Since the engraving of this set has been done by Mr. Leon Janssens, artist proofs issued in other colors or color sets as issued can be found. Since the thematic value of the Exp 58 stamps, it is needless to say that these color proofs signed by the printer of the stamps are extremely rare and very expensive to buy.

Also interesting to know is that the original engravings of the set are exposed on the 7th floor of the HQ of the Belgian Post (when leaving the elevator at your right). They are at about 30cm width each and are the original designs. Next time, if I will have the possibility, I will make a picture of these.