1) Use an 8% solution of EDTA (80g in 1000cc). If you're using a strong paper then a weak (2%) bath of citric acid is excellent. Remember that you'll need at least three trays of clearing agent.
2) Arentz suggests using a Sodium Sulfate and EDTA mix for Potassium Oxalate but I've no experience of it. I prefer other clearing agents.
3) You need a 33% Potassium Oxalate solution (200g of Potassium Oxalate made up to 600cc). This is your base developer.
If you're using film negatives then you'll almost certainly want to use a restrainer to achieve contrast control. If you're using the A+B method then the restrainer (in this case Potassium Chlorate) is already in the Ferric Oxalate #2 solution, but you have alternatives.
I use Potassium Dichromate as a restrainer (this goes in the developer). Potassium Dichromate leaves you with much nicer highlights than you get with Potassium Chlorate. Make up a stock solution of 10% Potassium Dichromate (this stuff is nasty - read the data sheet carefully and be careful handling it) and then add between 1cc and 10cc of this to the fresh developer depending on the negative. I mix up a series of developer 'grades' each with a different amount of Potassium Dichromate.
4) Your EDTA is considered exhausted once it's gone milky - so you'll need to discard it then.
If you have three trays of EDTA you discard the first when it's exhausted and replace it with the second, replace the second with the third, and use fresh EDTA as a new third bath. By cycling your EDTA like this you make it last longer. You'll still use a lot.
You never need to throw away your developer because it doesn't get exhausted. It will evaporate and get carried into the EDTA so you'll need to top it up periodically.
5) Keep your chemicals in a safe place (e.g. a locked cupboard). Keep everything marked properly so if you ingest a powder or solution (or someone else does) then the medics know what's involved. Work with powdered chemicals in a well ventilated place (ideally a fume cupboard). Read and follow the MDS for all chemicals.
If you're using heated Potassium Oxalate then good ventilation is even more essential. You may experience headaches and flu-like symptoms if you inhale the vapours for too long (I no longer heat it except for final prints).
UV goggles are essential for the UV exposure, but not really necessary for the wet process – but if you're worried about splashes then wear goggles until you've done enough printing to make your own judgement about splash risk.
Gloves are a good idea when handling chemicals.
There's more instructions on making your first prints here: http://www.ianleake.com/platinum-pri...r-first-prints
Hope this helps.
Last edited by Ian Leake; 04-09-2012 at 12:13 AM. Click to view previous post history.
Reason: Re-wrote the stuff about restrainers