I'm still digesting haggis and the effects of a few wee drams, but from what I've deduced from reading wikipedia, this is a 'hand coloured' engraved version of the Alexander Nasmyth 1787 portrait, originally published the book "Portrait Gallery of Eminent Men and Women in Europe and America" published in 1873 by Evert A. Duyckinick.

Here's a link to an image of the engraved version on Wikipedia:
https://commons.wikimedia.org/wiki/F...rt_Burns_1.jpg

For interest here's a link to the highly talented graphic illustrator Noli Novak, who creates modern day portraits using an engraved style: http://www.hedcut.com/

I've spent many a happy hour using Xara PGD trying to recreate this kind of style (the pigs below), but recently have also had some quite good progress using brushes in Affinity Designer (divers helmet).

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