I tend to see a faded stamp more than a printed colour variety.One
can see a very light tinge of blue in the upper half over the band
7 c.
Putting it on my monitor and reducing the temp. of the colour the blue
pigment remnants will show up little by little by reducing the contrast.
The blue pigment is there but faded out;left the spotty remnants visible
in pic 2.If blue is in that paper the it will show up.Especialy in the
top letters


The same experiment with the 2c greyish stamp.Temp. reduction.contrast reduction.
The greyish cast still prevails.

Now reversing the process from a blue example:Colour temp. increase,Saturation increase.
I can find the same coulour as in the OP's example in the upper letters and else where.
This must be something to do with the type of pigments used.

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