silver halide emulsion preparation

Silverhalide Emulsions / Chemistry.
PRATHEEP
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Joined: Mon Sep 14, 2020 6:06 am
Location: INDIA TAMILNADU COIMBATORE

silver halide emulsion preparation

Post by PRATHEEP » Fri Dec 03, 2021 8:41 am

what are the effective washing methods for 0.5 and 3 % gelatin concentrated silver halide emulsion? and also how to improve the spectral sensitivity of the silver halide emulsion for 632.8 laser?
PRATHEEP
RESEARCH SCHOLAR
KONGUNADU ARTS AND SCIENCE COLLEGE
COIMBATORE INDIA

Martin
Posts: 121
Joined: Sat Apr 04, 2015 2:36 am

Re: silver halide emulsion preparation

Post by Martin » Sun Dec 05, 2021 8:16 am

PRATHEEP wrote:
Fri Dec 03, 2021 8:41 am
what are the effective washing methods for 0.5 and 3 % gelatin concentrated silver halide emulsion? and also how to improve the spectral sensitivity of the silver halide emulsion for 632.8 laser?
In short: freezing and thawing as outlined e.g. at https://holographyforum.org/forum/downl ... hp?id=7201

PRATHEEP
Posts: 7
Joined: Mon Sep 14, 2020 6:06 am
Location: INDIA TAMILNADU COIMBATORE

Re: silver halide emulsion preparation

Post by PRATHEEP » Mon Dec 06, 2021 12:20 am

washing is done with the same , its alright now ... but the main drawback "sensitivity" is very low …. how can I improve the spectral sensitivity?
PRATHEEP
RESEARCH SCHOLAR
KONGUNADU ARTS AND SCIENCE COLLEGE
COIMBATORE INDIA

Martin
Posts: 121
Joined: Sat Apr 04, 2015 2:36 am

Re: silver halide emulsion preparation

Post by Martin » Mon Dec 06, 2021 5:28 am

PRATHEEP wrote:
Mon Dec 06, 2021 12:20 am
washing is done with the same , its alright now ... but the main drawback "sensitivity" is very low …. how can I improve the spectral sensitivity?
Again, take a look at the pdf file at: https://holographyforum.org/forum/downl ... hp?id=7201

Joe Farina
Posts: 720
Joined: Wed Jan 07, 2015 2:10 pm

Re: silver halide emulsion preparation

Post by Joe Farina » Mon Dec 06, 2021 7:13 am

I noticed an interesting thing (to me, at least) in that paper:

"Substrate preparation
Suitable glass needs to be first cleaned by ordinary household detergent. Further cleaning can be
done overnight soaking in nitric acid, or better 5 min in Cairo acid. These dangerous chemicals can be
avoided using plasma treatment. Dielectric barrier discharge is excited by pulsed high voltage on
glass surface create high reactive species from plain air, which burn every organic contamination.
Then sublayer is applied, best adhesion promotion is created by applying 0.05% of (3-
Aminopropyl)triethoxysilane in acetone. Apply by cotton swab in thin layer, less is better. After one
hour unreacted silane needs to be washed by etanol or acetone
."

That's the first time I've seen that "unreacted silane needs to be washed by ethanol or acetone." In the past, I've let the silane/solvent evaporate and dry, and left any unreacted silane in place, prior to coating the gelatin layer. I've never had any emulsion-lifting problems, so I wonder if this step is really needed. I also use the same silane for pre-treatment prior to laminating glass-to-glass using Hxtal epoxy, and so far, no problems. But now I wonder if the unreacted silane should be removed.

On the subject of cleaning/subbing glass, I stumbled across an interesting product which seems to "rock" with regards to cleaning glass: Bar Keeper's Friend. In the past, I've used TSP, but I plan to use this product, which seems to have a brutal cleaning effect on glass. It contains oxalic acid, which appears to be the key ingredient. It also contains feldspar (Mohs hardness 6, hardness of glass ~5.5), and should be used carefully on glass.

https://www.barkeepersfriend.com/oxalic ... ic-of-bkf/

jrburns47
Posts: 153
Joined: Mon Sep 14, 2015 2:48 pm
Location: Oyster Bay, NY

Re: silver halide emulsion preparation

Post by jrburns47 » Mon Dec 06, 2021 8:29 am

Joe,
I’d be interested in learning more about silane glass treatment for pre-lamination and use of hxtal and any equipment needed. Please feel free to email me.
Jody Burns


Martin
Posts: 121
Joined: Sat Apr 04, 2015 2:36 am

Re: silver halide emulsion preparation

Post by Martin » Tue Dec 07, 2021 10:55 am

I've never heard of oxalic acid in that context but would be careful handling larger quantities.

By the way, the Speedball diazo might be also a good candidate for glass subbing. You could apply it in a similar way as the traditional chrome alume subbing. SPB diazo gelatin seems to stick a lot better to glass/plastics than anything I've seen with DCG, FEG etc.

PRATHEEP
Posts: 7
Joined: Mon Sep 14, 2020 6:06 am
Location: INDIA TAMILNADU COIMBATORE

Re: silver halide characterization

Post by PRATHEEP » Sat Jun 18, 2022 2:06 am

At which stage of emulsion we would take TEM study to find grain size ??? I mean before adding of dye and hardener (jelly state)?? or after added dye and hardener (liquid state)?? or after emulsion coated on glass substrate ( before exposed)??? or after recording ???

The thing is I want to know the grain size (TEM) and (XRD) Structure details of silver halides for my studies... any suggestions??
PRATHEEP
RESEARCH SCHOLAR
KONGUNADU ARTS AND SCIENCE COLLEGE
COIMBATORE INDIA

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