Making an RBG chart on Excel I was testing the RGB color mechanic on Excel, so I did the following:

sub paint()
red = 255
blue = 0
green = 0
Max = 48
For col = 1 To Max
    For Row = 1 To Max
        Cells(Row, col).Interior.Color = RGB(red - col * Int(256 / (Max * 2)) - Row * Int(256 / (Max * 2)), green + col * Int(256 / Max), blue + Row * Int(256 / Max))
    Next Row
Next col
end sub


This makes an RBG chart on Excel filling the interior color of every cell on a max x max square. It was just made as a test and I think it worked pretty well.

I am looking for improvement, if possible.
The expressions Int(256 / (Max * 2)) and Int(256 / Max) have constant values inside the loop. It would be good to save them in a local variable before the loop and reuse.

The line where you set the cell color is too long, I have to scroll horizontally to see what's on the right hand side of the line. You could improve that by putting the red, green, blue values in variables. I would also rename the current red, green, blue variables to redBase, greenBase, blueBase, or similar.

The naming of the loop variables Row and col are inconsistent in capitalization. It would be better if they were either both lowercase or both starting with a capital letter. Similarly, it would be better to consistently capitalize all keywords, like you did For and Next.