The four core picture framing materials are the mat (the border around your art), the moulding (the frame profile itself), the glazing (glass or acrylic that covers the art), and the backing (the rigid board behind it). Each one does a specific job, and choosing the right grade for each matters more for the long-term health of your artwork than most people expect. This guide walks through what each material is, the options available, and how to decide what fits your piece and budget.
Related service: custom framing services in Mississauga — serving Mississauga, Brampton and the GTA.
What does a mat board actually do?
A mat (sometimes called a “mount”) is the flat border that sits between your artwork and the frame. It serves two purposes: it creates visual breathing room so the eye rests on the art, and it holds the artwork away from the glass. That tiny air gap is important, because art pressed directly against glazing can stick, trap condensation, and develop mould over time.
Mat boards come in a few quality tiers:
- Paper / wood-pulp mats — the most affordable option, fine for posters and short-term display, but they contain acids that yellow and can leach into art over years.
- Acid-free (alpha-cellulose) mats — buffered to neutralise acidity, a strong middle-ground choice for most prints and photographs.
- Cotton rag (museum) mats — made from pure cotton fibre, the archival standard for valuable originals, limited editions, and heirloom pieces.
You’ll also choose between a single mat, a double mat (a second colour peeking through for an accent line), and the bevel cut, which is the angled inner edge revealing the white or coloured core of the board.
How do I choose the right frame moulding?
The moulding is the physical frame. Beyond colour and width, the main decision is the material it’s made from:
- Wood mouldings — warm and traditional, available in countless finishes and profiles. Solid hardwoods are heavier and well-suited to larger pieces.
- Metal mouldings — usually aluminium, giving a clean, slim, modern look. Lightweight and dimensionally stable, which makes them a favourite for photography and contemporary art.
- Composite / polystyrene mouldings — moulded synthetic profiles that mimic carved wood at a lower cost and weight.
Two practical points guide the choice: the weight of the finished piece (a large canvas or a heavy mirror needs a sturdier profile) and the rabbet depth — the recessed channel that has to be deep enough to hold the glazing, mat, art, and backing together. Shadow boxes and framed jerseys need especially deep mouldings to accommodate three-dimensional objects.
Glass or acrylic: which glazing should I pick?
Glazing is the transparent sheet that protects the front of your art. The two families are glass and acrylic (often sold under brand names like Plexiglas or Perspex), and within each there are upgrades.
- Standard clear glass — inexpensive and scratch-resistant, but reflective and offers little UV protection.
- Non-glare / anti-reflective glass — etched or coated to cut reflections, ideal for pieces hung opposite windows or lights.
- UV-filtering / conservation glass — blocks a large share of ultraviolet light, dramatically slowing fading of inks, watercolours, and photos.
- Acrylic glazing — roughly half the weight of glass and shatter-resistant, which is safer for big frames, children’s rooms, and shipping. It scratches more easily and can attract dust through static, so it isn’t ideal over charcoal or pastel work.
A simple rule: the more light-sensitive or irreplaceable the artwork, the more worthwhile UV-filtering glazing becomes.
Why does the backing board matter?
The backing is the rigid layer behind the art that keeps everything flat and supported. Like mats, backing comes in acidic (standard foam board or chipboard) and acid-free grades. For anything you care about preserving, an acid-free backing prevents the brown “acid burn” lines that migrate into paper over time.
Closely related are the mounting and hinging methods that attach the art to the backing. Archival framing uses reversible techniques — like Japanese-paper hinges or photo corners — rather than permanent dry-mounting or tape, so a valuable piece can always be removed unharmed.
How materials work together
No single material protects art on its own; they function as a system. Acid-free mats and backing guard against chemical damage from the inside, UV glazing defends against light from the outside, and a properly sized moulding holds the whole sandwich together with the correct air gap. Matching the grade of all four to the value of the piece is the heart of good framing. For fragile originals, our framers in Mississauga and Brampton generally recommend conservation-grade materials throughout; for a casual poster, standard materials are perfectly sensible.
Frequently asked questions
Is acid-free framing really necessary?
For posters and temporary décor, no. For photographs, original art, certificates, or anything sentimental, yes — acidic mats and backing slowly yellow and stain paper, and that damage is often irreversible.
What’s the difference between glass and acrylic glazing?
Glass is heavier, more rigid, and more scratch-resistant. Acrylic is lighter and shatter-resistant, making it safer for very large frames or shipping, though it scratches more easily and can build static.
Can I just buy a ready-made frame instead?
Ready-made frames work well for standard print sizes and budgets. Custom framing makes sense when your art is an unusual size, three-dimensional, or valuable enough to warrant conservation materials. If you’d like a professional to spec the right materials for your piece, explore our custom framing services in Mississauga.
