Postcard design specs: bleed, DPI, and safe zones without the jargon

A recovery card has one job — reopen a nearly-completed purchase — and about two seconds of attention to do it. Print quality is table stakes for those two seconds: a soft photo or a clipped edge reads as “mass mail,” and mass mail gets binned. The good news: print has exactly three physical rules, and all three are checkable before anything mails.

Rule one: 300 DPI, because paper doesn’t glow

A monitor hides softness; ink on card stock reports it faithfully. Print wants ~300 dots per inch — for a 4×6 card (printed at 6.25×4.25 inches, see bleed) that is 1875×1275 pixels of artwork. Around 180 DPI is the floor where photos survive but fine text suffers; below that, don’t print. A tool worth using measures your file and refuses ones that would embarrass you, before money is spent.

Rule two: bleed, because cutters drift

Cards are cut from larger sheets, and every cut wanders a fraction of a millimeter. Artwork sized exactly to 6×4 leaves hairline white slivers wherever the blade drifts outward. The fix is bleed: run backgrounds 0.125″ past the trim on all four sides. Design at 6.25×4.25; the outer ring is sacrificial.

Rule three: safe zones, because edges get eaten too

The same drift can clip content near the edge, so text and logos stay at least 0.125″ inside the trim. The back adds the big reservation: USPS overlays the address block and barcode on roughly the right half. The reliable pattern — design the front freely, keep the back functional (message, return address, QR into the shopper’s saved checkout), and let the mailing system lay out the address side.

The recovery-card checklist

• Landscape 1875×1275 px (or a print-exported PDF); backgrounds to the canvas edge.
• The abandoned product’s photo at honest resolution — it’s the most persuasive pixel on the card.
• One sentence of copy. The card’s job is reopening the checkout, not restating the catalog.
• Text an eighth-inch inside the trim; back’s address zone untouched.
• Expect print a touch darker than screen; test dark designs with a single card first.
• No printed discount codes — advertise the offer, mint the code at scan (why static codes leak).

Get the three rules right once, in a template, and every card after prints itself correctly — which is the point: recovery mail runs while you sleep, and the design should be one less thing it can get wrong.