Colour differences: Sun damage, empty ink supply or normal variation?

[xara]

Hi! I got two Mews from the XY era. One of the cards (Black Star Promo) is very saturated and has a dark purple colour and dark yellow border. The other Mew (Fates Collide) has a lighter purple background and a very light yellow border.

Is the lighter Mew sun damaged? Or is this an error and the print was made without enough ink? Or is this normal and within the normal colour variation of cards?

[Dyl]

In my estimation, this is normal variation. I would also try to compare cards from the same set. Sets (or promos) will have different saturation levels.