Platinum Formula Dilemma

[Dimestore Alchemy]

A generous soul gave me the better part of a 30 ml vial of a 5% solution of Platinum Chloride. Ordinarily I use a 20% solution of Potassium Chloroplatinite. Does anyone know how I can make use of the 5% Platinum Chloride solution for Platinum printing? I would be most appreciative.

Dimestore Alchemy

 

[JOSarff]

If your normal 20% formula uses 5 drop, the use 20 drops 0f 5%. (ratio 1drop 20%: 4 drops 5%)

You'll just have more solution to coat with.

 

[Dana Sullivan]

Platinum Chloride? Is it a reddish/orange colored liquid? If so, it's probably Chloroplatinic Acid or something similar.

Is there a chemical formula or more information on the bottle? The more info the better, since so many chemicals have similar names and synonyms.

If it's truly PtCl2 or PtCl4, there isn't much you can do with it on your end. If it's H2PtCl6 (chloroplatinic acid), you can add table salt to the solution and make Na2 platinum (sodium chloroplatinate). If it turns out that it's unusable in it's current form I would be willing to trade you for a similar amount of traditional platinum solution or Na2 Platinum, since I can always reduce it back to its metallic state and recycle it.

 

[Dimestore Alchemy]

Hi Dana:

Thanks for your response. I trust yours to be the final word on this question.

The solution was bottled by Matheson, Coleman & Bell of Norwood Ohio. It is labeled: Platinum Chloride H2PtCl6 6H2O 5% by weight. It's been around for a while but there is no sediment in the solution. The color appears to be a light amber. It does appear that there may have been some evaporation even though the cap has been on tightly and wrapped with tape. I say this because it looks like the total volume has dropped from about 2/3 to about 1/2. This is just an estimate and based on my memory from the last time I checked.

Would you advise against using the 5% Platinum Chloride as JOSarff suggests, and using Na2 Platinum or Potassium Chloroplatinate? Can you tell me how much Sodium Chloride I would need to add. I'm open to suggestions including a trade.

 

[Dana Sullivan]

The chloroplatinic acid you have now may work in a similar fashion to Na2 platinum, but I haven't done enough testing for a good comparison. If you have 30ml of 5% solution, it will take about .4 grams of table salt to convert it to Na2. I would add atleast .5 g just to make sure it all gets converted, and to account for any evaporation that may have occured over time. If you don't have a scale, about 1/8 teaspoon would suffice.

Shake it up until the salt is disolved, and enjoy.

I'd say try it out, and if it doesn't work, send it in and I'll send out fresh solution or powder to you.

 

[Dimestore Alchemy]

Thanks Dana. Will do. I'll let you know how it turns out. Will I need to increase the number of drops to compensate for the dilution?

Thanks again.

 

[Dana Sullivan]

It depends. For 4x5s and 5x7s I like to use a 5% Na2 solution because it makes fine tuning much easier than using the full strength 20% formula. Come to think of it, since it's a 5% solution of H2PtCl6, by adding the sodium chloride to make Na2PtCl6, you're actually making around a 6-7% solution of Na2 (too worn out from biking with the kid to do the hard math).

In the end it really comes down to your negatives. If you're using pyro developed negs, I could see you using 2-3 drops of the 6-7% solution in an 8x10, which shouldn't throw a wrench into your drop schedule. On the other hand, if you're using 8x10 negs originally shot for silver, you might be adding 8-10 drops or more per print, which ends up being a lot more liquid to deal with.

If you think the bottle has lost volume, you may be closer to a 10% solution of Na2. Just try it out and see what happens.

 

[photomc]

If the OP is making platinum prints, what does using Na2 add to the process? Have used Na2 with palladium, but not with platinum.