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Understanding UV block out window film help please!
Hello All,
i wonder if anyone has a good understanding of UV block out film and can help me please? We have fitted a UV block out film to a shop window, (single pane glass) as per the manufacturers guidelines, and our client is complaining the film doesn’t work and the clothes are still fading.We have three shops with the same material and all from the same roll. All others clients happy. We think it is the lighting system this chap has above the window on the inside shining down onto the clothes. We have bought a UVA and UVB light meter to check the film. The problem is the meter has three settings:
40mW, 4000uW and 400uW.I am trying to find out more about the so we can test the film in front of the client and show him either the film works or not, and find out if the lights are the problem. The manufacturers of the film have sent me a data sheet and some readings but they are percentages and i cant find out how to match them to our readings. Owner of shop now threatening to sue for cost of damaged clothing so i need to find out more info and get on top of this. Is there a UK window film specialist that anyone recommends that maybe i could chat to? Any info appreciated, or any relevant google links.
thanks in advance
Dan
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9 Replies
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What film? Can you post the spec sheet?
If they have discharge lighting, eg. Metal halide / mercury discharge /HID they can give off a LOT of harmful UV if they are lacking a built in filter.
Halogens less so, fluorescent almost nil. -
hi Dan
I fit a lot of UV film to shop windows, but you have to first explain to the customer that fading is caused by far more than UV.
The causes of fading are
UV responsible for 40%
Visible Light responsible for 25%
Solar Energy (We explain this as Infra Red or heat) responsible for 25%
Miscelleneous responsible for 10% (this is natural dye pygment degredation and other factors we can not do anything about.OK so almost any window film will remove 99% of UV and the very best Dermagard Films claim to get 99.9%, but if that is a clear film then it still only reduces actual fading by 40- 49% so things will still fade, only slower.
A dark film such as Silver 20 will reduce the 25% portion due to visible light by 85% and the 25% Solar Energy portion by 69%. So even that leaves when worked out roughly to the total causes of fading reduces fading by only 78%.
BUT obviously of course you can’t use silver 20 on a shop window or no one could see into it.
So its all about compromise and asking the customer what degree of tint they are prepared to use as any slight tint will increase the protection but never eliminate fading.I have draw up this chart and explanation for customers to show customers what protection they can expect from a variety of different tints. So as long as this is explained to customers in advance they are usually happy to even get a 60% reduction in fading while still haveing to rotate stock in the window.
Usually on a shop window I use Solar Gard Sterling 70 or Sterling 60, darker than that the reflection is too much. i use these films as they are what we call spectrally selective. This means they eliminate more IR than a normal film for a particular degree of light transmission.
I know nothing about the UV from lamps that David has mentioned but this hopefully explains the limitations of film.
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Hi Guys,
thanks for taking the time to reply. I think i was not googling the correct terms. David i have found an interesting chart which explains about different light bulbs effects, and Stuart, thanks for that information, very useful. I am going in today to take the readings and send them off to the film manufacturer, to check the film is doing its job, and then look at the other factors that might be causing the fade.thanks
Dan
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What film did you use Dan?
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Reflectiv UVA 151 which is their recommended shop window no fade film. Data Sheet attached
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Using the specs given from that film tyou could only expect a 50% reduction in the amount of fading.
It is not really any better than a totally clear security film.They say it cuts 99% of UV, which it does of course and many people will buy it thinking that is the same as fading, but as I explained in my first post there are other factors involved and really as a reputable dealer they should explain this.
However it is unfortunately a misunderstanding amongst people not in the trade that UV = fading.
Reflectiv are a french firm and its best to seek advice from some of the british distributors such as Bonwyke or Solar Gard.
Not sure sending the film back to them for tesing will be of any use as I’m sure it will be doing what it says it the limitations and expectations which are out.
Next question, where did you buy it and who sold it to you.
I have some dealings with Reflectiv only because they offer a range of coloured films that others don’t but I have never found ther specs or advice up to a par with more well know firms established in the UK. -
We bought it in Mallorca the nearest dealer point.
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Ah ha sorry didn’t realise you were not in UK.
It does what it says its the customer expectations which have to be addressed and that should really start with whoever sold the film explaning the causes of fading and the limitations of different films.
Some are slightly better as you can see from my table but in reality even the best films that you could use on a shop window can only expect a 60% reduction of fading. I always tell customers they can expect around a 50-60% reduction which means they can leave stock in a window about twice as long as without film for the same amount of fading. Usually they are happy with this extra time but do still realise fading will occur.
Solar gard have this visual and make sure all their dealers explain this. Right side of screen
http://www.solargard.com/window-films/r … protection -
Mr Miller is spot on as per usual, the general consensus is that if you block UV you stop fading which as Stuart has explained is incorrect.
The other thing I have noticed from experience is that Fabrics are more prone to fading mainly due to the dye pigments making up the colours of the garments/fabric.
At best you can reduce the effect but you cannot eliminate fading.
Bob
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