Wow Leslie,
a piece of cake for those who knows how.

Thank you very much.
I guess that it is easy to number the scale as well. That would be practical if I chose to make a long scale.
While working at a painting I will have a premixed ten steps gray scale of oil paint on my palette. Now I can use the 20 steps digital scale to judge the values on the reference.
I think that I will number the digital scale like this : 1 - 1