I visited the reading room of the RAF museum in Hendon last Thursday to look at their escape maps, accounts of pilots escaping from France and Denmark, and to read the training manual for forced and precautionary landings in 1942.
The silk escape maps were quite different, varying thicknesses of silk, everything from full colour printing to just black on very fine silk. The edges were not finished, most were frayed, some very evenly cut, others quite approximate. The silk in most cases was very finely woven, so that the threads formed a dense surface for the ink, and were less prone to fraying I guess. There was also a tissue paper map which showed much more sign of wear and tear than the silk maps.
I also met an 87 year old man who had been an aerial photographer during the second world war, who had come in to look at a handwritten book the he had written about aerial photography that was in the archive. I arranged to contact him and interview him sometime soon. The archive are interested in any recording or transcription I might make of an interview with him too.