Mixing greys - anachromatic scale

For this exercise I was required to mix black pigment with white and work in a sequence from pure white through the greys to pure black. I used Titanium White and Ivory Black WM Oil on Winton oilpaper, and being very careful to do the exercise I managed to achieve a sequence of 22 colours

Strips number 11 and 12 had only very subtle differences and I chose strip 12 as my neutral grey, and when I put my neutral grey at the ends of the sequence, beside the lightest and the darkest colours in my scale it didn’t appear to change, they look the same to me. I then compared my neutral grey to the Neutral Grey in Amsterdam acrylic and was very pleased to find that it was very close.