Start with one ratio and one size
A poster can only be printed at sizes that match its own shape. That shape is called the ratio, and the common ones are 2:3, 3:4 and 4:5. A 2:3 image prints well at 12x18 or 24x36 inches, but not at 18x24, because 18x24 is a 3:4 size.
For three posters in a row, pick one ratio and one size for all three. Mixed sizes need a clear focal point, usually one large piece with smaller ones around it, and three equal pieces already read as a set without any extra planning. If you pick one ratio, you also avoid pieces of the same width that end up with different heights.
- 2:3 ratio: 12x18, 16x24, 20x30 or 24x36 inches
- 3:4 ratio: 9x12, 12x16, 15x20, 18x24 or 24x32 inches
- 4:5 ratio: 8x10, 12x15, 16x20 or 24x30 inches
Measure the space before you pick a size
Designers suggest that art should cover about two-thirds of the width of the wall space, or of the furniture under it. For a 220 cm sofa, that means 140 to 150 cm of art. Count the whole row, gaps included, as one object.
Also measure the framed size, not the paper size. A frame with a 40 mm profile adds about 80 mm to the total width and height, which is enough to throw off the whole row.
- Measure the width of the wall space or the furniture below it.
- Multiply by two-thirds. That is the target width for the whole row.
- Subtract two gaps of 5 to 8 cm each.
- Divide what is left by three. That is the framed width of each poster.
- Subtract the frame border on both sides to find the poster width.
Set the height and the gaps
The usual gallery rule is to hang so the center of the group sits 145 to 155 cm (57 to 60 inches) above the floor. In a room where you mostly sit, such as a living room, use your seated eye level instead. Over a sofa or a table, leave 20 to 30 cm between the furniture and the bottom of the frames.
Keep the gap between frames at 5 to 8 cm (about 2 to 3 inches). Closer than 5 cm and the row can read as one confused image. Wider than 10 cm and it falls apart into three separate pictures. The gap between the first and second frame must equal the gap between the second and third.
Mock it up with paper before you make holes
A paper mock-up costs nothing and saves you from patching holes. Newspaper, wrapping paper or printer paper taped together all work.
- Cut three sheets of paper to the framed size of each poster.
- Mark the center line of the row on the wall with painter's tape.
- Tape the middle sheet up first, then add the left and right sheets outward from it.
- Measure each gap with a ruler. Do not judge it by eye.
- Step back and look from where you usually sit or stand. Move the sheets until it looks right.
- Mark the hanging points through the paper, take the paper down, then fit the hooks or nails.
Mistakes that make a set look off
Most problems with a three-poster row come from the same short list. Check each one before you hang.
Hanging too high or too close together is the most common. After that come uneven gaps, mixing many sizes with no focal point, choosing pieces too small for a large wall, forgetting the frame adds width, and skipping the paper mock-up.
- Hanging the row above eye level
- Gaps that differ from one frame to the next
- Pieces too small for the wall or furniture below
- Measuring the poster instead of the framed size
- Skipping the paper mock-up