Page 1 of 2

Silver halide sensitivityy enhancer

Posted: Sun Sep 15, 2019 1:49 am
by walschuler
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.

Re: Silver halide sensitivityy enhancer

Posted: Mon Sep 16, 2019 6:17 am
by Martin
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

Posted: Thu Sep 19, 2019 2:11 am
by Grayham
Hi,

Do you have to sign up to this site to read the article?

Grayham

Re: Silver halide sensitivityy enhancer

Posted: Thu Sep 19, 2019 11:45 am
by jrburns47
Be a member of SPIE and/or buy a digital library subscription - aka paywall...

Re: Silver halide sensitivityy enhancer

Posted: Thu Sep 19, 2019 1:20 pm
by Sergio
Grayham wrote: Thu Sep 19, 2019 2:11 am Hi,

Do you have to sign up to this site to read the article?

Grayham
For me would be interesting to use with pulsed laser masters but I will try to convince my Lab.

Grayham, I can send you my copy, please PM me.

Re: Silver halide sensitivityy enhancer

Posted: Sun Sep 22, 2019 9:15 am
by Grayham
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

Re: Silver halide sensitivityy enhancer

Posted: Sun Sep 22, 2019 3:49 pm
by Sergio
I received it now. Will send it.

Confirm if the paper is OK

Re: Silver halide sensitivityy enhancer

Posted: Mon Sep 23, 2019 11:43 am
by Grayham
Hi Sergio,

I have received the paper.

Thank you
Grayham

Re: Silver halide sensitivityy enhancer

Posted: Mon Sep 23, 2019 12:11 pm
by Grayham
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

Re: Silver halide sensitivityy enhancer

Posted: Mon Sep 30, 2019 1:59 pm
by Sergio
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