Print production calculations and costing: sheets, waste, imposition and price per 1,000
What the exam tests
Calculation questions are marked on method as much as on the number: sheets required, waste allowance, ups, paper mass and cost, machine time. Write the formula, substitute, then state the units.
Core formulas
- Copies per printed sheet = ups (pieces arranged on the sheet).
- Sheets required = (net quantity ÷ ups) × (1 + waste %). Waste is added at sheet level, not at copy level.
- Paper mass: area (m²) × grammage (g/m²) = grams per sheet; total kg = grams per sheet × sheets ÷ 1,000.
- Imposition: pages per signature = pages per sheet side × 2; a 16-page signature is 8 pages per side.
- Cost = paper + plates + make-ready time + running time, then divide by thousands of copies for a per-1,000 rate.
Worked example
12,000 eight-page A5 leaflets, 4-up on 450 × 320 mm SRA3, 130 g/m², waste 4 %.
- Layout check: A5 with bleed = 154 × 216 mm. Along 450 mm: 2 × 216 = 432 ≤ 450. Along 320 mm: 2 × 154 = 308 ≤ 320. So 4-up is possible, with 4 pages per side giving 8 pages per sheet.
- Sheets = 12,000 ÷ 4 = 3,000; with waste 3,000 × 1.04 = 3,120 sheets.
- Paper: 0.450 × 0.320 = 0.144 m²; × 130 = 18.72 g/sheet; × 3,120 = 58,406 g ≈ 58.4 kg. At €1.30/kg = €75.90.
- Plates: 8 (four colours × two sides) × €12 = €96.00.
- Press: €90/h; 0.5 h make-ready + 3,120 ÷ 6,000 sheets/h = 0.52 h → 1.02 h → €91.80.
- Total = 75.90 + 96.00 + 91.80 = €263.70 → €22.0 per 1,000.
Traps that cost marks
- Applying the waste percentage to copies instead of sheets.
- Using the net quantity for paper and then adding waste again.
- Confusing ups with pages per sheet side; they are different numbers.
- Mixing millimetres and metres in the area calculation.
- Quoting a per-1,000 price without actually dividing the total.