Once you have a settled on a reading of the artwork, you will want to decide how you are going to present the artwork in the window of the mat. You can display just the image in the window of the mat, hiding any unprinted area surrounding the image beneath the borders. Or you may elect to show some of the unprinted area surrounding the image. Or you may elect to show the paper complete, which means you will show the edges of the paper inside the window of the mat.
Your decision should be based on stylistic considerations. For example, presenting only the image is a more contemporary approach evocative of artwork that spreads or "bleeds" to the very edges of the paper. Presenting the image as well as the unprinted area surrounding it is a more traditional approach, frequently used with prints and absolutely essential when the print is signed and numbered below the image. Showing the paper complete is an approach frequently used when the paper lends value to the presentation, as with a handmade paper or a paper suggestive of the composition, such as a Japanese painting on rice paper or Egyptian hieroglyphs on papyrus.
When matting a bleed—that is, displaying only the image in the window of the mat—the window is generally a half inch smaller than the dimensions of the image. Therefore, if the image is 8"x 10", the window size is 7 1/2" x 9 1/4" . By making the window smaller by a half inch on each dimension, the window's edges encroach on the edges of the image by a quarter inch at each edge; and if the image is the same size as the paper, this quarter inch is sufficient to hold the paper within the window (Figure B-1).
When matting to display both the image and the unprinted area surrounding it, determining the size of the window is a simple matter of measuring the area that consists of the image plus the unprinted area surrounding it, and then cutting the mat's window to that size (Figure B-2). Thus, if the image is 8"x 10" and you want to expose an additional half inch of surrounding area, the window size will be 8 1/2" x 10 1/2"—an entirely different window size than would be called for if the same artwork was matted as a bleed.
When matting to display the paper complete in the window of the mat, the artwork is first mounted against a mat blank (Figure B-3). A mat blank is a piece of matboard that has been reduced from the full size sheet to the frame size but doesn't have a window cut in it. Artwork can be mounted against a mat blank for presentation without a window mat. Such a presentation is called a float because the artwork is suspended or "floated" against the mat blank with the means of support concealed behind the artwork.
When matting to display the paper complete, the framer first floats the artwork and then places a window mat over it (Figure B-4). In this case, the window of the mat is larger than the artwork so that the edges of the paper are revealed. In addition, a margin of the mat blank on which the artwork is mounted is revealed. The degree of this reveal is up to the individual, but let's say the image is 8"x 10" and the paper is 10"x 12" (meaning there is a 1" wide margin of unprinted area surrounding the image). To show the paper complete in the window of the mat with a half-inch wide reveal of the mat blank along each edge, the window size will be 11"x 13".
The point is, the way you decide to present the artwork in the window of the mat impacts the size of the window, and since measuring for matting and framing requires us to build from the artwork size outward to the frame size, the first step in the measuring process is to determine the window size. The next step is to determine the sizes of the mat borders that will surround the window. And then, by adding mat borders to the window size, you will arrive at the frame size. This process will be detailed below. But for purposes of measuring it's very important to note that the frame size is not actually the size of the frame when measured from edge to edge but rather is the size of the recess within the frame that will accept the framing components; i.e., the mat, the backing board and glass. As a result, the perimeter sizes of the mat, backing board and glass are all the same as the frame size. Hence, working outward to the perimeter size of the mat is the same thing as working outward to the frame size.