On Mon, 2 Feb 2004 16:36:10 +0100, "Biesior" wrote:
Hi there !
I'm looking for knowledge sources on photoceremic processess. Unfortunately
I can't find it in my library, because ... I'm living in Poland and theres
no any good position.
Does anybody know where Can I find this knowledge ?
Just coat a glass plate emulsion onto the ceramic and then
cover with a lacquer.
From my site :
Encyclopedia of Photography
A New York Times Company
Arno Press, 1974
Entry: Emulsions for Development, Negative Emulsions, Pgs. 216-217
The manufacture of negative emulsions is by no means such an easy
matter as positive emulsion making, but with care slow emulsions of
very satisfactory quality can be produced. The beginner is not advised
to attempt very rapid emulsions, as they are extremely difficult.
There are two principal methods for negative emulsion making - the
acid or boiling process and the ammonia method. The former will give,
as a rule, the cleaner plate, but it is not possible to obtain so high
a speed. With care equally clean plates may be obtained by the ammonia
method and greater speed. The acid process wil be treated first.
Slow emulsion
Pot. Bromide 75g
Pot. Iodide 2.75g
Nelson's #1 Gelatin 33g
Hydrochloric acid 1cc
Distilled water 550cc
Heat to 120F (nearly 49C) and add slowly with constant stirring -
Silver nitrate 100g
Distilled water 550cc
also heated to 120F. Digest in the waterbath at boiling point for half
an hour and then add -
Hard gelatine 125g
which should have been well washed in water, soaked for a half an hour
and drained for half an hour. Cool the emulsion, and set. This should
give an emulsion of about 25 H&D.
An emulsion of about double the rappidity and giving somewhat greater
contrast can be obtained by cooling the above emulsion to 95F (35C)
and adding -
Liquor ammoniae 7.5cc
Distilled water 50cc
and stirring well for about 15 minutes, the setting and allow to stand
for 24 hours.
Rapid Emulsion
Pot. Bromide 125g
Pot. Iodide 2.5g
Hard gelatine 50g
Distilled water 500cc
Heat to 140F (60C) and add in a fine stream with constant stirring -
Silver nitrate 100g
Distilled water 350cc
also heated to 140F. Digest in a water bath at boiling point for 45
min. and then add -
Hard gelatine 50g
Distilled water 400cc
The gelatine should be well washed in two or three changes of water,
drained, and then dissolved in distilled water at 110F (43.3C). This
should give plate of from 150 to 180 H&D, which are rather soft
working but clean. Greater contrast can be obtained by adding ammonia
as suggested for the slow emulsions.
Slow Ammonia Emulsion
Amm bromide 85g
Pot. Iodide 3g
Hard gelatine 145g
Distilled water 1L
Heat to 110F (43.3C) and add with constant stirring -
Silver nitrate 100g
Liquor ammoniae(*880) q.s. (*note*, Latin, quantum sufficit)
Distilled water 300cc
at a temperature of about 70F (21C). The silver should be thoroughly
dissolved and enough ammonia added to redissolve the precipitate first
formed. The exact quantity will, of course, depend upon the strenght
of the ammonia, but 65-70cc can be added at first, and then further
additions made very cautiously, stirring well, till quite a clear
solution is formed. the termperature rises to about 90F so that it is
advisable to cool this silver solution down by standing the vessel in
cold water for a short time. As soon as the emulsion is mixed, the
vessel should be placed in cold water, running water for preference,
and the emulsion well stirred till quite thick and then put away in
cold water to set. If allowed to stand for about sixteen hours before
washing, this should give a clean working plate of about 30 to 50
H&D., which will give great contrasts and wide latitude of exposure.
Medium Rapidity
Amm. bromide 90g
Pot. iodide 2.5g
Soft gelatine 50g
Hard gelatine 50g
Distilled water 1L
Heat to 120F (nearly 49C) and add with constant stirring-
Silver nitrate 100g
Liquor ammoniae q.s.
Distilled water 300cc
at a temperature of 80F (nearly 27C). This solution should be made as
before described When mixed, the emulsion should be digested in a
water bath at a temperature of 120F for half an hour, and then -
Hard gelatine 50g
which has been wel washed but not soaked, added. Cool down gradually
and allow to stand for 16 hours before washing. This should give
plates of from 100 to 120 H&D.
Rapid Ammonium Emulsion
Amm. bromide 120g
Pot. Iodide 2.5g
Soft gelatin 50g
Hard gelatin 25g
Alcohol 100cc
Distilled water 900cc
Heat to 130F (54.4C), and add -
Silver nitrate 100g
Distilled water 300cc
Liquor ammoniae q.s.
at a temperature of 75F (nearly 24C). Digest in water bath at 120F
(nearly 49C) for 1 hour and then add-
Hard gelatine (well washed ONLY!) 75g
Cool the emulsion and pour out into flat dishes;allow t stand for 20
hours. This should give plates of from 200-225 H&D.
There are many little dodges which can be learned only by experience
and experiment, but the following hints may not be useless.
in making acid emulsions it is advisable to always run the silver into
the bromised gelatin in a fine stream with continuous stirring. In the
case of ammonia emulsions, it is not so important to add the silver in
a fine stream, but vigorous stirring should be continued all of the
time.
If regularity of results is required it is important that the water
bath should always be kept at a constant temperature, and further that
the emulsion should be stirred about every 5 minutes, otherwise the
silver bromide may settle to the bottom of the vessel and give
coarsley grain, thin working plates that are absolutely useless
period. It will be noted that distilled water is advised in all the
formula given in this article, this is important as to often ordinary
tap water is contaminated with iron and other impurities which lead to
fog or loss of sensitiveness. It is advisable to even use distilled
wate for even washing your gelatine.
Greater rapidity can always be obtained by reducing the quantitiy of
gelatine during the mixing but there is great danger of the formation
of coase grain and fog. If the gelatine is much reduced it is always
advisable to add about 10% of the total bulk of alcohol, which not
only prevents this but also obviates the occurance of dichroic fog
with the ammonia method.
Directions have always been given for setting and washing emulsions.
When the emulsion has been washed enough it should be removed from the
water and left to drain for about an hour, so as to free it from the
adherent water as much as possible. In fact, it is as well to use a
clean dry linen cloth and after the emulsion has drained, place it in
this and, collecting the whole into the form of a bag, squeeze
throughly. The emulsion is then ready for melting and coating.
A test plate should always be coated first. Melt the emulsion ina
water bath at 120F (nearly 49C), then take out a little and cool down
to 95F (35C), coat a plate and put away to dry. The bulk of the
emulsion can be rapidly cooled down again, and when set, alcohol
containing 0.1% of carbolic acid poured over the top to a depth of
about 1/2 inch, the emulsion then being put away in a dark cool place.
If it is to be used soon the alcohol may be omitted but this will keep
a stock of emulsion in good condition for a week or so.
==
And no, I haven't tried it yet !
Regards,
John S. Douglas, Photographer -
http://www.darkroompro.com
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