In the 1990s (and maybe still?), the philatelic bureau of the Swedish Post had this wonderful habit of sending out Christmas presents to their regular customers. These existed of special prints of engraved parts of certain stamps.
You guessed it, in 1996 the special printing focused on Sjööblom's engraving of that particular booklet. The info on the booklet says that these prints were originally made to determine the colour in which the engraved part would be printed. Eventually, the colour black was chosen.
'Normal' collectors sometimes complain that these items are a bit gimmicky, but as a collector of the engraver's art, they're anything but. In fact, they're quite magical, because it allows one to enjoy and appreciate the engravings.
I'd even go one step further and say that, even though the stamps themselves are nice as well, the engravings-only printings are much nicer.
But then, that's just me being incredibly biased!
See yous later