What is shade variation?
Every tile has its own particular shade. The degree of shade variation indicates the level of tone evenness in a certain series and ranges from V1 (high level of evenness) to V4 (high level of unevenness.
The shade variation of a series identifies the aesthetic value of a series that derives from the original material it is created from (e.g.: nature marbles have a high level of shade variation, whereas sands are very even). It is important to note too that the tone or shade differs from production to production as it all depends on the kilns that fire the tiles at over 1200°C.