A0, A1, A2 and A3 Printing in London

The A series, and why the size is the specification

Large format printing is sheet work above A3: plans, drawings, posters and presentation graphics printed on a roll-fed machine rather than an office copier. Most people arrive knowing the size and nothing else — "I need an A1" — and that is a perfectly good place to start, because in this product the size really does drive the specification: what it is read from, how far away, and whether it lives on a wall, a plan table or a fence.

The A series is built on one relationship: every size is half the one above, and the proportion never changes. All A sizes share a 1:1.414 ratio, so folding a sheet in half gives you the next size down with the same shape. A0 is a square metre of paper; A1 is half of it; A2 half of that; A3 half again. This is why a drawing set up for A1 reduces cleanly onto A3 for a meeting copy without redrawing or re-scaling anything — and it is why the "scale bar" on a drawing matters more than the sheet size printed on it.

Who orders this: architects, engineers and contractors — plan sets, elevations and services drawings, printed the day they are issued; universities and researchers — A0 conference posters, usually the night before a flight; agencies and retailers — display and window posters; and anyone in a planning process, where a submission set has to be on paper, at the right size, by a date that is not moving.

A0 printing — 841 × 1189 mm

A0 is the biggest standard sheet in the series and a full square metre of paper. It exists because some drawings simply cannot be read smaller: a master site plan, a services layout with four disciplines overlaid, or a research poster carrying charts that a conference audience reads from two metres back.

For drawings, A0 goes on matt stock. Fine line work stays crisp, there is no glare under a site light, and the surface takes a pencil, a highlighter and a marker — which matters, because an A0 plan on a table exists to be written on. For research and display posters, photo satin is the choice: deeper blacks, better photographic detail and no reflection under exhibition lighting.

Resolution is the thing that catches people out at this size. Vector linework is scale-free and prints sharp at any size, but photographs and scans need 150 dpi at the finished 841 × 1189 mm to look right. A0 prints leave rolled in a tube as standard; ask if you want them flat.

A1 printing — 594 × 841 mm

A1 is the working size of the construction industry: big enough to carry a full drawing at a usable scale, small enough to open on a plan table in a site hut without knocking over the tea. Half of A0, double A2, and the sheet most planning sets and issued drawing packs arrive on.

Two practical A1 specifications come up constantly. Folded to A4 with the title block facing out: a whole drawing pack drops into a lever-arch file and the right sheet can be found without unfolding six others. And tear-proof stock instead of paper when the drawing is going somewhere wet or muddy — it does not pulp, it wipes clean, and it survives being consulted in the rain.

A1 is also the standard poster size for pavement signs, snap frames and easels. Same sheet, different stock: photo satin rather than matt, because a poster is read for impact and a drawing is read for information. If the poster is the whole job rather than part of a print run, our poster printing page covers finishes in more detail.

A2 printing — 420 × 594 mm

A2 is the size that fits where A1 is too much: a shop window, a framed notice by a lift, a gallery print, an information board in a corridor. Half the area of A1, and still large enough to carry a photograph or a full drawing extract with real presence.

Because A2 is usually read from a metre or less, it is the first size where image quality is judged close up. Photographs benefit from more resolution than the 150 dpi working target, and soft or over-compressed images that would pass at A0 across a room will not pass at A2 in a frame.

Common A2 work: retail and hospitality displays, exhibition and gallery prints, framed menus and event schedules, and full-bleed layout proofs for a creative team to check colour and typography at a believable size before committing to a longer run.

A3 printing — 297 × 420 mm

A3 is double A4 and the practical bridge between office printing and large format. It takes a table, a multi-column layout or a drawing extract that will not fit legibly on A4, and it still goes in a folder, a portfolio or a plan bag without being rolled.

It is the size most often ordered alongside something bigger: A0 plans for the wall with A3 copies for the meeting, or A1 posters for the window with A3 versions for the counter. Because the A series keeps its proportions, the same file prints at both sizes with no rework.

Typical A3 jobs: venue menus and notices, site safety information, presentation inserts, counter posters and short-run handouts. Matt where it will be written on or read in detail, photo satin where colour has to carry the page.

Turnaround, packing and delivery

Large format is genuinely same-day work: the machines are loaded and running, so a file approved in the morning is normally printed, checked and rolled within a couple of hours — subject to capacity and the size of the run. Because production runs through the night, files and approval by 21:00 are printed overnight for the morning. There is no fixed cut-off here: capacity decides, so call at any hour and you will get a straight yes or no on your deadline rather than a hopeful maybe.

In Central London a job is typically with you within the hour of coming off the press, by direct courier. Prints go out rolled in a tube as standard, because that is what survives a courier bag and a site office; say so at the order and they travel flat instead, which is worth it for anything going straight into a frame. Drawing sets can be folded to A4 with the title block out for filing — tell us which sheets to fold and which to leave rolled.

Collection is available round the clock. We are open 24 hours a day, 7 days a week, and the minimum order for after-hours collection or delivery is £95 plus courier if required; during normal hours there is no minimum. Call before you set off after 8pm so the job is ready at the counter rather than still on the machine.

When the job outgrows a sheet of paper

Bigger than the largest sheet. Above A0 the answer stops being paper: PVC banners run to 30 m on a single drop, roller banners stand up on their own for conferences and receptions, and exhibition graphics are cut to a stand drawing and delivered to the hall.

The same graphic on a rigid board. A poster that has to stand on an easel or survive outdoors wants a board rather than paper: Foamex for presentations indoors, Correx for temporary outdoor use, Dibond for anything permanent on a building.

Fabric instead of paper. For stands and events: printed tablecloths for the trestle tables, fabric pop-up displays for a seamless press wall, and feather flags for the entrance.

Same machines, different intent. If the job is specifically a poster or a photographic print rather than a sheet at a format, poster printing and canvas printing go into finishes, colour and mounting in more detail.