Information on period pilot maps

[winny]

British Escape maps were originally printed on silk (that was deemed unfit for parachutes) as silk became rarer they later printed them on Rayon.

They used pectin mixed with the ink which stopped bleed.

They also printed some on tissue.

Here's an early bartholomew Map



Got most of the info from here

The actual pilot's map was usually printed on heat treated paper but this varied from country to country.