So then A's logarithm is twice as big as B's logarithm. I don't see the problem here, as long as you put your zero at zero and label your axes. A grid would he

So then A's logarithm is twice as big as B's logarithm. I don't see the problem here, as long as you put your zero at zero and label your axes. A grid would help too, because logarithms are rarely perceived and the information consumer needs the warning.