Volume Chart Notes
Volume charting is the practice of plotting how much of an instrument changed hands, interval by interval, and reading that record next to price.
Volume is the count of everything traded during one interval of a chart: shares for equities, contracts for futures, coins on crypto venues, or price updates on forex platforms that have no central tape. Plotted as a histogram under the price panel, it gives every candle a companion column of identical width and varying height.
The plotting rules are simple. One column per interval, height proportional to the amount traded, colour usually borrowed from the candle above. Nothing in the histogram is smoothed or derived; it is the rawest number on the screen after price itself.
The questions volume can answer are questions about participation. How active was this interval compared with its neighbours? Is activity expanding as the move develops, or draining away? Did the busiest trading cluster at the top of the range, the bottom, or the middle?
The questions it cannot answer are just as important. A bar does not say who traded, what they intended, or what they will do next, and the same total can represent one large order or ten thousand small ones. Volume is a census, not an interview.
Held to those limits, the number earns its panel. It turns a price chart from a line of outcomes into a record of outcomes plus attendance — and attendance, how much of the market showed up, is the one thing price alone never says.
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