Advice on internally non-reflective architectural film

Tintem · January 20

Thanks to everyone for your helpful replies.

I see that on Llumar's spec sheets, they list "clear glass" as having an internal visible reflectance % of 8%, and only their most extreme tints match that number. Does that mean that nearly all of their films are more internally reflective than untreated glass? I find that hard to believe.

They only have two films from the Harmony series which manage a lower internal VR number of 7, and they are non-reflective on the outside too.

Spec sheets:
https://llumar.com/content/dam/eastman/performance-films/llumar/nar/documents/english/arch/vista-arch-solar-safety-window-film-specs.pdf

https://llumar.com/content/dam/eastman/performance-films/llumar/tools-data/downloads-library/performance-data/arch-solar-control-window-film-specs-na.pdf

The whole exercise would be a bit pointless if the best I could do was match the the untreated glass' performance on the main feature I'm aiming for haha.

Edited January 20 by Tintem

OhioTint216 · January 20

20 minutes ago, Tintem said:

Thanks to everyone for your helpful replies.

I see that on Llumar's spec sheets, they list "clear glass" as having an internal visible reflectance % of 8%, and only their most extreme tints match that number. Does that mean that nearly all of their films are more internally reflective than untreated glass? I find that hard to believe.

They only have two films from the Harmony series which manage a lower internal VR number of 7, and they are non-reflective on the outside too.

Spec sheets:
https://llumar.com/content/dam/eastman/performance-films/llumar/nar/documents/english/arch/vista-arch-solar-safety-window-film-specs.pdf

https://llumar.com/content/dam/eastman/performance-films/llumar/tools-data/downloads-library/performance-data/arch-solar-control-window-film-specs-na.pdf

The whole exercise would be a bit pointless if the best I could do was match the the untreated glass' performance on the main feature I'm aiming for haha.

It's not really going to matter as much as to which brand you choose to go with - it's all going to be in the specs and how the film works. With LLumar, you will see less internal reflectivity on the more optically clear films - like the VS70 which can be a bit pricey, but its not going to solve your need of privacy.

In general, if you are looking to enhance your privacy - you will have to accept the fact that the film will have some reflectivity on the interior. Privacy and film is all about lighting and how the light is reflected from the film altering your perception.

I'd be careful going too dark in Harmony series, with higher absorption and low exterior reflectance - could be worried about thermal stress and glass breakage.

I have the V28 Film currently on my apartment windows, it works great for day time privacy with an exterior reflectance of 33%, but does have interior reflectivity (more noticeable at night than anything) as it is Dual Reflective. I've included some pictures.

https://ibb.co/bs6GxPw - Exterior
https://ibb.co/JqT8Kqt - Interior

Edited January 20 by OhioTint216

Tintem · January 20

20 minutes ago, OhioTint216 said:

It's not really going to matter as much as to which brand you choose to go with - it's all going to be in the specs and how the film works. With LLumar, you will see less internal reflectivity on the more optically clear films - like the VS70 which can be a bit pricey, but its not going to solve your need of privacy.

In general, if you are looking to enhance your privacy - you will have to accept the fact that the film will have some reflectivity on the interior. Privacy and film is all about lighting and how the light is reflected from the film altering your perception.

I'd be careful going too dark in Harmony series, with higher absorption and low exterior reflectance - could be worried about thermal stress and glass breakage.

I have the V28 Film currently on my apartment windows, it works great for day time privacy with an exterior reflectance of 33%, but does have interior reflectivity (more noticeable at night than anything) as it is Dual Reflective. I've included some pictures.

https://ibb.co/bs6GxPw - Exterior
https://ibb.co/JqT8Kqt - Interior

Thanks for the info and those pictures. I think that if privacy was my primary concern, I would be willing to accept a higher degree of internal reflectance. But lowering internal reflectance is the main concern.

For example, it is possible to get anti-reflective (AR) glass. It's used in art galleries, glasses, some phones, etc. I think I may have had a misconception that window films could get similar performance. Whereas it seems that the least reflective window films only get close to, or match, the internal reflectance of untreated glass.

Update:
I just found this stuff. I think it would be cheaper to get new windows lol.
https://www.mecanusa.com/Anti-Reflective-Glare-AR-AGAR-Film/Anti-Reflective-Film-Roll-Indoor.htm

Edited January 20 by Tintem

OhioTint216 · January 20

1 minute ago, Tintem said:

Thanks for the info and those pictures. I think that if privacy was my primary concern, I would be willing to accept a higher degree of internal reflectance. But lowering internal reflectance is the main concern.

For example, it is possible to get anti-reflective (AR) glass. It's used in art galleries, glasses, some phones, etc. I think I may have had a misconception that window films could get similar performance. Whereas it seems that the least reflective window films only get close to, or match, the internal reflectance of untreated glass.

The anti reflective properties are most likely to be achieved by the glass manufacturer. This is not something I have seen yet in the film industry, I did a quick search too and had a hard time finding anything.

It's probably safe to say most films are going to have some sort of reflectivity due to the materials it is made from - lowest you will probably get is close to or matching internal reflectance of the glass.

