Inside
If you enter Inside measurements, the factory will deduct 1/8” from the width entered for proper fit. The preferred and most effective method of mounting roller shades is Inside the window opening. This places the fabric as close to the glass as possible (very desirable), and also minimizes side light gaps. However, not all windows allow for mounting inside the opening, such as when you span multiple windows with one shade. In this case, an Outside mount is required. If you enter Inside measurements, the factory will deduct 1/8” from the width entered for proper fit.
Outside
When a shade is to be made to the exact width with no deduction taken, Outside should be selected. The factory will make the shade exactly to the width entered. There is no deduction taken for the Height entered, regardless of whether you order as Inside or Outside measurement. Many pros will always order their shades as Outside so they have control over the amount of the deduction taken. Remember, Inside means the factory will deduct 1/8” from the width entered, Outside means no deduction will be taken from the width entered.
Fabric Width
There are times when the fabric width takes precedence over the cassette width. This usually occurs when mounting a roller shade above a window frame. In this case, the desired appearance is that the fabric be the same width as the window frame, while the cassette, since it’s mounted on the wall above the window, can be wider. Select Fabric Width to have the factory make the shade fabric the entered width. Just be aware the cassette will be wider than the fabric by about 1 ½” – 2”, so make sure there’s room for that where you’re mounting the cassette.