Logarithmic price scale—also referred to as log—represents price spacing on the vertical or Y-axis dependent on the percentage of change in the underlying asset's price.

A logarithmic price scale is a type of scale used on a chart that depicts two equivalent price changes by the same vertical distance on the scale.

There is disagreement on the proper way to label logarithmic scales in charts and graphs, especially when the base is not 10. This post shows several alternative ways of labeling log scales ...