We recently went to a job site where in a bank of skylight window panes, some glass was tinted and some glass was not. The glass was thought to be filmed aftermarket and therefore removable, and since matching film is tough and rarely exact and the client wanted them all match, the decision was made that it would be easier to remove the film from the tinted panes than film the untinted panes.
However, when the crew arrived to do the work, it took them less than five minutes to determine the skylights were in fact factory tinted, which they could do nothing about.
So how do you tell if your existing windows are after-market filmed or factory (in-line) tinted?
First, if the glass is high up, get a ladder so you can get close. It’s almost impossible to tell from a distance unless you are looking at really old film that’s obviously peeling off or deteriorating. But even then, it’s better to get close and know for sure. Then try these tricks:
1) Run your fingernails along the very edge of the interior side of the glass and see if you can catch the edge of the film. Sometimes the edges will be tucked under gaskets, so it can be tough, but usually this is the quickest way to tell.
2) Scan the edges, especially the corners, for tiny little dust-caught-in-adhesive spots. Even the most professional & experienced tinted will have a hard time getting the corners totally free of these miniscule spots that you would never see unless you are looking for them. So look for them. Sometimes it’s easier to see these spots on the exterior side of the glass, they can show up with a silvery look because of the tiny halo around the dust where the adhesive didn’t get to stick to glass.
3) If you know you want to remove the film if it is after-market and you are able, then take an Xacto knife (with a blade safe for glass) & actually cut at the edges & see if it starts to come up.
There are other possibilities, such as double-pane windows that were after-market tinted or coated on surface two or three (the interior side of the exterior pane or exterior side of interior pane) then enclosed, so they may have little dust spots and/or old-age deterioration, but you can’t get to it to remove. Or windows which are factory tinted and then after-market filmed over that. Or the possibility that a few of the windows in a bank are factory and other are after-market filmed to best match, so you should always check them all if you are to remove film from them all.