fix and brom water

[Jeremy Lynch]

Looked through the resource pages and I am confused about fixing. 14.5 grams of thiosulfate with 100ml of distilled water? Also I just found some Brom water that is 47per cent, how does one mix with silca gel, at what ratio?

Thanks for the help,

Jeremy Lynch from Berlin, also Gold Chloride 3 is costing me 140 Euro a gram, crazy any alternatives.

[photolytic]

Some instructions in the resources section are varied and contradictory.

It appears you have misplaced the decimal point in your information.

Irving Pobboravsky recommends 15 grams of thiosulfate and 15 grams of sodium sulfite per liter.

The maximum solubility of bromine in water is 4.17 percent. (Not 47%).

Bromine to be mixed with silca gel or calcium hydroxide must be the dry type.

Once bromine is dissolved in water you can dilute it with more water for fuming.

You may find Gold chloride is available on EBay for less than 150 euros/gram.

Don’t gild every image you make. Only your best Dags deserve this final finishing step.

Gilding a whole plate requires less than 0.1gram of gold chloride or 15 euros worth.

[CasedImage]

As a community website we welcome input from all, espicially experienced practioners. Our aim from the beggining was to avoid the example of newdags.com which was static, limited and non inclusive. If you see an error or information that is wrong it would be helpful to point it out to us, as we are looking to collate and grow the resources not dictate them. Its a large site so you need to be specific about where an error is – a url address and description.

I can’t see any reference in the resources section to a fixer formula but the wiki does have a page which iterates Irv’s formula.

Bear in mind the wiki is open to editing to anyone who signs up, its our hope that people will contribute.

www.CasedImage.com

[Mike Robinson]

Hi all, Here is my advise for making “Robinson’s Quick”

 

Dry bromine isn’t quite right. Bromine is a very nasty liquid. To charge silica gel I place a SMALL open bottle of bromine in a glass jar containing the silica gel. This is also placed in a larger jar with a ground glass lid. This is placed in my fume hood. You can see the red bromine vapour being absorbed by the silica gel. Once it is deep orange/red you can cap the bromine bottle and remove it. (I acutally keep my bromine in silica gel as the seal on the bottle tends to leak and its an easy way to make charged silica. Have an open beaker of ammonia next to the charging jar when you remove the ground glass cover. It will instantly neutralize the bromine vapour that escapes. Of course the fume hood is running.

The second pic is the color of the stock (dark orange) vs working strength silica gel (yellow) When the bromine of silica gets weak, simply sprinkle a teaspoon of stock onto the stuff in your box.

 

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[jgmotamedi]

As photolytic wrote, you probably can’t mix saturated bromine water with silca gel or calcium hydroxide, but you can dilute it further (old manuals usually suggest 1:100) to make a bromine water quick.

[Jeremy Lynch]

Thank you for the fix ratios and also for the bromine water 1 to 100 ratio. Also Robinsons Quick is definitely the route I will pursue.

Again THANK YOU

Cheers Jeremy Lynch

[newone2010]

Hi all,

I never use silica mixed with I and Br.I just put I and Br into the fuming box directly before.I want to try silica method.I already bought some silica gel.

What are the virtues?Is this Silica method much more better?Fuming time quicker? less moisture?

Mike posted how to mix silica with Br,how about I?Just put I into silica and shake in a bottle?

looking forward for your reply,

Li

[photolytic]

Mike may be able to share some advantages of mixing the Iodine with silica gel but outside of keeping the moisture level lower in your fuming box I can’t name any. Fuming time will be longer. I’ve had my iodine crystals in the fuming box for 12 years and they still work great.

Unlike bromine liquid which is “anhydrous” (is that ok Josiah?); iodine won’t mix immediately with silica gel. You will have to wait until the solid crystals sublime so that the iodine vapor can penetrate the silica gel.

[Mike Robinson]

I combine about 50 grams of Iodine solid with about 200 grams of silica gel. (your box size will determine how much you need) The silica gel is about an inch deep in my box.

Besides moisture absorption, for me the gel promotes more uniform sensitizing. It also slows down the rate of sensitizing, which I find an advantage.

That being said, If you are getting good results without silica gel, why change.

[newone2010]

Thank you Mike and John!I’d like to try mix Br with silica to see what’s the different in the finall results.

[daniel]

I have a question for Mike- I took the your workshop at GEH early last year and you recommended the using the 6-16 mesh silica gel. I was wondering why you settled on the the 6-16 mesh size as opposed to any other size. Would it be OK to use a any other mesh size and if so what are the alternative mesh sizes that might still work. Also, is the indicating type of silica not suitable for charging with bromine. I finally have some bromine on the way so I would like to get some silica before it arrives in a month or so.

Thanks,

Dan

[Mike Robinson]

Hi Dan,

6 / 16 is a good size to manage when you need to remove the sensitizer from the box for transport. I cannot imagine why alternate mesh sizes won’t work.

I’m not sure what the active ingredient in indicator silica gel is and have no experience with it so I hesitate to offer an opinion on that.

best

Mike

[photolytic]

Hi Dan and Mike,

The most common moisture indicator in silica gel is cobalt chloride, It is pink or purple in the hydrated form and blue in the dry form. It is possible that the pink color might make it more difficult to judge the level or halogen added from the color of the mixture but this would only occur in the presence of moisture, an unlikely event unless one added bromine water instead of anhydrous bromine liquid. While cobalt salts are carcinogenic when inhaled, the level used here is so low that the indicator silica gel does not have to be labeled carcinogenic even in California. Since chlorine is a stronger oxidizing agent that bromine or iodine there is no possibility that chlorine would be released if these halogens were mixed with indicator silica gel.

Best, John

[Author]

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