What is the difference between 'flip on long edge' and 'flip on short edge'?

'Flip on long edge' means the paper is flipped along its longer side — correct for portrait (tall) documents, exactly like turning pages in a book. 'Flip on short edge' means flipping over the top or bottom — correct for landscape (wide) documents like calendars or landscape-oriented presentations.

My double-sided document has alternate pages upside down — what went wrong?

You selected the wrong flip direction. For a portrait document, you need 'long edge flip.' If you chose 'short edge flip' by mistake, the back of each sheet is rotated 180 degrees relative to the front, making every even page appear upside down. Re-order with the correct setting.

What margin should I leave for double-sided binding?

Set mirrored margins so the inner (gutter) margin is at least 25 mm for spiral or wiro binding, 30–35 mm for perfect binding, and 15–20 mm for saddle-stitch. The outer margin can be 15–20 mm. In Word, use Layout > Margins > Mirror Margins to set this automatically.

Does double-sided printing cost less than single-sided?

Yes — duplex printing uses half as many sheets, reducing paper cost. The per-impression (per page side) cost may be similar, but the total paper cost for a 200-page document drops from 200 sheets to 100 sheets. On Printster, the price calculator shows accurate duplex pricing for your document.

Can I mix single-sided and double-sided pages in one order?

Typically, a single print job is either all single-sided or all double-sided. If you need some pages printed single-sided (for example, a colour cover followed by double-sided body pages), this is usually specified as a separate job or as a colour cover add-on when ordering online.

How do I ensure my PDF is in the correct order for double-sided printing?

Your PDF should simply be in normal reading order (page 1, 2, 3, 4...). The online printer handles the physical feeding and flipping to produce correct output. You do not need to manually rearrange pages unless you are producing a saddle-stitch booklet and the printer asks for 'printer spreads' specifically.

How to Set Up Double-Sided Printing

To set up a PDF for correct double-sided printing, ensure your page count is even, check that odd pages are right-hand pages and even pages are left-hand pages, set the correct binding edge (long-edge flip for portrait, short-edge flip for landscape), and confirm your margins include adequate space on the gutter side. When ordering from an online service, select 'duplex' or 'double-sided' and choose 'flip on long edge' for portrait documents.

Double-sided (duplex) printing is one of the most effective ways to reduce paper consumption and make printed documents easier to carry — a 200-page study guide becomes 100 sheets instead of 200. But a document that is set up incorrectly for double-sided printing produces output where the back of one page is upside down, or where the left and right pages are mismatched, or where text runs into the binding because the gutter margin is too small. The good news is that if you get a few fundamentals right when preparing your file, double-sided printing is straightforward. This guide covers the key concepts — flip direction, gutter margins, and page order — so your double-sided document reads correctly every time.

Long-Edge vs Short-Edge Flip

When a sheet of paper is printed on both sides, it must be flipped along an edge to align the pages correctly. The correct flip direction depends on the document orientation:

Portrait (tall) documents: flip along the long edge (the left/right side). This is how books work — when you turn a page, you flip along the left spine.
Landscape (wide) documents: flip along the short edge (the top/bottom). This is how spiral-bound landscape notebooks work — you flip over the top.

Choosing the wrong flip direction produces a document where alternate pages are upside down. When ordering from Printster, select 'duplex' and then 'flip on long edge' for standard portrait A4 documents.

Even Page Count

A double-sided document must have an even page count. If your PDF has 23 pages, the last sheet will have content on the front and a blank back. This is fine — it is standard practice. Either leave it, or add a blank page 24 to make the total even. For bound documents, page counts that are multiples of four look cleanest.

Gutter Margins for Binding

The 'gutter' is the margin on the binding edge — the inner margin between the page content and the spine. For single-sided documents, margins can be equal on all sides. For double-sided (facing-page) documents that will be bound:

Set mirrored margins so the gutter is on the right of odd pages and the left of even pages
Minimum gutter for spiral/wiro binding: 25 mm
For perfect binding (glue): 30–35 mm (glue binding hides more of the inner margin)
For saddle-stitch (staple): 15–20 mm is usually sufficient

In Microsoft Word: Layout > Margins > Custom Margins > Multiple pages: Mirror margins, then set the 'Inside' margin to your gutter width.

Page Order and Imposition

For a standard reading document (thesis, report, manual), pages are in natural order: 1, 2, 3, 4... This is 'reading order' or 'normal' imposition. Your PDF should be in this order.

For saddle-stitched booklets, page imposition is different — the physical sheet order does not match reading order. For example, on a 16-page booklet, sheet 1 has pages 16 and 1 on it (cover back and cover front). Most professional printers handle imposition automatically from your reading-order PDF, so you do not need to manually re-order your pages — just upload in reading order and confirm with the printer.

Uploading to Printster

When placing an order on Printster, select 'Double-sided (duplex)' printing. For portrait documents, the long-edge flip setting produces correct output. The price calculator automatically adjusts to show the per-page rate and total cost. Duplex printing reduces your per-sheet cost compared to single-sided. Delivery is 4–7 working days for Delhi NCR and 7–10 working days for the rest of India from the next working day after your order is placed.

Upload your file & get an instant price

Frequently asked questions

What is the difference between 'flip on long edge' and 'flip on short edge'?: 'Flip on long edge' means the paper is flipped along its longer side — correct for portrait (tall) documents, exactly like turning pages in a book. 'Flip on short edge' means flipping over the top or bottom — correct for landscape (wide) documents like calendars or landscape-oriented presentations.
My double-sided document has alternate pages upside down — what went wrong?: You selected the wrong flip direction. For a portrait document, you need 'long edge flip.' If you chose 'short edge flip' by mistake, the back of each sheet is rotated 180 degrees relative to the front, making every even page appear upside down. Re-order with the correct setting.
What margin should I leave for double-sided binding?: Set mirrored margins so the inner (gutter) margin is at least 25 mm for spiral or wiro binding, 30–35 mm for perfect binding, and 15–20 mm for saddle-stitch. The outer margin can be 15–20 mm. In Word, use Layout > Margins > Mirror Margins to set this automatically.
Does double-sided printing cost less than single-sided?: Yes — duplex printing uses half as many sheets, reducing paper cost. The per-impression (per page side) cost may be similar, but the total paper cost for a 200-page document drops from 200 sheets to 100 sheets. On Printster, the price calculator shows accurate duplex pricing for your document.
Can I mix single-sided and double-sided pages in one order?: Typically, a single print job is either all single-sided or all double-sided. If you need some pages printed single-sided (for example, a colour cover followed by double-sided body pages), this is usually specified as a separate job or as a colour cover add-on when ordering online.
How do I ensure my PDF is in the correct order for double-sided printing?: Your PDF should simply be in normal reading order (page 1, 2, 3, 4...). The online printer handles the physical feeding and flipping to produce correct output. You do not need to manually rearrange pages unless you are producing a saddle-stitch booklet and the printer asks for 'printer spreads' specifically.