An offset run prints each plate a run length. The run chooses which items go on which plate, how many copies of each item a plate holds (its slots), and how many sheets each plate runs, so every item gets close to its ordered quantity at the lowest cost.
The Press run card#
The Press run card sets what an offset plan works within: the most plates, the overrun and underrun caps, makeready, spoilage and costs. It shows on the Production tab when Offset is chosen in the run bar.
| Setting | API field | Default | Range | What it does |
|---|---|---|---|---|
| Max plates | max_plates | 3 | 1 to 12 | The most plates (forms) the plan may use. Every plate count up to this is planned and compared. |
| Overrun % | overrun_pct | 10 | 0 to 500 | How far above its ordered quantity an item may be produced. Empty: any. |
| Underrun % | underrun_pct | 0 | 0 to 50 | How far below its ordered quantity an item may be produced. |
| Makeready sheets | makeready_sheets | 250 | 0 to 10,000 | Sheets spent setting up each plate before good sheets. |
| Spoilage % | spoilage_pct | 0 | 0 to 50 | Extra sheets printed on top of the run and makeready, for waste. |
| Plate cost (per plate set) | plate_cost | Empty | 0 or more, or empty | The cost of making one plate set. Empty: plates are free. |
| Sheet cost (per sheet) | sheet_cost | Empty | 0 or more, or empty | The cost of one printed sheet. Empty: every sheet costs 1, so the plan with the fewest printed sheets wins. |
"Plate" here means one form with its own plate set, not the plate of one ink. Lengths don't apply: every value is a count, a percentage or a cost. The same fields are on the job in the API (see Imposition API).
How a plan is counted#
For each plate, the sheets printed are the run plus the makeready, plus spoilage on both:
printed = (run + makeready sheets) × (1 + spoilage %), rounded up
For example, a plate with a run of 1,000, 250 makeready sheets and 2 % spoilage prints 1,275 sheets.
Each item's pieces are its slots on every plate × that plate's run. They must fall between:
- at least the ordered quantity less the Underrun % (0 % by default: never fewer than ordered), and
- at most the ordered quantity plus the Overrun % (10 % by default; empty allows any overrun).
So an item of 1,000 with the defaults may be produced 1,000 to 1,100 times.
How plans are compared#
A plan is made for every plate count from 1 to Max plates. Each one is checked: every item within its caps, the totals right, and every plate a valid layout. Each plan is a row in the Report, so you can compare, say, 2 plates against 3.
A plan's cost is its printed sheets × Sheet cost (per sheet) + its plates × Plate cost (per plate set). Without costs every sheet counts 1 and plates are free, so the plan with the fewest printed sheets wins; makeready still counts for every plate. Set both costs when plates are expensive compared with paper.
More time can find a better plan, especially when the job has many items.
Reading the result#
The Production tab's Plates & impressions table lists each plate: the artworks and their slots, the run, the makeready and the sheets printed, with the plan's total. Overrun per artwork shows each item's ordered and produced pieces and its overrun: red when it is outside the caps, amber within one point of the overrun cap.
The export menu adds a Run sheet (CSV) and one PDF per plate (see Exports).
When there is no plan#
If no plan meets the caps, the run finishes with a note instead of layouts, such as "No plan within 10 % overrun on 3 plates; try 4 plates or allow more overrun." Raise Max plates, allow more overrun or some underrun, or give the run more time. An artwork that doesn't fit the sheet at any allowed angle is named in the note. See Troubleshooting runs.
Warning: Press times are estimates from your wide-format equipment
The Production tab times and prices offset and N-up sheet work with the team's printer and cutter. Until sheetfed presses and guillotines can be set up as equipment, those times come from your wide-format printer and flatbed cutter, and may not match a sheetfed press or a guillotine.