Before charts, traders read "the tape" — the ticker stream of every executed trade: price, size, time. The tools changed; the skill didn't. Modern tape reading means watching the time & sales stream and its aggregations to judge who is aggressive right now — the fastest-reacting information a market produces.
Every executed trade carries four facts: price, quantity, time, and — inferred from which side of the spread it hit — the aggressor. A trade at the ask means a buyer crossed the spread (impatient); at the bid, a seller did. One print is trivia. The stream is the story: acceleration, size clustering, and one side repeatedly paying up to get filled.
Watching raw time & sales on a liquid NSE stock is drinking from a firehose — thousands of prints an hour. The modern practice keeps the skill but layers aggregation on top: the footprint is the tape organised by price, CVD is the tape summed into one running score, and big-trade markers are the tape filtered for size. Reading these together IS tape reading — just at a survivable pace.
The tape is noisier than in 1990 — algorithms slice orders and spoof intent. That is precisely why aggregations (footprint, delta, big-trade filters) replaced raw print-watching: they surface the persistent behaviour that slicing cannot fully hide.
Most broker terminals show a basic time & sales window. VolumeLens works one level up: the same stream classified by aggressor side and aggregated into footprint, CVD and big-trade markers in real time.
Persistence of one-sided aggression — a stream of trades repeatedly hitting the same side of the book while price barely rewards it. It precedes moves more reliably than any single large print.
Partially. Replaying sessions builds pattern recognition, and VolumeLens's replay mode exists for exactly that. The live component — feeling pace change in real time — only comes from watching live sessions.