TH2 Drawn with "colz" option - colors and range

I have to say thank you to aaduszki because his script solves my problem.

My question is: do you think the present ROOT behaviour (white for lower values) is the expected one? I think this is very annoying.

It is not “white” it is not painted. A detailed explanation is given here.

We end up with this behavior several years ago after long discussions with users. It was agreed that the col option should behaves as explained on this page. We will not change it !
You can always define the pad background color equal to the low level of the palette

ok, I understand there is a solution, but why can’t you add an option? “COLZALL” ?

can you send me the link of the discussion because all the program that I know like mathematica / matplolib and probably more behave exactly in the opposite way.

I think that all of this problems came from the fact that histograms are intended to store counting, so it is uselfull to have cell with 0 entries not painted (white usually). But sometimes they’re are used to show a quantity (positive or negative) along two axes.

Yes they are used for counting 99% of the time. So we keep the current behavior. Change the Pad background if you are not happy with white.