How to use this

Every red number is editable: click it, type, press Enter. Fractions work — 11 1/2, 3/8, or plain 7.375. Everything rounds to 1/16″. Escape cancels an edit in progress; the browser's Back button undoes.

The numbers

• Mat — top-left corner.
• Print — the two numbers on the crosshair inside the print.
• Reveal — the paper border left showing around the print, set separately for top/sides and bottom.
• Top margin — the mat's top edge down to the opening.

Laying out a print

Set the mat, then the print. The opening is always centered left to right, so the only decision left is vertical: click the top margin and choose from the list.

• Equal sides — top margin matches the side margins, and the slack falls to the bottom.
• Optical center — 5/11 of the leftover height.
• Golden ratio — 0.382 of it.
• 60 / 40 — 0.4 of it.

Layouts that would sit the print at or below the middle of the mat aren't offered.

Also

• Drag a photograph onto the print to preview it in place.
• The address bar holds the whole layout — bookmark it, or send it to someone.