Why Does Window Tint Turn Purple

It's a question that has plagued humanity for centuries and one that has been hard for us to find an answer to: Will all window tint eventually turn purple? Okay, maybe it hasn't quite plagued all of humanity for centuries but the question about whether or not all window film you install on your car or truck will turn purple someday is one that has caused a lot of head scratching in the auto enthusiast community. And as much as we'd like to be able to tell you that we've finally figured it out and come up with the definitive answer to the purple tint conundrum that's just not going to happen. There's no consensus about the cause, but many experts believe the purple color comes from a failure of the dye caused by UV rays.

An Artifact of the Dying Process

Begin by taking an uncut piece of tint, spray both sides with soapy water and lay it on outside of the rear windshield liner-side up. You will then squeegee a horizontal anchor onto the film to gather all the excess film into "fingers" at the top and bottoms of the window.

Probably the most common explanation of why window film turns purple is as a result of the dyes used to tint the process. There are a few different schools of thought on this but the two major lines of thinking seem to be that either it is the nature of the dyes themselves or that the film has been dyed after the UV coating was applied. In regard to the first claim, that "purpling" (yeah, we're just going to make that word up if you don't mind) is a result of the failure of the dyes, I have heard both that it is a more common occurrence with cheaper, no-lifetime warranted films and that it is inevitable with all dyed film. Although we won't name names, there have been reports that even film made by the big boys who charge a premium eventually turns purple.

According to one source the purple effect is is due to the fact that "yellow and green are the weakest dyes, leaving blue and red to remain as the stronger colors, which of course combine to make purple. Today's color stable dye technology centers around the discovery of more stable yellow." (Source: Tintdude Forums) In essence, this explanation views the purpling to be a result of the breakdown of the dyes which is simply a result of their interaction with UV rays and heat.

The next explanation, which makes the least amount of sense to us, is that the dyes have been impregnated over the UV coating. If someone could explain how that works we might consider it but for all intents and purposes we'll consider that explanation to be debunked.

The Final Analysis

In essence, any window film that is dyed is made of a of polyester film impregnated with dyes to achieve the desired color and darkness. The purple appearance is caused by ultraviolet rays from the sun and heat which break down the dyes in any dyed film, regardless of the quality although films that are higher quality will tend not to turn purple as those with less of a UV coating. An alternative to dyed films are those which are metalized. These films costs a little more but the metalized film process deposits aluminum, titanium or other metals on the polyester to replace the dyes, created on extremely stable products. At Rvinyl, we do not carry metalized films as they can interfere with electronic equipment but there are a number of manufacturers who do.

We hope we've at least given you some guidance on the purple tint issue and at least put your mind to rest about it. We offer two grades of film under the Rtint window film series: a 3-year warranted film and a lifetime-warranted film. Whichever you choose you can rest assured knowing that our films will not to turn purple, bubble, peel or fade before the expiration of the warranty period if ever. So, if you feel you're ready to jump in and try your hand at window tint go ahead and pick up a precut kit or sheet here but if you still have questions that can't be easily answered over the phone or in a brief email check out our our selection of articles that cover every aspect of automotive window tint purchasing, percentages, installation and more. And, last but not least, if you don't see a topic that you would like to know more about, suggest it to us by send us an email here.