Gold Chloride "management"

I just bought 3g of gold chloride to make direct gold toner 231. Given the cost I would like to make sure I manage the product in the best possible way. So here are my three questions. I will of course keep the two stock solution apart and mix to produce the working solution as needed.
Is there a benefit from keeping the gold chloride powder in it's dry form and mix with distilled water as needed or does the gold chloride solution keep so long that there is no need to bother and I can put it all at once in solution?
Am I correct in assuming that the gold chloride solution is not susceptible to oxydation (no problem in keeping a half empty bottle...)?
Again, am I right to assume that there is no downside to go straight to a 0.25% gold chloride stock solution instead of making a 1% solution that one has to later dilute to 0.25% (PF kit comes with a 60ml 1% solution that needs to be diluted to 250ml and Tim Rudman's book repeats the same formula)?
Many thanks!

I'm unclear as to whether you have powder or a solution. What is the powder or solution currently in? Do you have three 1g containers or one 3g container?

These are three one-gram containers.

I add a very small amount of gold chloride to my recipe of platinum and palladium for printing. I buy it premixed from Bostick and Sullivan in Santa Fe, NM. I've been buying supplies from them for many years and think you can get the information you are seeking from them. The solution I get from them keeps with no problems.

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If your gold chloride came in sealed glass tubes you can keep it as a salt as long as you like. I would however mix everything that has come in contact with air, it's quite hygroscopic.

The only downside to mixing a 0.25% solution is that it's harder to mix something that calls for a 5% solution of gold chloride at a later point. Maybe mix 5% or 1% stock solution?

Diluted gold chloride keeps well, I don't think it ever goes bad.

Edit: It decomposes in light though, so store it dark.

What exactly are you planning to do with gold chloride? Toning silver papers or something else? I use a variation of GP1 gold chloride toner which uses two separate A&B liquid concentrates which are mixed together just before use, and then must be discarded at the end of each session. I buy my gold chloride in 1% bottled solution. Most published prescriptions waste gold like heck. It doesn't take much. A single little 100ml bottle of 1% gold chloride costs around $75 and lasts me an entire year or more; and I rarely print smaller than 16X20.

Beware fulminating gold, as it is prone to explosion with the slightest touch.

Photopathe said:

Is there a benefit from keeping the gold chloride powder in it's dry form and mix with distilled water as needed

Click to expand...

It takes up less space that way.
I generally dissolve my gold chloride 1 gram at a time into a 1% solution. This lasts quite a long time for me since gold toning is something I only do periodically. A 1% solution also turns out to be quite convenient given the actual amount used in practice.
In general, dry powders keep better than solutions, but gold chloride solution is also very stable in my experience. Even in a partly full bottle.

cliveh said:

Beware fulminating gold, as it is prone to explosion with the slightest touch.

Click to expand...

I am curious as to why you mention this as it has nothing, nada, nil to do with the question that was originally asked.

I essentially agree with most of what has been said...

Gold chloride stock solutions (i.e. the gold and water only) are very stable. Stored in a brown bottle, a gold chloride stock will last indefinitely.

Make the most concentrated stock that you can conveniently use. But keep in mind that if you go too concentrated, you might run into the limit of solubility for a compound. This is not likely in the current case. Also remember that it is easy to further dilute a solutionthat it too concentrated but difficult to increase the concentration of a stock that is too dilute.

By 'conveniently use' I mean allows you to measure the volumes you need with the tools you have... the more concentrated your stock, the less volume you will need and sometimes that volume can get too small for you to measure accurately.

In the case of gold chloride, I usually make a 1 or 2% stock.

If your stock is a different concentration than the one called for in you recipe, just adjust the volume you use by the ratio 9f the concentrations. For example, if the recipe calls for 1 mL of a 0.5% solution and you have a stock that is 1%, you would use 0.5 mL of the 1% stock and add an additional 0.5 mL of water to keep the volume the same. Why 0.5 mL of the stock? Well your stock is twice as concentrated as the one called for in the recipe, so you would need to use less of you stock to have the same amount of gold as the recipes stock.

This works the other way as well. For example, if you only have a 1% stock but you recipe calls for, say 2 mL of a 2% stock, you could use 4 mL of the 1% and leave out 2 mL of water. Again, why 4 mL? Because the ration of the two stock concentrations is two, but in this case your stock contains less gold per volume that the specified stock so you will need more of your stock to get the same amount of gold.

I hope that I have explained this bit of basic chemistry clearly enough to be useful.

Thanks for the input everyone!
For now I intend to use it mostly for direct gold toning of silver prints (often following thiocarbamide toning) but eventually also for some alternative processes. I was not thinking about the fact that a low 0.25% concentration could be a complication at some point with other uses so thanks! So going to mix it all at once as a 1% solution.

I bought 50ml of 1% gold chloride from Bostick and Sullivan in late 2021 when I first started getting into Kallitypes. I've been using it to mix up small, one-shot quantities to tone a single print at a time. The original plastic bottle it came in is nowhere near full anymore and far from airtight. I've just kept it in the dark, and noticed zero change in its effectiveness in the simple toner I'm using. As recently as last night I toned an 8x10 and it came out looking exactly as it should, same as when the bottle was brand new. I realize a year and change isn't exactly a torture test for the shelf life of a chemical, but I've never read of it degrading with age.