Question about colz option

I’m using a TH2F
histogram with the option colz I was wondering when I use this option is there a sepatate entry for 0
or just 0 is combined with low occupancy bin? If 0 is combined with low occupancy bin how can i set a separate entry for 0? Thanks a lot

The empty bin (content = 0) are not drawn by default.
If you put the option “0” in addition to COL they are drawn.
All details are explained here:
It is true that if your palette starts with a color close to the pad background color , it will be hard to see the difference between an empty bin and a low contain bin.