I recently published a brief article on the hypersensitization of silver halide emulsions using a formate pre-soak., which I first mentioned in the Forum more than a decade ago. Took me all this time to try it out.
See: https://www.spiedigitallibrary.org/conf ... 6668.short
19 February 2018
Formate as a sensitivity enhancer of holographic emulsions
in SPIE Proceedings
by William Alschuler
The gain in speed is either 5xs or 10xs, depending on post-exposure processing, with no loss of resolution or diffraction efficiency.
Silver halide sensitivityy enhancer
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Re: Silver halide sensitivityy enhancer
walschuler wrote: ↑Sun Sep 15, 2019 1:49 am I recently published a brief article on the hypersensitization of silver halide emulsions using a formate pre-soak., which I first mentioned in the Forum more than a decade ago. Took me all this time to try it out.
See: https://www.spiedigitallibrary.org/conf ... 6668.short
19 February 2018
Formate as a sensitivity enhancer of holographic emulsions
in SPIE Proceedings
by William Alschuler
The gain in speed is either 5xs or 10xs, depending on post-exposure processing, with no loss of resolution or diffraction efficiency.
That sounds very impressive!
I wonder if the formate treatment works with any holographic AgX emulsion.
Re: Silver halide sensitivityy enhancer
Hi,
Do you have to sign up to this site to read the article?
Grayham
Do you have to sign up to this site to read the article?
Grayham
Re: Silver halide sensitivityy enhancer
Be a member of SPIE and/or buy a digital library subscription - aka paywall...
Re: Silver halide sensitivityy enhancer
Hi Sergio,
I sent you a PM but it's still sitting in the outbox.
Have you seen it or is this a message board problem?
Grayham
I sent you a PM but it's still sitting in the outbox.
Have you seen it or is this a message board problem?
Grayham
Re: Silver halide sensitivityy enhancer
I received it now. Will send it.
Confirm if the paper is OK
Confirm if the paper is OK
Re: Silver halide sensitivityy enhancer
Hi Sergio,
I have received the paper.
Thank you
Grayham
I have received the paper.
Thank you
Grayham
Re: Silver halide sensitivityy enhancer
This is an interesting read.
So do the formate ions bond to the AgX when the AgX is exposed to the formate or on exposure to light?
If it's on exposure to the formate then i'm guessing you could wash the plates after the formate soak in a similar way you do with ascorbic acid.
This may stop the colour shift after development if the shift is due to the extra material in the emulsion.
Are you aware of any superadditivity effects with ascorbic acid at all? May be interesting to try this.
Thank you very much for the paper, i'm going to try this out on my home made plates
Many Thanks
Grayham
So do the formate ions bond to the AgX when the AgX is exposed to the formate or on exposure to light?
If it's on exposure to the formate then i'm guessing you could wash the plates after the formate soak in a similar way you do with ascorbic acid.
This may stop the colour shift after development if the shift is due to the extra material in the emulsion.
Are you aware of any superadditivity effects with ascorbic acid at all? May be interesting to try this.
Thank you very much for the paper, i'm going to try this out on my home made plates
Many Thanks
Grayham
Re: Silver halide sensitivityy enhancer
Formate ions are inserted onto AgBr crystals on formation.The formate absorbs the hole (+) formed after photon exposure.
This electron - hole pair is formed after the sensitizing dye absorbs the photon energy and transfers it to the crystal. After "absorbing" the hole the formate forms a radical that has the capability of injecting a 2nd electron to reduce another Ag+ ion, so doubling the efficiency.
Ascorbic may even reduce the crystals forming more latent sites. I guess it may be additive, but you need to test.
See:
http://pagesperso.lcp.u-psud.fr/belloni ... es/125.pdf
This electron - hole pair is formed after the sensitizing dye absorbs the photon energy and transfers it to the crystal. After "absorbing" the hole the formate forms a radical that has the capability of injecting a 2nd electron to reduce another Ag+ ion, so doubling the efficiency.
Ascorbic may even reduce the crystals forming more latent sites. I guess it may be additive, but you need to test.
See:
http://pagesperso.lcp.u-psud.fr/belloni ... es/125.pdf