It is generally thought that the platinum palladium process may be carried out in subdued incandescent lighting.  Although this may be true sometimes, it is easy for prints to be fogged, often without the knowledge of the printer.  Due to fogging, the author switched from incandescent lamps to low wattage yellow bug lights,  and then, due to fogging again, began using a Sodium vapor lamp.  Plenty of illumination to see well and no fogging were the results.  Some sodium vapor lamps include two sets of filters (yellow and red).  Use only the yellow filters.

The most critical time for a safe light is during the coating procedure.  The mixture seems to be more light sensitive when wet.  Another time to be careful is in the developer and the first clearing bath.  It is better to curtail viewing the print until the print is fully cleared than to risk fogging it.

Any work light should be evaluated by the Fogging Test and used only if it passes.  A light is only considered "safe" when it passes the Fogging Test.

Positioning the Lamp
The most important area for bright illumination is the coating area which can also be used for weighing and mixing sensitizer solutions.  Walls and ceiling should be painted white.  The Safe Lamp should be positioned near the coating area so that the light can reflect off the ceiling and provide enough light at the coating area to clearly read a newspaper.  Some of the light will need to make its way to other parts of the work area such as the printing area and the sink area.  The illumination in these areas should be enough so as to avoid tripping on or bumping into objects and enough to identify clearing baths and such.  For large work areas, two safe lamps may be needed.

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