As I am right handed, I started at the right bottom of the sheet. I used Da Vinci watercolour and was surprised that the indigo turned almost black when used with few water. 
It was an interesting study to do, but I found it hard to find the ‘in between’ colours. Especially when you had to let them dry on a separate piece of paper, then I had to mix the colours again. And yes, I sometimes forgot that I was working with watercolour and the colours started to bleed into each other :o) And when lifting pigment from the paper to make the colour a bit lighter, it dried with a dark border, which gives an interesting effect.

As I bought this trio of colours last weekend it was fun to find out how they worked in relation to each other.

 

For the grey scale study I started painting at the right just like the study above, but then I remembered that I had to paint them next to the strength of the colour. I see now that the pure yellow is much darker than the watered down yellow-green. And the indigo is almost black, but I already knew that :o)

I cut a strip from my testing papers to make it possible to place the colours next to the grey scale.

Thank you Chris for this interesting study, I learned a lot!