Workroom Considerations

Lighting Electrical Plumbing    Sink Ventalation Ambient Control     Heating     Cooling     Dehumidifying     Humidifying

The Platinum Palladium process should be performed in a work space capable of providing for safety, control, and consistency.  It is suggested to first lay out and draw the entire work space on paper carefully considering all componants and the flow of the work.  If more than one person is to be in the workroom, ample space should be provided for an uninterrupted work flow.  It is most convenient to be able to construct the entire workspace, including walls, but in many situations the work space must be designed to fit within an existing space.  The design characteristics should include those of a standard film processing area and include the following.

Lighting - The area must be light tight but have ample light for working.  All areas should have
                   switcable bright white illumination and appropriate safelights for film used and Pt/Pd
                   materials.  Although not as sensitive as film, Pt/Pd coatings can be fogged by stray
                   light.  See the section on Safe light for the appropriate lamp to use for Pd/Pt.  The Pt/Pd
                   safelight(s) should fully illuminate all work areas.
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Electrical - All outlets should be GFI (Ground Fault Interrupt) protected.  Each work surface or
                     area should have at least four outlets, including the sink area.  Outlets should be placed
                     above the work surfaces such as with kitchen counters.  Outlets at a sink should be high
                     enough to avoid being splashed.  Two or three 20 Amp circuits should be used for the
                     outlets.  An additional two or three 20 Amp circuits should be used for ambient controls
                     and ventilation.  One 15 Amp circuit should be used for lighting.  All electrical should
                     adhere to all codes.
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Plumbing - It is recommended that water is filtered to 0.5 microns.  It is convenient to have both hot
                     and cold water and a mixing valve.   The entire drain and source lines near the sink
                     should be plastic (PVC, CPVC).  It is suggested to have several valves along the sink to
                     which tubing can be attached.  Any metal in the vicinity of the sink will likely corrode
                     (including valves).  A large plastic bucket is a must for proper dilution and disposal of
                     spent developer, clearing baths, and other solutions suitable for drain disposal after
                     neutralization and dilution.  Solvents (if ever used) should be recycled and NEVER
                     disposed of down the drain.  All acids and other suitable solutions are neutralized in the
                     bucket, diluted then disposed of down the drain.  All plumbing should adhere to all
                     codes.
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Sink - Two sinks would be ideal as Pt/Pd and film processes do not agree.  3 x 10 feet minimum
            should be the sink size considered for up to 16x20 inch prints.  If only one sink is used, it
            should be thoroughly washed when changing from film to Pt/Pd.   The sink is best if made of
            wood with an epoxy paint.  Plastic grids, as those used with fluorescent lamp housings, can
            be placed on wood bars above the sink bottom to keep the trays elevated.  Stainless steel
            should not be used and will have Pt and Pd transfer to it and may be etched by the acids and
            solutions used.
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Ventilation - Air must enter the room as well as leave the room.  The best exit location is along the
                       entire back of the sink.  In this way, fumes from processing, as processing is done in
                        the sink, will be removed by the shortest path.  The input location should be the
                        farthest from the sink and on the other side of coating and exposure areas.  Any dust
                        from coating and ozone from lamps should readily enter the path of the air flow.  This
                        will direct the design and layout of the room.  A heat exchanger built into the ventilation
                        system can dramatically save on heating and cooling costs.  Any air entering the room
                        should be filtered.  The air path in a properly designed system should enter through a
                        filter; pass through a heat exchanger; be ducted to the farthest point from the sink; be
                        cooled, heated, humidified, or dehumidified; pass through the coating area; pass
                        through the exposure area; pass over the sink; enter ducting along the back of the
                        sink; pass through the heat exchanger; be ducted to the outside away from the intake.
                        The appropriate ducts should be insulated.  It is useful to have variable speed control
                        as the airflow can be slower when it is not necessary to evacuate a lot of fumes.  This
                        will help with control of the ambient conditions.   When needed, the ventilation flow can
                        be increased.  The maximum airflow should be that necessary to keep the air quality
                        at a safe and comfortable condition.  A good design of laminar flow across the sink
                        area should allow for lower air flows.
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Ambient Control - Ambient control is a serious consideration with the Pt/Pd process.  There are
                                  certain conditions which have dramatic affects on the print.  Consistency and
                                  control can be regulated with the ambient conditions.

        Heating - Heating is primarily for the comfort of the individual.  A small ceramic space heater
                          can easily supplement what is lost by the heat exchanger.  The temperature should
                          be typically less than 70^oF.

        Cooling - High temperatures can play havoc with this process.  When using the Ammonium
                          Ferric Oxalate sensitizer (POP), it is recommended to keep the ambient temperature
                          below 70^oF.   As the temperature increases above this amount, grain in the print
                          increases.  At above 90^oF, this graininess is so profound that the image blurs and
                          becomes splotchy degrading more at higher temperature.  The ambient temperature
                          should be kept below 70^oF with Ferric Oxalate (DOP) as well.  A air conditioner
                          should be located as per the ventilation design.  An air conditioner is also important
                          as the dehumidifier can produce a good amount of heat while running.

        Dehumidifying - DOP works better at lower relative humidity (RH), the lower the better.  One
                                      cannot get the paper "bone dry" at high levels (>70%) of RH.  This most likely
                                      results in a lack of maximum density.  For DOP it is suggested to keep the RH
                                      below 40%.   With POP, the highest recommended RH is 70%.  At higher RH
                                      the probability of producing a quality print diminishes quickly.  In some
                                      climates, if one dehumidifier doesn't do the job, try two.  Remember that the
                                      outside humidity is coming in with the ventilation.

        Humidifying - With POP, the higher the RH, the cooler the color of the image.  The best way to
                                  humidify is with a sonic mister.  This can be the same mister used for
                                  humidifying the paper prior to coating.  A more constant ambient RH may be
                                  achieved by running the dehumidifier and mister at the same time.
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