Britain Stamps - Repellex Error Or What...?

Hi guys...Take a look at these 2 British stamps...There is definitely a colour change/difference between the two...Or is this a normal thing...Took colour readings from same area as the arrows indicate...The one on the left looks to me like it has more of a reddish tinge...Any comments..?
Thanks, Robert

The two samples do show different shades, but could it be due to the cancel on the right hand clover? You might try samples from the rose on the left side as there appears to be no cancel on either rose.

Ya...took it from the pedal flower on left side of stamps.

I still see shades but now reversed, the darker shade is now of left instead of right. Density of ink?

Wert I must be going blind since all I see is this black
hole.



On the other pic I don't see any difference in colour or
intensity.


Also since these stamps where printed during the whole reign
of King George VI there are bound to be some colour variations
especially during the war years when ink for printing stamps
was scarce.

These stamps were printed via photogravure not offset/litho so I don't think repellex has anything to do with it.