How to Frame a Picture/Calculate the sizes

  • Keep a workbook of notes and measurements, so that you can track back specifics
  • Extra space at bottom of frame, unless frame re-use needed.
  • Always measure off the frame

Diagram showing coloured areas for art (red), matting (green), and frame (blue).

Matt width - 5cm.

The calculations are in centimeters.

Width Height
Artwork <ArtWidth> <ArtHeight>
Inner edge (red) <ArtWidth> - 1 <ArtHeight> - 1 Need overlap to keep picture in place
Matt size (green) <ArtWidth>-1 + (2*<MattWidth>) <ArtHeight>-1 + (2*<MattHeight>) +1 extra matt at bottom to stop optical illusion of frame leaning forward
Frame size (blue) <ArtWidth>-1+(2*<MattWidth>) +(2*<FrameWidth>) <ArtHeight>-1+(2*<MattHeight>)+1 +(2*<FrameHeight>)

Which means that ...

you need this much frame prior to cutting: left + right + top + bottom

2*(<ArtWidth>-1+(2*<MattWidth>)+(2*<FrameWidth>))+ 2 * (<ArtHeight>-1+(2*<MattHeight>)+1+(2*<FrameHeight>)) = (2*<ArtWidth>)-2+(4*<MattWidth>)+(4*<FrameWidth>)+ (2*<ArtHeight>)+(4*<MattHeight>)+(4*<FrameHeight>)

Measuring for MountsEdit

Someone should merge this section into the above.

Calculating the Mount Size (to be cut from a sheet of mount board).

  1. Decide how much of the picture you want to show (add to, or take away from the art size) = WINDOW SIZE.
  2. Decide how much mount you want around the window (margins).
    • Top and both sides are the same.
    • For bottom margin allow extra 20% to compensate for the optical illusion which makes the bottom border seem narrower than it actually is.
    • Standard margin sizes:
      • Top and sides 50mm, bottom 65mm.
      • Top and sides 65mm, bottom 75mm.
      • Top and sides 75mm, bottom 90mm.
    • Allow for width of frame rebate by adding that amount to each margin width = MARGIN WIDTH.
  3. Therefore MOUNT HEIGHT = rebate allowance + top margin + window height + bottom margin + rebate allowance.
  4. Therefore MOUNT WIDTH = rebate allowance + right margin + window width + left margin + rebate allowance.