Logarithmic price scales are a valuable tool for investors and traders looking at long-term market trends. They are used to reveal percentage changes in price, as opposed to linear price scales which report dollar changes in prices.

A logarithmic price scale is plotted such that each unit increase in price is represented by a specific vertical movement on the graph. For example, if the stock of a company doubled in price, the same vertical movement would represent the same amount of price increase. Conversely, if the same stock only increased by 10%, the representation on the chart would be just a tenth of that of the doubling mentioned before.

This type of scale allows for more accurately detecting trend changes and meaningful patterns in stock prices. It also reveals the magnitude of market moves more easily. As a result, it is helpful in gauging market volatility. For example, a sharp increase in the stock of a company on a linear graph may be hard to detect, but would be more prominently displayed on a logarithmic chart.

Logarithmic price scales are especially useful in setting targets in long-term analysis. It allows investors to visualize the percentage growth they may expect from their investments and provides them with a comparative measure to determine if a stock is moving at a faster or slower rate than the market.

The use of logarithmic price scales is becoming increasingly popular due to their ability to keep changes in perspective over a long period of time. They are highly recommended for traders who are looking to capture trends in the market, especially if the stock has had large price increases or drops recently.