Best Reflective Films - tested

Hello folks, let's do some tests! The title is self explanatory.

The Equipment:

Mini Cab with easily replaceable films


Licor Li250 quantum meter



(not pictured) fixed cfl lamp with mini reflector.

Films tested: Easygrow Light tight, Easygrow Diamond, local off brand diamond diffusion, Orca, Panda, Sunfilm Mylar, no material

I'm down to see how this pans out

hi longkai,
i guess ur lightmeter will not be accurate enough for 2016. u need to watch the PAR over LUX or Lumen cuz this is what u want to mesure for plants.
i would compare different bubs too, for example a small hps, cfm, cmh, led could perform a little differently too. because of different light angles and intensity
and maybe mesuring one "white wallcolour" setup. could surprise many people who spent money on mylar and panda
that would be my "dream test"
but i am interested in your test as well and lookig forward for results
have fun

And the results:

The best reflective material provided 40% more light than no material, the aluminum based materials all produced a 30-40% increase, while the Orca and Panda films only provided a 20% increase.

In the order of total reflectivity: Easygrow Light tight > Sunfilm Mylar > Easygrow Diamond > off brand diamond >> Orca > Panda

The evenness of the reflection was determined by first subtracting the no reflector number from the total, then taking the difference between each point and the average, and finally adding up all the differences. The evenness of the reflection is ordered as follows:

Panda > Orca >> Easygrow Diamond = off brand diamond >> Light Tight > Mylar

Some discussion:

Having some reflective material is MUCH better than nothing. The yield difference could potentially be %40.

The Orca film underperformed. They have great marketing, but the results don't back up their claims. Firstly, the Orca film sample (from a full roll I paid for), has faint uneven splotches which indicate that their layer of Barium Sulfate (I assume) was too thin to provide full reflectivity. Secondly, their online tests

https://www.youtube.com/watch?v=c020_4EdIW0
https://www.youtube.com/watch?v=TW8l_IOLqCk

do not accurately portray real growing conditions. Their setup is done in such a way where most of the light must have at least 2 reflections before it can reach the meter, which heavily favors the diffuse reflection pattern of the material. In real world grow conditions, most of the light that is lost from the sides of a light can be recovered by a single specular (non diffuse) reflection. In fact, having a diffuse reflection causes a lot of light to be reflected upward away from the canopy and lost.

The mylar and light tight produced hot spots that gave double the light readings of weaker points, sometimes right next to each other. However, with larger grow spaces and distances, these effects should even out.

The diamond diffusion films evened out some of the hot spots, but traded it for less total reflectivity at the bottom surface. Having a name brand helps. Aluminized mylar comes in several grades of reflectivity, and you get what you pay for.

My recommendation: For a small grow or one where hot spots matter (many small plants in veg, for example), go with a good aluminized mylar diamond diffusion film. For a larger grow (4+ lights) go with the flat mylar films.

cannaisok said:

hi longkai,
i guess ur lightmeter will not be accurate enough for 2016. u need to watch the PAR over LUX or Lumen cuz this is what u want to mesure for plants.
i would compare different bubs too, for example a small hps, cfm, cmh, led could perform a little differently too. because of different light angles and intensity
and maybe mesuring one "white wallcolour" setup. could surprise many people who spent money on mylar and panda
that would be my "dream test"
but i am interested in your test as well and lookig forward for results
have fun

Click to expand...

You have a point about different light reflectors and the angles they produce, but the physics should theoretically be the same for any light spectrum/source. Light is light, and the difference wavelengths do not significantly affect how it reflects off of surfaces.

The Licor is the best PAR meter you can use outside of a full spectrometer. It is the scientific standard for horticultural research and offers a near perfect response curve from the 400-700nm spectrum.

Longkai,
Thanks for your work. Interesting, but you left out what a lot of people use. White Latex Paint. I believe it to be a good alternative and a money saver. Could you use your equipment to test it, por favor? Thanks. -granger

great longi,
you did your homework!
Looking forward to see ur results!
thank you for making a few points i was going to research closer but never did like that every nm spec is reflected same way, this has been a theory in my head 4 a long time now. like what is if a 630nm is radiated vs 450nm for example.
is it reflected same may from one surface? white plastic film as it is from white paper or aluminum or...
more and more variables apperar in my head the longer i think about this. rly have to do more homework, do you have some literature or any link about this theme maybe?

and again, i am still a believer in white pain water or chemical based.
for example: have a little experiment box 1.5x1.5 with 5x 10watts leds inside. this closet was high grade creme colored material with a uneven texture lika a plastic mousepad and it was a "ok reflective wall" for me for about half a year.
then i had the idea of placing a white papera on one side and my eyes liked it. saw a can of very white radiatorpain for heaters and metal rails. I applied it to the walls and it was stinking for 3 days. but in the end it was a LOT brighter, even brighter than papersheets.
have to check my digicam if i have before vs after pictures.
excuse my english
thanks , cannaisok

I'll do the white latex paint test in a couple of days. I have some Behr Marquee Ultra Pure White leftover.

In my mind, 2 x 0 = 0, or for arguments sake, 100 x 0 still equals a big fat useless 0. That's my opinion of the benefit of reflected light, maybe better than zero or nothing, but really not worthy of any effort or expense in this day and age...

Titanium oxide vivid white paint reflects reasonably. Well worth a test in your shoot out.

@prune
dude, how comes this oppinion? lets say overall reflection power is 5-15% of the total grow(in smaller spaces maybe little more).
now white pain or orca/panda/mylar we have to buy only one time for theoretically many years. many grows
its cheap and provides extra light forever=extra photosynthesis=extra bud
i dont think that this 10% of light can harm you.
I grow only in very small spaces like 3x3 or 2x2 and reflective walls are a must have for me.

White paint tests came in.

It is slightly more reflective than orca film, which is surprising, and it's slightly more uneven than the panda film. Overall the reflectivity and smoothness are on about the same level as orca film, and the amount of light recovered is a step below the aluminized mylar films.

longkai47 said:

White paint tests came in.

It is slightly more reflective than orca film, which is surprising, and it's slightly more uneven than the panda film. Overall the reflectivity and smoothness are on about the same level as orca film, and the amount of light recovered is a step below the aluminized mylar films.

Click to expand...

My favorite reflective material is still reflectix insulation not sure how it stacks up against others, but I like the design and seems effective. If you get a chance to test it I'd be curious how it stacks up against the others listed.

Thanks for the test man!
Im impressed that plain white did even better than 80$ Orca
Titaniumoxide is very important for white paint, it reflects a little more light. but wall-colour white is OK, too. if u have a running grow and dont want to remove ur plants for days/weeks out the growroom.
One growroom i panted took ONE week to dry until the stank was not that horrible. and the plants inside stupped crippling cuz of poisones air

I thought Orca was supposed to be the best.

Thanks for doing the test.

How do those films compare to a bathroom mirror (silvered glass) or polished stainless ?

Thanks for the info you got so far !

I think orca is supposed to be superior because it reflects the full spectrum of light better than the others, where as a lot of the others reflect some spectrums very well but others poorly. I'm no scientist tho.

I think beta test team did some tests or posted some scientific type charts and graphs on it from other people's or maybe some university tests. Don't recall exactly but I know he's a nerd with that kinda stuff and all about the orca.

Longkai,
Thanks for testing the white paint. I'm not surprised at the results. The reflected light is a small portion of the light the plants receive. If one material reflects 3% more of the small amount of total light the plant receives, no le hace. I think it comes down to what you like, cost, ease of installation, and maintenance. -granger

bump

Good to know that flat white paint is not a wives tale from the grow bible!