of 1 hour.
Add finals**. Strain the emulsion into clean a 250 ml beaker. Cool
with slow, gentle stirring to coating temperature. Set beaker in a coating
temp waterbath (dry plates: 37-38°C; film: ~32.5°C).
** Finals: Dry plates: 10 ml Everclear.
Film: 1 drop Photoflo 600, 3 drops Photoflo 200.
Preparing a frugal amount of Steigmann's: Make a
1% solution of ammonium thiocyanate (2 g Amthio in 200 ml distilled water
at 52°C/125°F, cooled to room temperature). Mix 12 drops of
1% gold chloride with 5 ml of the Amthio solution. Store at room
temperature in a very small amber dropper bottle.
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