What is the difference between Open Loop (Expresso) and Closed Loop (PressLink)?

What is the difference between Open Loop (Expresso) and Closed Loop (PressLink)?

Let’s begin by defining the two approaches in plain terms:

  • Open loop (or “open loop control” / “open loop color process control”): In this configuration, a measurement system is in place (for example a scanner or spectrophotometer measures the printed sheet) and the data is gathered, but the corrective actions are not automatically implemented by the press control system. The operator reviews the data, then manually adjusts ink keys or other press controls in response. In an open loop, the data flow is interrupted.
  • Closed loop (or “closed loop control” / “closed‐loop color process control”): In this scenario, the measurement system feeds directly into the press control system (ink zones, console, etc.). The workflow becomes a continuous “control circuit” whereby the system calculates corrective commands and sends them to the press either automatically or with minimal operator intervention. In essence, the color control loop is closed and ongoing.

In short: open loop = measure → operator adjust; closed loop = measure → system adjust (or operator confirm).

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