Serious photographic printmakers have kept the platinum process alive in spite of the absence of pre-coated papers, (the notable exception being the the Palladium Co.) because of platinums' unique qualities. First is the inertness of the platinum family of metals; platinum, palladium, iridium, rhodium, and osmium. These metals (long referred to as noble metals) resist combining with other chemicals (unlike silver) making prints made from them very stable. A platinum print will remain unchanged as long as the paper it is printed on exists. We have examples of papers existing today that were made over 2,000 years ago, and we know a lot more today about making paper as far as permanence is concerned. This puts the life expectancy of a well made, well cared for platinum print on today's papers as essentially archival. We can't know really what an original Michaelangelo painting looked like because of deterioration of the colors and varnishes from age -- and that was not that long ago.

Platinum prints look different than any other photographic print. The response to light by the platinum emulsion is much more linear than that of silver, resulting in more even spacing of tones in the shadows and highlights. This makes the prints appear more luminous, more expansive, in spite of their tonal range being shorter -- blacks not as deep and whites not as bright as a glossy silver print due only to the matte surface of the platinum print. Because the liquid platinum emulsion is brushed directly onto the paper and sinks in, rather than being held captive in a thin layer of gelatin on top of the paper, the image itself has physical depth, creating a three-dimensional quality to the print. The print color is influenced by the proportion of metals in the emulsion (Platinum/cool; Palladium/warm), the composition and temperature of the developer, and the paper color and its sizing. It can range from a steel grey to a sepia brown. Then they can be toned. The finest platinum prints appear to have light emanating from within rather than light reflecting off of them.

Before discussing the mechanics of making a platinum print, let us examine the materials involved in its production. The platinum print belongs to the family of iron processes, where iron is the light sensitive agent and the platinum is along for the ride, until development. Other processes in this family include the Cyanotype and the Kallitype. Iron salt is the most common ferric oxalate, and is the one used in platinum printing. Upon exposure to ultraviolet light, it decomposes to ferrous oxalate, as suggested by the following equation:
Fe2(C2O4)3+ light(UV) -- 2FeC2O4+2CO2 (gas)

The faint provisional image that is formed after exposure is composed of ferrous oxalate which undergoes a color change to brown, from the green color of the unreduced ferric oxalate.