Why Old Tint Turns Purple, and What to Do
· 4 min read
The short answer
Purple window tint is dyed film whose dye has broken down under UV, and the colour does not come back — it has to be removed and replaced. The removal itself is straightforward on side glass but genuinely risky on the rear window, where the defroster grid is printed on the same inside surface the film sits on. A razor takes those lines off with the tint and they can't be put back. Steam lifts the film without touching the grid, which is why we use it.
Why it happens#
Dyed film is the cheapest way to make glass dark: a layer of dye between adhesive and a protective coating. UV breaks the dye down. In Central Texas that takes a few summers, and the dye fails unevenly — the blues go first, which is why what's left reads violet. It's not dirt and it's not fixable. The film has to come off.
- Purple and faded — the dye has gone. Permanent.
- Bubbling — the adhesive has failed. Bubbles spread and never lie back down.
- Peeling edges — usually a bad cut years ago, now lifting.
- Hazy and scratched — old film clouds up and takes the view with it. Worst at night.
The rear window is the whole job#
What removal costs#
It's quoted once we've seen the film, because a peeling corner and a baked-on purple rear window are not the same job. Film from last year peels off in sheets. Film from 2009 comes off in pieces. Removal costs less when we're putting new film on the same visit, since the glass only gets prepped once.
Can I remove window tint myself?
On side glass, carefully, with a steamer and patience — yes. On the rear window, we'd genuinely advise against it. The defroster grid is unforgiving and a replacement rear window costs several times what the removal does.
Will new tint go over the old film?
No. Film has to bond to clean glass. The old layer and its adhesive come off first, every time. Anyone offering to lay new film over old is setting up a callback.