OhioTint216 · January 20

7 minutes ago, Tintem said:

Thanks for the info and those pictures. I think that if privacy was my primary concern, I would be willing to accept a higher degree of internal reflectance. But lowering internal reflectance is the main concern.

For example, it is possible to get anti-reflective (AR) glass. It's used in art galleries, glasses, some phones, etc. I think I may have had a misconception that window films could get similar performance. Whereas it seems that the least reflective window films only get close to, or match, the internal reflectance of untreated glass.

I spoke incorrectly - there are anti reflective films but not so much as for interior use. They are mainly used to stop reflection on the outside where the reflected light melts plastic siding. See link and photo.

https://www.decorativefilm.com/sx-1975-reflect-protect?gad_source=1&gclid=Cj0KCQiA-62tBhDSARIsAO7twbYNz_5dbxnSiLwe3JgvNv8Eu3dKZ1xMo4EgGoISZosk_YSvyU_hUlMaAjVZEALw_wcB

https://ibb.co/RQJ2XGw

The film is kinda funky looking, but that's just my opinion. Most people I have showed it to don't tend to like it very much.

Tintem · January 20

13 minutes ago, OhioTint216 said:

I spoke incorrectly - there are anti reflective films but not so much as for interior use. They are mainly used to stop reflection on the outside where the reflected light melts plastic siding. See link and photo.

https://www.decorativefilm.com/sx-1975-reflect-protect?gad_source=1&gclid=Cj0KCQiA-62tBhDSARIsAO7twbYNz_5dbxnSiLwe3JgvNv8Eu3dKZ1xMo4EgGoISZosk_YSvyU_hUlMaAjVZEALw_wcB

https://ibb.co/RQJ2XGw

The film is kinda funky looking, but that's just my opinion. Most people I have showed it to don't tend to like it very much.

Thanks for that. I have seen this type of film, quite funny to see it being installed where people's windows melted their turf or outdoor furniture. I think the other type I posted might be the only thing that would work (other than buying AR glass windows), but it's close to $100/ft so I probably won't be doing that!

Tintguy1980 · January 21

6 hours ago, Tintem said:

Update:
I just found this stuff. I think it would be cheaper to get new windows lol.
https://www.mecanusa.com/Anti-Reflective-Glare-AR-AGAR-Film/Anti-Reflective-Film-Roll-Indoor.htm

If the above product is a film that will mimic anti-reflect glass used in art framing then it may be the ticket. Anti-reflect glass used in framing and protecting art IS rather expensive. I have a piece of art that has that type glass, cracked now, and to replace it would have cost upwards of 200$ for 8" x 30" x 1/8". So I live with the crack.

Not sure what your objective is in achieving low-reflective interior surface. Is that all you want or are you looking for solar rejection properties as well? Like you have noted, Harmony is a film that states internal reflectivity at 7%. Keep in mind there is a margin of error of +/- 3% in any manufactured film product parameter. Also, the human eye begins to perceive reflectivity at 11-12% and above.

Tintem · January 23

On 1/21/2024 at 2:48 AM, Tintguy1980 said:

If the above product is a film that will mimic anti-reflect glass used in art framing then it may be the ticket. Anti-reflect glass used in framing and protecting art IS rather expensive. I have a piece of art that has that type glass, cracked now, and to replace it would have cost upwards of 200$ for 8" x 30" x 1/8". So I live with the crack.

Not sure what your objective is in achieving low-reflective interior surface. Is that all you want or are you looking for solar rejection properties as well? Like you have noted, Harmony is a film that states internal reflectivity at 7%. Keep in mind there is a margin of error of +/- 3% in any manufactured film product parameter. Also, the human eye begins to perceive reflectivity at 11-12% and above.

Yes well the main objective is to reduce internal reflectivity so that my indoor lights interfere less with the night time view. Privacy and glare reduction are secondary. It's surprising to me that the best I can do with architectural tint (i.e. lowest internal reflectivity) would be to match the reflectivity of regular glass. My windows seem pretty reflective already!

Edited January 23 by Tintem

Tintguy1980 · January 23

Physics really sucks.

If you're in a climate zone that demands dual-pane, reflectivity is elevated compared to single pane.

Then there's the problem with film products not being able to achieve lower than glass reflectivity without losing two-way visibility.

Buying and replacing existing glass with anti-reflect glass is way too pricey and if it were dual-pane, that would be special made and requiring twice the amount of anti-reflect glass.

Sucks doesn't it?

Tintem · January 23

2 hours ago, Tintguy1980 said:

Physics really sucks.

If you're in a climate zone that demands dual-pane, reflectivity is elevated compared to single pane.

Then there's the problem with film products not being able to achieve lower than glass reflectivity without losing two-way visibility.

Buying and replacing existing glass with anti-reflect glass is way too pricey and if it were dual-pane, that would be special made and requiring twice the amount of anti-reflect glass.

Sucks doesn't it?

Haha yes. And add to that the fact that the windows are nearly 100sqft each.

Part of me wonders what would happen if I laminated AR film and night vision ceramic film together. I suppose I would lose a lot of optical clarity at a minimum, but I'm wondering what the internal reflectivity would be like. I suspect that I would run into some physics limitations as you describe but I'd still be interested to try it out on a sample piece of glass.