SWIMoryou
Active Member
BOught Wrapping paper that was silver seemsd to have better reflectivity of foil, and slightly less than mylar
Best Reflective Material?
- Thread starter sirus420
- Start date
BOught Wrapping paper that was silver seemsd to have better reflectivity of foil, and slightly less than mylar
FilthyFletch
Mr I Can Do That For Half
Do not use foil of emergency blankets ie space blankets as they suck at reflection and cause hot spots that can cause heat burn and uneven lighting. Flat white paint reflects well but if you want something more go to most dollar stores and look for gift wrap called polywrap. Its mettallic looking can be colors but the back is regular silver. It is made from a thinner mylar but works well and is a buck a roll usually 3 ft x 10 ft. Good grows
SWIMoryou
Active Member
The silver wrapping paper at a craft store seems to have better reflectivity than foil but no hot spots like mylar
FilthyFletch
Mr I Can Do That For Half
A hot spot is when the material does not reflect evenly some places allow more light to pass through and others reflect more making a warmer are and uneven light similar to if you stand in indirect sunlight then in direct uncovered sunlight. You feel the heat from the different light intensitys making a hotspot which in small close proximities can cause a burn or heat stress
the reflected light can't be any hotter then the light itself. reflecting light doesn't intensify it. does it?
Brick Top
New Member
Reflecting heat and reflecting all the different spectrums of light are two different things. Not all spectrums of light produce heat or much of it.
LEDs produce 100% PAR light but they put off almost no heat at all. The combination of low energy use and the light spectrums LEDs put out that are not heat-producing spectrums equates to extremely low temperatures.
Almost all of the heat put off by other forms of lights are in spectrums that are not beneficial to plant growth so there is no benefit from reflecting them and there should be no desire to do so.
You do not want to reflect heat, you want to reflect light and mainly in the light spectrums that you plants need the most.
Aluminum foil reflects between 50% and 55% of light rays.
Flat White paint reflects between 80% and 85% of light rays.
Mylar reflects between 90% to 92% of light rays.
In the case of light hoods/reflectors a quality pebbled or textured model will reflect 95%+ of light rays.
Brick Top
New Member
It focuses an increased amount of light and heat on localized areas rather than evenly distributing it around the entire grow area.
The key to reflective material is the optimal diffusing of light, spreading it out as evenly as possible over the largest area as possible.
Imagine you and a friend were standing side by side outside on a hot sunny day and someone was holding a mirror reflecting light directly on you but not on your friend. Do you believe that after a while you would begin to notice a difference due to the increased amount of light being directed at you?
That is what aluminum foil and other low grade reflective materials do, they focus more light on certain areas and that means increased temperatures not above that of the temperature of the light itself but above that of the average of the overall area. It also means that some other areas will receive less light due to the unequal diffusing of light rays.
so if i'm standing out in the sun with my friend and it's 100 degrees out and he reflects some sunlight onto me it will be 100+ where that light is? i'm not buying it. reflecting light does NOT increase temps. MAGNIFYING light does though.
Bonafide925
Active Member
I'd have to go with Aluminum Foil. So, ALUMINUM FOIL FTW!!!
Brick Top
New Member
No, you misunderstood what I said. I clearly said it does not increase the temperature over that of the heat off the bulb but it does focus more heat on certain areas because aluminum foil does not diffuse light equally.
If for example the temperature in your grow room is 70 degrees and you can pick the temperature of your lights heat since I have no idea of what lighting you are using and with an uneven/unequal diffusing of light rays more light and more heat will strike certain areas.
That does not mean those areas will be hotter than the temperature of the heat put off by your lighting but it will be hotter than the normal and average temperature of the overall grow room.
Also since some light spectrums can cause bleaching in plants by focusing more light rays on certain areas you increase the risk of localized bleaching and those leaves will not absorb and process light rays as efficiently as they otherwise would.
The equal and even diffusing of light rays is a key element of growing and the main purpose for using a reflective material.
As for the example of you and your friend standing outside what will happen is that you will be at much higher risk of a sunburn than your friend will be because of the increased amount of light rays that are hitting you than are hitting him.
