Albane wrote:
> Please, could someone help in this ?
> Thanks.
I'm sure it's partly an issue with language -- your English is a lot=20
better than my French, but what you write below still isn't what I'd=20
call fluent. In any case, the brown liquid and green-gray powder you=20
write about are completely unknown to me -- are you talking about lith=20
printing with photographic materials, or photolithography as the term is =
used in printing books and magazines? The press industry (books,=20
magazines, etc.) uses a lot of chemicals that are completely unsuitable=20
for even alternate processes in photography (like lith printing) because =
they're formulated to work with lithographic films, which are also=20
generally unsuited to pictorial images (though there are techniques for=20
rendering either half tones or continuous tones with litho films).
If you're trying to get the runaway development and time controlled=20
contrast characteristic of certain papers in "lith" developers with=20
photographic images, you need to start with the right papers and then=20
use the right developers, but none of it resembles what you describe=20
below, as far as I'm aware.
> ----------------------------
>=20
> Albane a =E9crit :
>=20
>> Hello,
>>
>> I participated to a workshop on photo-lithography and I would like to
>> identify some of the products we used in order to buy them and go ahea=
d.
>> Could it be possible for you to give me some information or help or
>> addresses to find the accurate information?
>> With many thanks,
>> Albane
>> ------------
>> Theme : identification of chemical products for graphic arts,=20
>> photography, lithography, and alternative techniques.
>>
>> Description of the quiz I have to solve:
>>
>> Papers have already been impressed (they contain the latent image and =
>> are steel white). We work with a very few daylight. The room must be=20
>> dark but not completely. There is no artificial lighting.
>>
>> 1. Papers are imbibed with a mix of two products:
>> One is brown liquid with a medium smell, I think often used in=20
>> photography.
>> The second one is transparent like water but is very odorous (when you=
>> smell it, it is very aggressive). That looks like ammoniac very
>> concentrated.
>> When imbibed with this mix, in the darkroom, the prints become black=20
>> (like dirty).
>> According to you, what are these two products?
>>
>> 2. In order to clean this black veil, a green-grey coloured powder is
>> then used. The dry prints are put into this powder and have to stay so=
me
>> hours, still in dark. When withdrawn, this powder has changed colour a=
nd
>> is now brown clear (as if it had absorbed the first brown product used=
).
>> Apparently, this powder is an instable product.
>> This powder is then introduced into water and mixed: water becomes lig=
ht
>> blue and makes a soapy water with moss. Prints are now introduced in=20
>> this bath and have to stay some 2 or 3 minutes, agitated moderately.=20
>> When withdrawn, prints have now a visible image, covered with a=20
>> blue-grey veil.
>> According to your experience, what could be this product?
>>
>> 3. We end using a transparent liquid (sometimes it is crystals like=20
>> clear brown sugar which is melted to water and becomes transparent=20
>> liquid) put on the prints. Immediately, prints become clear pictures=20
>> with all details and colours. Then, we dry. Pictures are ready.
>> According to your experience, what could be this last product?
>>
>> I have to identify and find the chemical name of these four products=20
>> and I would be grateful to you if you could help me.
>>
>> Thanking you for your attention and help,
>> With best regards.
>>
>> Albane
--=20
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