metal salts

Dichromated Gelatin.
dannybee
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metal salts

Post by dannybee » Fri Jan 27, 2017 2:24 pm

I was reading old papers from the 1860 on dichromates and metal salts, that will make the sensitivity of the chrome 3x more sensitivite to light. the highest was lithium salts, it ther a way to converta bromide to a salt? :D

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admin_jsfisher
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Re: metal salts

Post by admin_jsfisher » Fri Jan 27, 2017 2:44 pm

Any mention of sodium salts? I have some sodium salts on hand already. :D

dannybee
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Re: metal salts

Post by dannybee » Fri Jan 27, 2017 4:21 pm

it a metal try it but a low amount , the best results they said was lithium, but copper will work too

pluto
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Re: metal salts

Post by pluto » Fri Mar 24, 2017 3:46 pm

what do you mean exactly by lithium and metal salts?

like lithium dichromate?

dannybee
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Re: metal salts

Post by dannybee » Tue Mar 28, 2017 1:45 pm

Lithium bromide would be a metal salt, the way I understand it :D

pluto
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Re: metal salts

Post by pluto » Tue Mar 28, 2017 11:01 pm

dannybee wrote:Lithium bromide would be a metal salt, the way I understand it :D
i think you need to explain better... i don't understand what you're saying.

can you link to the paper?

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Re: metal salts

Post by dannybee » Mon Apr 24, 2017 12:46 pm

its in a really old book "How to make old-time photos" it states
sensitivity can be increased threefold by adding , to a bichromated colloid layer, a metal salt which precipitates on contact with a chromate but not with a bichromate. In this situation, the metal salt, itself, does not contribute to the tanning action. rather, it reacts with the neutral chromate which is formed during exposure and increases the tanning. the best results have been obtained with cerium and lithium, which precipitate with chromates at ph values between 8. and 8.5

Grayham
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Re: metal salts

Post by Grayham » Tue Apr 25, 2017 3:01 pm

This is interesting, are you going to give it a try? If so please report back :)

I looked up lithium bromide and it's used in air conditioning systems. You can find it on the net for about £28 for 250g.

Grayham

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