It is like how you can and will get a worse sunburn on a boat on a lake than you will sunning yourself on your deck. The water reflects light rays and they strike you increasing the amount of light rays hitting your body.
Now it is much less of a problem for those using CFLs than it is for those using HID lighting. CFLs do not put out an equal amount of heat as HID lighting and remember that heat from light is in different spectrums and they are reflected along with all the other light spectrums and any reflective material that does not equally diffuse all the light that strikes it and instead focuses some of it on localized areas will increase the temperature in those areas, again not above that of the highest temperature but higher than other areas will have and higher than all areas would have with an equal even diffusing of all light rays.
Being that so many members here are so in love with CFLs they have likely never experienced the problems that using aluminum foil will cause, or at least not to a degree that they noticed or even began to consider it could possibly be a problem so in their minds the problem does not exist but it does in fact exist and far more so if using HID lighting.
Billybmann91
Member
Those are not good to get! They will burn your plants
ProHuman
Well-Known Member
A List of Reflective Materials and their Reflectivity.
Materials Reflectivity
Foylon ..................................................... 95%
Mylar ....................................................... 92-97%
Elastomere (roofing)Paint ............................. 90%
White/Black Plastic (poly).............................. 75-90%
Polystyrene Foam Sheeting (styrofoam)............ 75-85%
Flat White Paint .......................................... 75-85%
Emergency Blanket ...................................... 70%
Semi-Gloss White Paint ............................... 55-60%
Aluminum Foil ........................................... 35-55%
More Details and Explanations can be found online, here is a link to my
source: https://www.icmag.com/modules/Tutorials/Lighting/1486.htm
Materials Reflectivity
Foylon ..................................................... 95%
Mylar ....................................................... 92-97%
Elastomere (roofing)Paint ............................. 90%
White/Black Plastic (poly).............................. 75-90%
Polystyrene Foam Sheeting (styrofoam)............ 75-85%
Flat White Paint .......................................... 75-85%
Emergency Blanket ...................................... 70%
Semi-Gloss White Paint ............................... 55-60%
Aluminum Foil ........................................... 35-55%
More Details and Explanations can be found online, here is a link to my
source: https://www.icmag.com/modules/Tutorials/Lighting/1486.htm
GreenfingersUK
Active Member
I've recently upgraded to Orca film with impressive results. Expensive by the roll, but not too bad by the meter.
[Quote = "FilthyFletch, post: 2175738, člen: 4959"] hot spot je, když materiál neodráží rovnoměrně některá místa umožní více světla projít a jiné odráží víc dělat teplejší jsou i nerovnoměrný světlo podobné, pokud stojíte v nepřímém slunečním světle pak na přímém slunečním světle nekryté. Můžete cítit teplo z různých světelných intensitys dělat hotspot, který v malých blízkých proximities může způsobit popálení nebo tepelného stresu [/ quote]
.. Popáleniny od slunce pomocí zrcadel nebo lupy není způsoben odrazem velkého množství světla, ale kvůli vyššímu záření UVA, UVB a pocit tepla kvůli vyššímu záření infračervené .. zcela upřímně, Zajímalo by mě, co může způsobit hotspotů na rostliny, jsem toho názoru, že jediným možným případem je, pokud nerovnoměrně dodržovat pomačkaný list a bude klást jednoduché odraz zintenzivnit odraz na jednom místě a vytvořili hotspot, nehoří, ale příliš mnoho světla intenzity ozáření ..
.. Popáleniny od slunce pomocí zrcadel nebo lupy není způsoben odrazem velkého množství světla, ale kvůli vyššímu záření UVA, UVB a pocit tepla kvůli vyššímu záření infračervené .. zcela upřímně, Zajímalo by mě, co může způsobit hotspotů na rostliny, jsem toho názoru, že jediným možným případem je, pokud nerovnoměrně dodržovat pomačkaný list a bude klást jednoduché odraz zintenzivnit odraz na jednom místě a vytvořili hotspot, nehoří, ale příliš mnoho světla intenzity ozáření ..