The Five Squid from Fourecks, that country’s first stamp, provides a shade variation in a reprint combined possibly with a different paper used. The earlier print was red on a white background, while the later print had a definite yellowness to it, both in the ink and the paper.

Looking closer reveals that the printing technique is very similar suggesting the same printing machine was used by both. The later print does show poorer colour registration with the yellow ink slightly misaligned to the magenta horizontally. But this does not explain the overall appearance differences. The paper used is slightly off white, and it is a combination of this and registration that is responsible.

Before anyone thinks that these differences may be be the result of imaging, the two paired images come from the same scan and same photograph, without any additional changes to exaggerate. There is, of course, a Sport for both colour variations.

A similar situation occurs with the Bad Blintz Three Bizot stamps issued a couple of months later. This stamp has at least three noticeable shade variations. Apart from the regular mid-crimson shade there is also a more ‘yellowed’ shade and a paler crimson resulting from a reduction of the overall background colour which can be seen on the sheets. Naturally, there are sports of each of these shades, but even I don’t go so far as seeking these out!

Additionally, two different papers have been used for these stamps, with both matt and shiny gums. The matt gummed paper may be the original and has been seen on the regular stamp and the yellowish. The shiny gummed paper has been used on the regular and pale stamp. Furthermore, the matt gummed paper seems to be slightly poorer quality because of the more ragged perforations that are found after tearing - dare I call them ‘ratty’?

      
good perfs                                                                                 ratty perfs

So the Three Bizot stamps have at least four recognisable print runs. Assuming that there would be similar size stocks of this and the Five Bizot stamps, I would assume that the latter would also have had multiple print runs. However I can only find matt gummed stamps and no shade varieties.
Did anybody else make sure they had an example of the perforated Approved by the Board label that replaced the bottom left stamp on this sheet?