In 2011, both Poland and Sweden commemorated the fact that a century ago Marie Curie had won the Nobel Prize in Chemistry, "in recognition of her services to the advancement of chemistry by the discovery of the elements radium and polodium, by the isolation of radium and the study of the nature and compounds of this remarkable element".
The joint issue consisted of a miniature sheet which included two stamps. One portrayed Marie Curie at work, which formed a part of the overall image, and the second stamp depicts the Nobel Prize medal with its portrait of Alfred Nobel and a blue blob which I presume to be radium? The combination of a Pole winning a Swede's Prize made the choice of engraver rather obvious; and so the postal authorities went for a Pole living and working in Sweden: Piotr Naszarkowski.
Accompanying the Polish issue was a lovely black print of (mainly) the engraved parts only. As always a fantastic way to enjoy the engravings, and also a way to wonder once again why the postal authorities don't seem to be able to understand that an engraving doesn't need any other printing processes and that these normally only detract from the art.
Now this wasn't the first time that Naszarkowski tackled the theme of Alfred Nobel. In 2001, the centenary of the Nobel Prize was celebrated with many stamp issues. Sweden's issue was engraved by Czeslaw Slania, but Piotr Naszarkowski engraved a beautiful, large portrait of the man, which was printed in a limited edition of 300. I have no idea whether this was a commissioned work or whether it was just a private work, but whatever the reason behind it, it's an absolutely wonderful portrait.