The short version: a mount is the card border that sits between your picture and the frame. It has a window cut in the middle, slightly smaller than the picture, so it holds the edges in place and gives the artwork some breathing space. In the US it's called a mat. A mount also keeps the picture from touching the glazing.
Below: what a mount actually does, how to choose the colour and border width, and how to work out which frame size you need once a mount is involved.
In this guide
What a mount does
- Gives the picture space. A border separates the artwork from the frame and the wall, so the eye goes straight to the picture. It's why framed prints in galleries almost always have one.
- Makes small pictures look bigger. A 6x4 photo in a 20 x 25 cm frame with a mount has far more presence than the same photo on its own.
- Fixes awkward sizes. If your picture doesn't match a standard frame, a mount cut to fit it lets you use a standard frame anyway.
- Keeps the glazing off the picture. The thickness of the mount holds the glazing a couple of millimetres away from the surface, which protects photos and prints from sticking or marking over time.
- Hides untidy edges. The window overlaps the edge of the picture, covering white borders, rough edges or slight unevenness.
The parts of a mount
| Term | What it means |
|---|---|
| Window or aperture | The opening in the middle that shows the picture. It's cut a few millimetres smaller than the picture on each side, so the mount holds the edges. |
| Border | The visible card between the window and the frame. |
| Bevel | The angled cut around the window, usually 45 degrees. It shows as a thin white or cream line that frames the picture. |
| Bottom weighting | Making the bottom border a little deeper than the top. It's a traditional look that stops the picture appearing to slide down. |
| Double mount | Two mounts layered together, with a thin line of the lower colour showing round the window. |
Choosing a mount colour
- White is the most popular choice and suits almost everything, especially modern prints and photography.
- Off-white, ivory or cream feels softer and suits older prints, botanical illustrations and warm-toned artwork. A bright white mount can make an aged or cream paper look dull.
- Black adds drama and works well with black and white photography and bold graphic prints.
- Coloured mounts can pick up a colour from the artwork, but use them carefully: a strong colour can compete with the picture.
If you're unsure, choose a white or off-white that's a shade lighter than the lightest part of the artwork.
How wide should the border be?
There's no fixed rule, but these are good starting points:
| Picture size | Typical border |
|---|---|
| Small (6x4, 7x5, A5) | 3 to 5 cm |
| Medium (A4, 20 x 25 cm) | 5 to 8 cm |
| Large (A3, 30 x 40 cm) | 6 to 10 cm |
| Very large (A2 and up) | 8 cm or more |
A border that's too thin looks like an afterthought; a generous one looks deliberate and gallery-like. For a contemporary look, go wider than you think.
Which frame size with a mount?
The frame needs to be the size of the picture plus the border on every side. Some common pairings with our UK frame sizes:
| Picture | Frame | Border |
|---|---|---|
| 6x4 photo | 20 x 25 cm | About 4.9 cm, even all round |
| 7x5 photo | 20 x 25 cm | About 3.6 cm, even all round |
| A4 print | A3 | About 4.4 cm at the sides, 6.2 cm top and bottom |
| A4 print | 40 x 50 cm | About 10 cm, nearly even |
| 30 x 40 cm print | 40 x 50 cm | 5 cm, even all round |
| A3 print | A2 | About 6.2 cm at the sides, 8.7 cm top and bottom |
Our picture frame size guide has more pairings. For any other size, or an exactly even border, our custom-cut mounts can be made to fit your picture and frame.
Key takeaways
- A mount is the card border between the picture and the frame. In the US it's called a mat.
- Its window is cut slightly smaller than the picture so it holds the edges.
- A mount gives the artwork space, keeps the glazing off it and lets odd sizes fit standard frames.
- White or off-white suits most artwork; aim for a border of about 5 to 8 cm on a medium print.
- With a mount, the frame must be the picture size plus the border on every side.
Common questions
What is a mount on a picture frame?
A card border between the picture and the frame, with a window cut in the middle to show the artwork. It frames the picture, holds it in place and keeps it away from the glazing.
Is a mount the same as a mat?
Yes. Mount is the usual UK term; mat or matte is the US term.
Do I need a mount?
No, but most artwork looks better with one, and it protects photos and prints from touching the glazing. Posters and canvas paintings are often framed without one.
What size mount do I need?
The outside of the mount matches the frame size, and the window is cut a few millimetres smaller than your picture on each side.
What colour mount is best?
White or off-white suits most pictures. Choose a shade a little lighter than the lightest part of the artwork, and use cream for older or warm-toned prints.
More framing guides: photo and picture frame sizes, how to frame a picture and how to see your artwork in a frame before you buy.
About the author: Trevor Beers
Trevor Beers is a guest writer for East Side Studio London. With two degrees in English language and a passion for contemporary art, he explores the intersections of culture, criticism, and collecting. Splitting his time between London and Austin, Trevor brings an academic eye to emerging art scenes, offering thoughtful perspectives on today's evolving art landscape.
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