The reason for use of “expensive cardboard” is two fold. Quality conservation materials that are acid free are more expensive. The other reason for the cost is chemcals and process for the color of the mat board.

As far as the method of achieving the window, for anyone setup for production mat cutting it will be much more labor intensive to assemble the four pieces than to cut the window. Especially since you have to cut the 4 pieces you are going to assemble before you start taking time to assemble them.

If you are concerned about conservation then you also to have to worry about making sure the adhesive used to assemble your mat will not cause the image to degrade.

Cheers,
Mark

Quote Originally Posted by dancqu View Post
What is a window mat? Two verticals and two
horizontals. Why not assemble a window mat
using the four components mentioned rather
than cut rectangular holes in expensive
card board?

Are there any who do assemble their
window mats? Dan