Before starting to make a mat, decide on the type, the mounting method, and the aesthetic parameters.
Consider the following:
Physical preservation needs of the item:
Aesthetic or curatorial needs/wants:
1. Once you have decided on your type and materials, measure your object for the window mat. Be sure to measure your object in several places across each dimension to check for variation.
If the item will be overmatted (with the mat resting on the blank borders of the artwork), decide how much of the blank border you would like to show within the window around the media/art. Often ¼” is considered standard, but this may vary. The edge of the window mat should not fall directly on the edge of the object. If there is a large blank border around the image you may choose a larger overlap which will create a wider window mat. Make sure that your outer mat size will allow room for handling, usually at least 1" on each side.
If the item will be floated (having no part of the piece or even its borders behind the mat), determine how much of a border will be around the piece. This is often 1/8 to ¼” for smaller pieces; larger pieces may look better with a larger border. With floated objects, mats can be custom cut to conform to the border of a non-standard rectangle. However, slight variations in the gap between the edge of the object and window mat can be averaged to allow for the use of a standard rectangular window.
2. Cut your window mat, back board and wrapper to the same external size. Always check the fit of the window mat over the art before compiling your mat. (A slight error is not too hard to fix when you've just cut a mat, but can be heartbreaking if you've spent time carefully putting your mat together). A note about weighting: for storage mats, we usually center our single window mats. But if the aesthetic appeal or a curatorial decision dictates, it is fine to add weight to the bottom border (making it thicker).