Younger readers can Google Letratone, the rest of you may remember fiddly scalpel work and just how hard it was to pattern a drawing!
Here is a link to a cell library containing percentage dot screens that could be useful for giving a different 'old school' character to shaded areas. They will be quite efficient in 2D DGN vector graphics but will probably create massive numbers of elements if exported to other formats so use with that in mind.
Scale as required when placing, the cells are drawn at 1mm in size to make the maths easy.
