RA and SRA paper sizes: the printer's raw sheets
RA and SRA sizes are untrimmed sheets that printers cut down to finished A sizes. The best known is SRA3 at 320 × 450 mm, the standard sheet in digital printing, which holds two A4 pages with bleed and printer's marks.
Contents of this page
All RA and SRA sizes
| Number | RA | SRA | A for comparison |
|---|---|---|---|
| 0 | 860 × 1220 mm | 900 × 1280 mm | 841 × 1189 mm |
| 1 | 610 × 860 mm | 640 × 900 mm | 594 × 841 mm |
| 2 | 430 × 610 mm | 450 × 640 mm | 420 × 594 mm |
| 3 | 305 × 430 mm | 320 × 450 mm | 297 × 420 mm |
| 4 | 215 × 305 mm | 225 × 320 mm | 210 × 297 mm |
Both series are defined in ISO 217. “R” stands for raw, “S” for supplementary. RA0 has an area of about 1.05 m², SRA0 about 1.15 m², which is 5 and 15 % more than A0.
Why raw sizes exist
A press cannot print right up to the paper edge. It needs room for the grippers that hold the sheet, and the printer needs room for crop marks, registration marks and colour bars. On top of that, every design with colour to the edge is printed with bleed and trimmed afterwards.
RA sizes leave only a small margin and suit work without bleed. SRA sizes are made for designs with bleed: flyers, brochures and anything that runs colour to the edge.
SRA3 in digital printing
Most digital presses in offices and print shops take SRA3 as their largest sheet. On one sheet you get:
| Finished size with 3 mm bleed | Pieces per SRA3 sheet |
|---|---|
| A4 (216 × 303 mm) | 2 |
| A5 (154 × 216 mm) | 4 |
| A6 (111 × 154 mm) | 6 |
| DL leaflet (105 × 216 mm) | 4 |
| Business card 85 × 55 (91 × 61 mm) | 23 |
These counts assume a 5 mm margin all round and separate bleed for each piece. When the printer lays pieces out with shared cut lines, one or two more often fit. Other combinations are calculated and drawn by the imposition calculator.
And in offset printing?
Offset presses use larger sheets that are usually named in centimetres rather than by ISO 217: 50 × 70 cm, 64 × 90 cm, 70 × 100 cm or 72 × 102 cm. A 70 × 100 cm sheet is the classic 16-page signature for A4, with eight A4 pages on each side. More on digital and offset printing.
Frequently asked questions
How big is SRA3?
SRA3 measures 320 × 450 mm, slightly larger than A3 (297 × 420 mm).
How many A4 pages fit on SRA3?
Two, each with 3 mm bleed.
What is the difference between RA and SRA?
Both are raw sheets under ISO 217. SRA is larger and leaves room for bleed and printer's marks; RA only for a small trim.
What does SRA stand for?
Supplementary raw format A.