Short answer: choose the overmat as the default and a float only when the sheet edge is part of the look; then settle the board, how the print is attached, how the print is kept off the glass, and whether the frame is deep enough for the whole stack. Write all of it in the brief and check it on a paid sample before the bulk run. The guidance is written for works on paper, so treat it as a quality reference and decide per product line how much of it to apply.
The six decisions
| Decision | What the guidance says | What to write in the brief |
|---|---|---|
| 1. Mat style | The Library of Congress says overmatting provides more protection than floating in the window. An overmat covers the sheet edges with an overlap of at least 2 mm to 4 mm; in a float the edges stay visible. | Overmat or float. For an overmat, the overlap. For a float, v-hinges and how the glazing gap is made. |
| 2. Board | Lignin-free: 100% cotton rag or chemically purified wood pulp. Acid-free is not the same as lignin-free. Most boards are buffered; unbuffered boards exist for sensitive photographic materials. 4-ply is a common starting thickness, thicker for large sheets. | Fibre, lignin-free, buffered or unbuffered, ply, and whether a Photographic Activity Test pass is needed for photographs. Ask for the board maker's technical data. |
| 3. Attachment | Non-adhesive corners or strips, or Japanese tissue hinges with wheat starch paste. Avoid self-adhesive tapes and tapes not made for conservation use; use no tape to secure the mat package in the frame. | The method, the hinge paper and the paste to be named in the quote, and no self-adhesive tape on the print. |
| 4. Glazing gap | The print should never touch the glazing. Use a sufficiently thick-ply window mat or spacers along the perimeter of the mat. | How the gap is made: mat thickness or spacers. |
| 5. Frame depth | The rabbet must hold the glazing, mat, art and backing; the frame must be deep enough for the whole package. NEDCC says the mat and backing board should fit with 1/16 to 1/8 inch of total play. | The stack to be held, and a check of its thickness against the moulding depth on a sample. |
| 6. Brief and sample | Order a paid sample and check the mat edge, the attachment method and the glazing gap before you commit to a bulk run. | Put the choices from decisions 1 to 5 on the order brief and ask for the method to be shown on the approved sample. |
What we can and cannot say
A photo mount is an option inside our photo frames, and it changes the visible picture area, so give the picture size and the opening you want. Whether a particular board grade or mounting method can be supplied on your order is confirmed in your quote, not promised here. For a rare or valuable piece, ask a conservator.
Related: overmat vs floating mount, hinges, corners and adhesives, conservation matboard and mounting, the statements as data, the photo frame order brief.
Start an enquiry when your brief is ready; we reply within 1 business day, with questions or a quote.
Sources: conservation matboard and mounting for framed prints [S38]; overmat vs floating mount [S41]; hinges, corners and adhesives for mounting a print [S42]; photo frame profiles compared [S19]. As of 2026-11-12. Terms are typical and are confirmed in your written quote.