They are a pleasure to use and can produce beautiful prints but, despite assurances from the manufacturers, there is still a question mark over their long-term survival. This is not a criticism of the manufacturers. It is simply that these papers have only been around for 20 years or so, and in that time specifications have been changed several times. There is, as yet, insufficient evidence to demonstrate that this type of material will survive for 50 or 100 years, and yet many of today's photographs may be of greatly increased value in 100 years time - provided they survive. While manufacturers claim, on the basis of 'artificial ageing' tests, that resin coated papers now have a very high level of permanence and stability, it is far safer to rely on materials that have been used successfully over a long period of years.
Scientific testing is important, but the test that really counts is the test of time.
The second requirement for archival permanence is that the photograph is properly processed, fixed, washed, and dried. Adequate chemical fixing is clearly important because without it the silver compounds in the image will be unstable, and will remain sensitive to light. Washing must not be skimped because fibre-based paper absorbs large amounts of fixer, and all traces of this this must be removed if the image is to remain stable over a period of many years. Surprisingly, drying methods are also important because excessive heat may cause microscopic cracking of the paper's emulsion or supercoat. Chemical Toning To give an even greater assurance of permanence, the image should also be toned.