deltaH
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Help wanted to try new photographic printing process
I have an idea for a new photographic printing process.
It is based on research I did many years ago on a class of materials called polymelaminequinones which are pitch black and very inert pigments.
They form, quite simply, by the reaction of melamine and benzoquinone, simply by heating the two in water.
Now benzoquinone in turn can be form by a light accelerated auto oxidation with air, so this should make nice, durable and simple organic prints.
Step 1: Coat good quality paper with fumed silica using a sponge roller.
Step 2: In low light or red light, dissolve 5g melamine and 20g hydroquinone in 100ml boiling water.
Step 3: While still very hot, paint on the solution using applicator sponges. Work evenly. Use a hair dryer to dry.
Step 4: Expose the print to a black and white negative under strong light for some time and while open to air. How long is required is unknown for
now.
Step 5: Thoroughly wash the print in cold water to remove hydroquinone and stop development.
Step 6: Iron the print with a hot iron to complete the condensation reactions and develop the full tone. Don't burn the paper and don.t inhale
hydroquinone fumes! Toxic!
Step 7: Wash again with water to remove hydroquinone generated by the final hot reaction.
Step 8: Frame 
Any volunteers want to help to see if this would work?
Thanks, dH
[Edited on 24-6-2016 by deltaH]
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aga
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Sounds fun !
No benzene here (yet) nor quinine so i guess i'm not able.
No carbon rods yet either ...
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deltaH
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No worries, but hydroquinone is not quinine. It's a benzene ring with two hydroxyl groups opposite to each other.
[Edited on 24-6-2016 by deltaH]
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aga
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Not got any of that either.
What can it be made from ?
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deltaH
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If you boil equimolar amounts of paracetamol and sodium hydroxide, you get the monoamine version of hydroquinone and sodium acetate. That should
substitute nicely.
[Edited on 24-6-2016 by deltaH]
[Edited on 24-6-2016 by deltaH]
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Sulaiman
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you will need a photographic negative large enoigh to make the end product large enough for framing / to be seen,
e.g. a 35 mm contact print isn't much to look at
and the resolution will not be better than the original negative.
and why introduce a toxic photographic process ?
if it is just because you can, great !
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deltaH
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I wouldn't separate out the sodium acetate, these condensation reaction ultimately that make the black stuff would be catalysed by a weak base, which
sodium acetate is.
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aga
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Someone else with a lot more experience in OC probably has all these already.
You know you can do it. You NEED to jump in now.
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deltaH
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Quote: Originally posted by Sulaiman  | you will need a photographic negative large enoigh to make the end product large enough for framing / to be seen,
e.g. a 35 mm contact print isn't much to look at
and the resolution will not be better than the original negative.
and why introduce a toxic photographic process ?
if it is just because you can, great !
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hydroquinone is not that toxic, just avoid excessive exposure, wear gloves, etc, don't inhale fumes when heating to high t, the usual precautions for
most organics. It is used in skin lightning creams, but they,re dodgy products if you ask me.
[Edited on 24-6-2016 by deltaH]
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deltaH
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For starters, I.d forgo negatives and simple expose to sunlight, then iron and see if you can make a black print. Then I.d move on to placing a cut
out masking template. Simple enough to start with.
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deltaH
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Melamine is trickier to make, I welcome some suggestions for otc routes. In principle you can substitute it with any aromatic polyamine. Any ideas?
EDIT: Kevlar fibres can be hydrolysed by boiling sodium hydroxide to yield a solution of p-diaminobenzene and sodium terephthalate, another weak
base, so that would be great to combine with the hydrolysed paracetamol solution to probably also make a similarly black pigment on development.
[Edited on 24-6-2016 by deltaH]
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j_sum1
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Hmmm.
I hane a large jar of hydroquinone and another of metol. But the latter is a monoamine.
Alas my lab is in storage boxes at the moment.
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deltaH
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Ay-yaaa, it sucks that you and aga live on different continents. I never knew about metol until now, very interesting compound,
thanks for that! I learnt something new. Hydrolysed paracetamol should make a great substitute for hydroquinone as well, more convinced of that after
reading about metol 
As for the other half, it's important that you have both an aromatic and polyamine. I don't think the mechanism for forming the black pigments would
occur if not. Melamine is ideal and I'd make some effort to either procure it or make if anyone is able to give this a go. If one does find a source
for it, it's very cheap (used to make melamine resin crockery).
I will think on it some more and dig in the literature to see if I can turn up something useful. Maybe melamine can be made from urea? I know it can
industrially, but not so sure in the amateur context. I know urea easily forms cyanuric acid, which is of no use in this case.
Nevertheless, thanks for the mention j_sum1.
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deltaH
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I wonder if you can expose a sheet of print at home by holding the photosensitive paper close to a LCD screen that displays a static imagine?
I'd stick the photosensitised paper over a sheet of thick board so that it remains flat, then mount it vertically in front of the screen with a 1mm
gap. That way fresh air can come in from below as warmed air escapes from the top. The hydroquinone does require oxygen to oxidise, after all.
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