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Diamond Hatch Pattern - Ceramic - Polarized SunGlasses

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For my wiki, what is the correct terminology I am observing


Ceramic Back Glass , looking direct from Drivers Seat - Polarized Sunglasses - everything is clear


Ceramic Back Glass, looking at rear view mirror, Polarizied Sunglasses

What I see is a diamond-eqsue pattern of greens/reds/and a smidge of yellow/oranish patterns across the whole film.


I'm sure there is a tint - technical word for what I am seeing.

Be curious what is it.

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It's called thin film interference. 


From wikipedia:

Thin-film interference is a natural phenomenon in which light waves reflected by the upper and lower boundaries of a thin film interfere with one another, either enhancing or reducing the reflected light. When the thickness of the film is an odd multiple of one quarter-wavelength of the light on it, the reflected waves from both surfaces interfere to cancel each other. Since the wave cannot be reflected, it is completely transmitted instead. When the thickness is a multiple of a half-wavelength of the light, the two reflected waves reinforce each other, increasing the reflection and reducing the transmission. Thus when white light, which consists of a range of wavelengths, is incident on the film, certain wavelengths (colors) are intensified while others are attenuated. Thin-film interference explains the multiple colors seen in light reflected from soap bubbles and oil films on water. It is also the mechanism behind the action of antireflection coatings used on glasses and camera lenses.



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IME, with ceramic and lighter 70%, when the sun hits it at a particular angle, it can appear hazy. Don't notice this on darker %


What is just weird with the combo I am seeing is mainly due to looking at my *6* in the rearview with polarized sunglasses. It's very distracting due to the -strong- Diamond colored pattern I'm seeing. It's 70% ceramic ontop of 20'ish factory dyed

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Automotive glass is curved, so rollers would not be culprit. Rollers would leave lines across the surface as the glass moves along in the process. Rollers are what produces gritty tempered glass surfaces most flat glass installers loathe. If the rollers are not kept absolutely clean of dust, the particles get fired into the glass surface.


Auto glass is tempered during the firing along with any black border coating, shaping the glass, or bake on defroster grid, all in one mold process. The glass is then cooled by air blasts from spaced nozzles. If the air temp from the nozzles runs amuck; i.e., too cool, you will see haze-white splotches laid out in a precise pattern (without polarized lenses), which at times can be either invisible at certain angles or more pronounced at low angle. I'm sure every tinter has seen these.


The surface of tempered glass is harder than it's core (think of seared Ahi tuna), this is where thin film interference is produced and gives us a rainbow of colored patterns while wearing polarized lenses. Look at a set of sliding glass doors with polarized lenses.


Or, look at the reflection of a set of sliders off the glass of a picture hanging on the wall nearby; in the right lighting you will see thin film interference at play (Edit: without polarized lenses).


Solution = non-polarized lenses.

Edited by Tintguy1980
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