To do palladium printing, you need the following:
1. Ferric oxylate. This is the light-sensitive component of the sensitizer solution. Be aware that Ferric Oxylate has a fairly short shelf life - B&S suggest that it will last 6 months although I just finished a bottle that lasted 11. So you want to coordinate the amount you purchase with the rate at which you expect to use it.
2. Metal salts - either Pt, Pd or both. Both are expensive, although Pd is less expensive than Pt. The good news is that it lasts forever - B&S assign a shelf life of 50 years. Most Pt/Pd printers use mostly Pd with a little Pt added to cool the warmer natural tonality of pure Pd. Incidentally, a 4x5 print requires 6 drops of metal salts, so the 100ml quantity offered by B&S is enough to make a lot of prints!
3. Contrasting agent. Here's where you need to make a major decision as there are two fundamentally different approaches. The "traditional" approach used a variation of Ferric Oxylate as a contrasting agent. This works reasonably well and also allows the use of both Pd and Pt as metal salts to fine tune the image color. An approach that provides better (more responsive) contrast control is the so-called NA2 method that uses a sodium-platinum solution. With this method, the only metal salt used is Pd. B&S supply this either as a dry compound or as a 20% solution - buying the solution is more convenient, but in use you actually need a variety of solutions - 10% and 5% in addition to 20%. You can make these up from the 20% solution by diluting it further in distilled water.
4. Developer - there are a variety of developers that are commonly used in Pt/Pd printing. Ammonium citrate is inexpensive and produces neutral tone prints. Other developers produce warmer tones. Developers do not deteriorate with age and can be used forever. However, you will gradually deplete your developer because it soaks into prints and is carried over into the next processing step, so you will eventually have to replenish your supply.
5. Clearing agent - there are a number of chemicals that can be used to clear prints. Ordinary hypoclear is one option. EDTA is a very effective clearing agent that also happens to be very safe (it is also used as a food additive).
I suggest that you give serious consideration to purchasing one of the B&S starter kits rather than buying individual chemicals. They come with all the chemicals you need in quantities that are essentially coordinated. For example, the combo Pt/Pd kit has everything you need to produce 80-100 4x5 prints by the traditional process.
6. You will also need some means of coating your paper. The two accepted processes are brush and coating rod - I prefer the coating rod (it produces a smoother coating and helps conserve expensive chemicals), but I also use a brush to finish off the process by smoothing out the residual puddle left by the coating rod. The ideal brush is a watercolor "wash brush" at least 1" wide. B&S can sell you a coating rod (they call it a 'puddle pusher'), or you can make your own by gluing a handle to a short length of glass or plexiglass rod. I suggest buying one, but remember that glass will wear out the first time you drop it on the floor, so take a good look at it so that you know how to make a replacement.
7. You will need a collection of eye droppers. Chemicals are measured using calibrated droppers. Glass droppers are not scientifically precise, and calibrated droppers are always made of plastic . B&S supply a standard dropper with each bottle of sensitizing chemical in their starter kits, and you can also purchase spare droppers and bottles.
8. You will need a container to mix your sensitizing solution. A shot glass is ideal. You can buy shot glasses at any kitchen supply shop for a few dollars. I bought mine for ten cents at a garage sale. (If you have an Ikea near you, look there - their prices for shot glasses are much lower than most kitchen supply stores.)
9. You will need paper for sensitizing. B&S has a pretty good selection to choose from - be aware that there is a difference between "white" and "ecru" - the latter is distinctly warmer and in my opinion is not ideal for every subject. Papers need to be made from 100% cotton fiber and heavy enough to withstand soaking in water for an hour or more without falling apart. You can also buy various papers at art supply stores. Not all art papers work well for Pt/Pd printing - traditional favorites include Bergger's COT320, Crane's 90# cover (aka Platinotype), Crane's 32# 'Kid Finish' writing paper, Weston Parchment (this is an ecru paper), Rising Stonehenge (if you can get it - the mill is closing this month), Arches Platine, etc. In general, lighter weight papers are fine for smaller prints, but you want the mechanical strength of heavier papers if you are making larger prints.
10. Either a printing frame, or on a temporary basis, a couple of sheets of glass, one as a carrier for the sensitized paper and the other to hold the negative down while exposing it. You can take that one step further by simply taping the two sheets of glass together (duct tape works well) to make a crude printing frame.
12. UV light source. One option is the sun, but given the cost of materials, something that is more reliable is preferred. You can make up a crude UV light source using black lights from Home Depot or Lowes. Folks who do Pt/Pd printing seriously cobble together UV boxes consisting of banks of UV bulbs (either black light tubes or compact spirals, or "actinic" tubes) with provisions to shield their eyes and workspace from UV light spillage that can damage your cornea (UV light is a cause of cataracts) or fog sensitized paper.
12. Incidentals - in addition to the mandatory supplies, things that are helpful include:
- a sheet of clear acetate to place between your negative and the sensitized paper to prevent damaging the negative if the paper is not totally dry.
- a hair dryer to dry the sensitized paper
- tape - to tape the negative to the acetate sheet. 3M removable "Scotch" tape works well.
- tape to tape the sheet down while coating it. Ordinary blue painters tape is probably ideal.
- a timer that can be adjusted in the range 60 seconds up to perhaps 15 minutes (Pt/Pd printing is very slow).
- trays, drying screens, rubber gloves (it's very easy to tear wet paper, and using your fingers rather than tongs provides more control)
