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Writer / Jill Enfield

Platinum and palladium process

Always be careful when handling chemicals. Read the health and safety instructions.

Developers

• Potassium Oxalate I use as this as my developer. However, it is an anti-coagulant and a poison. Make sure that you use gloves and a well ventilated area. You can heat this developer to make warm tones (100 to 120 degrees F).
• Ammonium Citrate This will give you more neutral gray tones when used with Palladium that will make it look more similar to Platinum.
• Sodium Acetate This is more contrasty that Potassium Oxalate.
• Potassium Citrate Less contrasty than Sodium Acetate, but still more than Potassium Citrate. This is relatively non-hazardous.
• Sodium Citrate Lower contrast than Potassium Citrate and colder in tone.

Clearing baths

• EDTA (ethylene diamine tetra-acetic acid tetra-sodium salt) Hydrochloric acid
• Citric acid Hypo clearing agent (used in combination with the above)

Developer

• Distilled water (1000F) 48 oz.
• Potassium oxalate 1 lb.
• Heat the water and mix until the potassium oxalate is dissolved. This solution will keep indefinitely, in fact, some say it improves with age and never throw it out. Add fresh developer to replenish as necessary.

Clearing bath

The following mixtures are listed, but in reality you could take an 11 x 14 tray and fill it with warm water and put in a few tablespoons of any of these clearing baths, make sure they are dissolved, and they will work.

Keep in mind that the thicker the paper, the more clearing bath is needed. You can use anywhere from 1 to 5 tablespoons. The stronger the solution, the faster it will work. You should not keep your print in a strong solution for very long or it may weaken the paper fibers. You may need to experiment: every clearing bath will not work with every paper.

USE ONE OF SOLUTION 1, 2 OR 3:

Solution 1

EDTA:

• Distilled water (warm) 944 ml (1 qt)
• EDTA Tetra Sodium 2 heaping tablespoon
• Sodium Sulfite 2 heaping tablespoons.

Wear rubber gloves. Properly stored, this solution will keep indefinitely. EDTA is not an acid, therefore, it is safer to use than the hydrochloric acid listed below.

or... Solution 2

• Distilled water (1000F) 944 ml (1 qt)
• Hydrochloric acid 20 ml

Wear rubber gloves. Acids can stain and burn, even in dilute solutions. IMPORTANT: Add the acid to the water, not the water to the acid, to avoid splashes. Properly stored, this solution will keep indefinitely.

or... Solution 3

Make a 1% solution:

• Distilled water (1000F) 944 ml (1 qt)
• Citric acid 1 to 3 tablespoons

Wear rubber gloves. Properly stored, this solution will keep indefinitely. This is the safest of the 3 but may not work with every paper.

Sensitizing

Working with Senzitising Solutions

To make the sensitizer into a working solution, they will be mixed in varying ratios depending on two things: (1) the size of the negative and (2) the contrast of the negative.

Oxalic acid acts as a preservative in solutions A and B. Ferric oxalate forms the image in iron and then palladium and platinum while the potassium chlorate in B controls the contrast. By changing the proportions of A and B solutions, the contrast of the print can be determined. The C solution contains the metal salt.

Sensitizing the paper

To sensitize the paper, 22 drops of A and B combined (the proportion of which controls the contrast) and 24 drops of C (metal) are needed for an 8" x 10" coating on papers of average absorbency. In other words, the sum of the three solutions should always equal 46 drops to cover an 8 x 10. The table below lists the correct amount of drops for many other negative sizes.

Platinum and palladium solutions can be mixed together or used separately. It is a matter of choice as to which metal you use or the ratio of the two of them together. Remember that platinum is more contrasty and colder in tone than palladium. Keep the two metal solutions separate and combine them drop by drop when mixing the actual sensitizer, varying the proportion as you see fit but keeping the total number of drops constant. Remember, the two metals together should equal 24 drops for an 8 x 10, but the ratio, which determines the tone of the print, is up to you.

The amounts listed below are for a brush application. If you are using a glass rod to apply your sensitizer reduce the amount by about one print size. Example: if you have an 8 x 10 negative, try using the drop amount for the 5 x 7. You might have to play with the amounts because everybody works differently. You might need more or less than someone else making the same size print.

The paper also plays a part in the amount of chemistry you will need. A smooth, hot press paper may take a lot less chemistry then a textured, cold press paper.

Combine the 3 solutions in a plastic, ceramic or glass bowl and mix well using a glass or plastic rod. Using a glass rod to apply the emulsion on paper, you can use less chemistry (one size down) than you do with a brush.

The dry, unexposed paper will be pale yellow. Minor streaks will not show in the final image.