~~~~~~~~ Excerpt from the Guide to Platinum-Palladium Photographic Printmaking by Jeffrey D. Mathias ~~~~~~~~
No part of this document may be reproduced in whole or in part without the express written permission of the Author.
updated December 2000, note added 8/2001
 
Preparing the
Stock Solutions		 Sensitizers
Contrast Agents
Metal Salts
Developers
Clearing Agents

In order to efficiently coat and process a print, stock solutions are prepared from the bulk materials.  The information below indicates the item, the componant chemicals (listed in the order mixed), their weights or amount, and a procedure.

Water being of many qualities, the following notations have been chosen for this guide.

  • Water  =  Tap water filtered to 0.5 micron
  • H2O     =   Distilled Water (by steam distillation)
    • Note: A convenient way to view the contents of a amber bottle is with a sodium vapor
               lamp.  Hold the bottle in front of the light and the bottle will seem to be clear.

    Descriptions of the chemicals can be found in the Chapter 4, Chemicals.

           
    SENSITIZER SOLUTIONS:
    The ***** below indicates that the formula depends on the actual amount of ferric oxalate in the  sensitizer powder discussed in the section on Sensitizer Formulas, the amount of Oxalic Acid from the Oxalic Acid Concentration Study, and the amount of EDTA from the Clearing Study.
    The resulting formulas may be produced with the Sensitizer Solution Formula Calculator.  More information on how individual sensitizers effect the print can be found in the section Preparing the Coating Solution.

    Warning:  Dust may be harmfull; wear protective mask and clean up any spills.
                      Sensitizers typically have a pH of 0.1 to 0.3 and may etch the skin of unprotected
                      hands; avoid contact.

    NOTE (added 8/2001): Further study of the "bleeding" of metal during processing has indicated that too much EDTA seems the culprit.  It is now recommended that EDTA in the sensitizer be kept to a solution strength of between 0.04% and 0.1%.  The actual amount can vary with different papers, so the smallest amount of EDTA to add to the sensitizer to assist with clearing should be determined for each paper.
    Solution Chemical Componant Amount Directions
    DOP Sensitizer Ferric Oxalate ***** g  In Safe Light, Weigh out dry chemicals into 2 oz bottle, Add H2O & Shake well every 4 hours, Should be dissolved in 24-36 hours.
    Do not use until completely dissolved.
    Do NOT use high heat nor microwave solution.
      Oxalic Acid  ***** g 
      EDTA (CAS: 60-00-4) ***** g 
      H2O ***** ml 
         
           
    POP Sensitizer Ammonium Ferric Oxalate ***** g In Safe Light, Weigh out dry chemicals into 2 oz bottle, Add H2O & Shake well,
    Should sit for 24 hours before using.
    Do NOT heat nor microwave solution.
      H2O ***** ml
         
         
    CONTRAST AGENTS:
    A few on the agents are listed here.  More information on how individual contrast agents effect the print can be found in the section Preparing the Coating Solution.

    Warning:  Powder of some contrast agents may present fire hazard; store properly and clean up
                     any spills.

    		      
    Solution Chemical Componant Amount Directions
           
    Contrast Agent Potassium Chlorate   Make 15 ml of each of the solutions:
    0.125%, 0.25%, 0.50%, 1.00%, 2.00%
    with H2O in 1 oz dropper bottles.
      H2O  
         
           
    Contrast Agent Potassium Dichromate   < This is the internal control >
    Make a 2.0% solution with H2O, then Make 15 ml of each of the follow solutions with H2O in 1 oz dropper bottles:  0.125%, 0.25%, 0.50%, 1.00%, 2.00%
      H2O    
         
         
           
    Contrast Agent Potassium Dichromate   < This is the external control >
    Make a 10.0% solution with H2O, then mix with Potassium Oxalate to make these solutions in 32 oz wide mouth
    bottles: 0.20%,0.10%,0.05%,0.02%, 0.01% 
      H2O  
      Potassium Oxalate  
         
           
    Contrast Agent Ammonium Dichromate   Make a 3.0% solution with H2O, then  Make 15 ml of each of the solutions with H2O in 1 oz dropper bottles:
    0.125%, 0.25%, 0.50%, 1.00%, 2.00%, 3.00%
      H2O  
         
           
    Contrast Agent Hydrogen Peroxide (3%)   Dilute as needed immediately before using.
      H2O    
         
    METAL SALT SOLUTIONS:
    The strength of the metal salt solutions depend on the sensitizer solution used and are to be determined by using the Metal Solution Formula Calculator.  Some mixtures may be found in the section on Optimized Formulas.  More information on how individual metal salt solutions effect the print can be found in the section Preparing the Coating Solution.

    Warning:  Dust may be harmfull; wear protective mask and clean up any spills.
          Weigh out chemicals into bottle, then add H2O.
    Heat in a warm water bath (<140oF) and shake.
         
    DEVELOPERS:

    Warning:  Dust may be harmfull; wear protective mask and clean up any spills.

    		      
    Solution Chemical Componant Amount Directions
           
    Developer Potassium Oxalate 283 g Warm H2O in hot water bath, Put warm H2O into a 32 oz wide mouth bottle, Add the Potassium Oxalate, and stir, Ready to use when fully dissolved.
      H2O   30 oz
         
         
    CLEARING AGENTS:
    The agent and times for clearing should be found as necessary to pass the Clearing Test.  More information on how individual clearing agents effect the print can be found in the Clearing Study.

    Warning: The following acid strengths may etch the skin of unprotected hands; keep immersion
                     time of hands limited and rinse hands in water immediately after immersion.
    Solution Chemical Componant Amount Directions
           
    Clearing Agent Phosphoric Acid
    (ACS grade, 85%)    		 2 oz Put 3 quarts water into a gallon bottle, Into 32 oz measuring cup put 30 oz water, Add 2 oz acid to water in cup, Add contents of cup to water in gal.bottle.
      water 1 gal.
           
    Clearing Agent Muriatic Acid (20% HCl) 3 oz Put 3 quarts water into a gallon bottle, Into 32 oz measuring cup put 29 oz water, Add 3 oz acid to water in cup, Add contents of cup to water in gal.bottle.
      water 1 gal.
         
           
    Clearing Agent Citric Acid 20 g Add Citric Acid to water, stir untill mixed.
      water 1 litter  
           
    Clearing Agent EDTA(Na4) 20 g Add EDTA(Na4) to water, stir untill mixed.
      water 1 litter  
           
    Clearing Agent Sodium Sulfite 20 g Add Sodium Sulfite to water, stir untill mixed.
      water 1 litter  
           
    Clearing Agent Sprint Fixer Remover 1 part Mix as per label instructions.
      water 9 parts  
           
    Clearing Agent Sodium Bisulphate 20 g Add Sodium Bisulfate to water, stir untill mixed.
      water 1 litter  
           
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