BLOG QUESTION ADV: HOW TO ND A WINDOW

What is ND gel used for? Why would you want to use it on a window? What are two key factors in setting it up?

NDs are used to control the amount of light entering into the camera. It's helpful to use on a window when there's too much light coming from it. Having an lower exposure is important since it's harder to fix a blown-out image in post. When setting it up on a smaller set, you can either use gaff tape and tape it from the outside or use double sided tape and tape it from the inside. You want to be aware of any light leaks on the top. On an actual larger set, you can put an ND gel on a window by cleaning a window using windex and a squeegee spraying windex and cutting the excess. If you get dirt specks, you can scrape it off and use windex again to help break down those specks through the gel.