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Which side of an emergency blanket reflects light the best? Pros Pleas

  1. Apr 18, 2013 #1
    Hello everyone. I have an indoor tomato grow going. The only reflective material I could get was those emergency blankets also known as a Mylar blanket, space blanket, first aid blanket, thermal blanket or weather blanket. I have them in 2 types:
    1. Gold on one side/silver on the other.
    2. Silver on both sides.

    I did some reading and found only about which side reflects heat better. And it was contradictory information anyway. There were mixed opinions. Some said gold reflects heat better, some said the silver side reflects heat better. But in regards to just silver-sided blankets there was a general agreement that the shinier side reflects heat better.

    But thats heat. I am interested in which side reflects light the best? I don't grasp physics well enough to know this. Maybe you smarter scientific fellows could help me out. Heat reflection doesn't interest me. All I care about is which side reflects light the best on both types of blankets?? I know mylar, panda plastic, etc. is way better reflectively. But these blankets is all I could get and all I have to work with, so please don't go off the subject.
    Also, would layering these blankets one on another improve light reflectivity? If so, which sides go together and in which order? Please educate this old timer, those of you who know their sh*t.
  2. jcsd
  3. Apr 18, 2013 #2


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    2017 Award

    Staff: Mentor

    Silver reflects more visible light than gold.
    See this graph, for example.
  4. Apr 18, 2013 #3
    Also note that neither side are actually made of silver or gold... that'd be a very expensive blanket. It's almost certainly made of aluminum, which is even better according to that figure.
  5. Apr 18, 2013 #4


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    Science Advisor
    Homework Helper

    Indeed. If you hadn't you already bought the mylar, aluminum kitchen foil would have been both cheaper and a better light reflector.

    I would use the silver side, because plants with green leaves reflect green light (that's why they are green!) and absorb the red and blue light from the spectrum to grow. So "yellow" light might be less efficient, even if the gold side seems to be more reflective.
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