tinfoil lining

[pcduck]

BB everything absorbs and reflects light..Otherwise you would not see it

even black objects

 

[BBFan]

The reason a mirror works is that it doesn't absorb nearly any light at all (only a fractional amount)- those photons hitting it get bounced back. In a flat mirror- those photons are being reflected back to you in a linear (specular) way.

A true black object can only be seen by reference to the objects around it. No light escapes it.

 

[pcduck]

Objects reflect the color you see and absorb the remaining colors.

A true black object can only exist in space as a black hole. I do not grow in space or near a black hole which would be impossible because of the gravitational pull of the black hole.

A true black object can only be seen by reference to the objects around it. No light escapes it.

Does this mean my black buckets which I think nearly everyone would say are black in color can not be seen or do not exists?

 

[PencilHead]

yea i put the dull side out hahaha the shiny side scared me. gunna go get some flat white tomorrow. will the fresh paint have an affect on my plant?

Latex won't unless it's still wet and your plants stick to it..

PS--Sorry about staying on topic.

 

[pcduck]

No problem PH

We should have been there long ago...sorry gang

 

[leafminer]

Aluminum foil is made to absorb heat and evenly distribute the heat.
In this case heat is light. Aluminum foil absorbs the light and evenly distributes the heat from the light.

Mirrors are they same they absorb your image/light in order for you to see yourself.

Aluminum foil sucks for grow room walls but works great for cooking

Leafminer What is your reference that states that Aluminum foil is 90% reflective?

- Well, unfortunately I used to be a physics teacher at High School so I can't resist:

1. Aluminium foil does not absorb light, it reflects it. That is the reason why they use it in the giant solar energy projects out in the deserts.

2. You have exactly the wrong idea of how mirrors work. If they absorb your image/light they would appear black. A mirror reflects almost all light. 98% efficiency at the silver surface, but another 2-4% is lost due to the transmittivity of the glass, so roughly 95% efficient. There is no reason not to use mirrors, except for: expense, weight, fragility... well that's plenty of reasons I guess but not to do with reflectance.

3. Actually I was incorrect with my 90% figure for foil. It is actually higher than that, when new. 98% - same as Mylar. Unlike Mylar it is opaque to light, very useful property in grow rooms. See:
hXXp://www.azom.com/Details.asp?ArticleID=1435
(This is an aluminium foil manufacturer's own comments - NOT a forum or other "opinion" - I deal in FACTS)
Reflectivity: Reflects approximately 98% of radiant heat and light.


and from Alufoil:
hXXp://www.alufoil.org/front_content.php?idart=204
Reflectivity: Reflects approximately 98% of radiant heat and light. There is no difference between the reflectivity of a bright and a matte foil surface.

So the only reason NOT to use foil is the intelligent reason quoted by one poster, that it is electrically conductive and so increases the risk of shock . . . but only if your lamps and circuitry is ALREADY dangerous (i.e. 'live)

But I suppose my provision of facts and figures and web site references will never convince those who somehow don't believe science but prefer to rely on old grower's tales and nonsense. :ignore:

 

[leafminer]

Objects reflect the color you see and absorb the remaining colors.

A true black object can only exist in space as a black hole. I do not grow in space or near a black hole which would be impossible because of the gravitational pull of the black hole.

Does this mean my black buckets which I think nearly everyone would say are black in color can not be seen or do not exists?

- You can see them because they are not perfectly black, they do return some light. Otherwise you would not 'see' them but instead be aware of them as 'black' spaces in your field of view. As an example of this I photographed a plant against a black bin bag the other day. It looked black to me. But when I cropped it with PS4 I saw immediately that the 'black' background was really a dark grey.

 

[Growdude]

Listen, The reason mirrors don't work is the light is reflected not refracted.
Refracted light spreads out the light across the wall, direct reflection will only pinpoint the light.

Question, have you ever sen any grow guides recommending mirrors? if they are so great why are they not even listed as a choice?

 

[nouvellechef]

This thread is getting interesting. IDK. I just saw a greenhouse seed co grow that has black curtains all the way around and ceiling is black. 13 week cheese and colas the size of some NFL players arms. So you decide.

 

[captain1]

I have a ton of mirrors dont know if they will fit I should try it. To me it has to be better than Panda.Only thing is I have all different strains so there wouldnt be a control group.

 

[leafminer]

Listen, The reason mirrors don't work is the light is reflected not refracted.
Refracted light spreads out the light across the wall, direct reflection will only pinpoint the light.

Question, have you ever sen any grow guides recommending mirrors? if they are so great why are they not even listed as a choice?

Because they are too expensive and too fragile and too heavy. As I already said.
Growdude, you obviously did take some physics at school . . . but unfortunately, you've got it wrong. Everything we use in the grow room should be reflective. REFRACTION applies to lenses. The first law of reflection states:
"The angle of incidence is equal to the angle of reflection". A plane mirror cannot 'pinpoint the light'. You'd need a parabolic mirror to do that.

 

[leafminer]

Can I use Aluminium Foil?
Aluminum foil is no more than 55% reflective. If used, make sure that the dull side is the one that is used to reflect the light. When it becomes creased its reflectivity is even lower (around 35%.) It is also very dangerous to use because it is electrically conductive, and is a fire hazard when it is in close contact with HID lighting.

Aluminum foil creates hotspots easily, and attaching this to walls is a pain and usually using aluminum tape or glue is the best way. This should only be used as a last resort, and even then its usefulness is questionable.

Can I use mirrors for reflectivity?
A mirror dosen't reflect light, just image. A mirror is basically reflective backed glass and the glass will absorb light (and also refract it), since the light travels through the glass 2 times it makes it even worse.


just some quotes i ran across.

Puffinnugs, all those quotes are complete nonsense. Total and absolute nonsense. It often seems to me that nobody in a MJ forum has either been to school or, if they did, remembers anything from their science lessons. I'm not blaming you, just the dumbkopfs who post such nonsense.

 

[captain1]

Can I use mirrors for reflectivity?
A mirror dosen't reflect light, just image. A mirror is basically reflective backed glass and the glass will absorb light (and also refract it), since the light travels through the glass 2 times it makes it even worse.


just some quotes i ran across.

How can someone say it doesnt reflect light? have you ever taken a mirror and shined light at someone? Even a watch glass for that matter it sure does reflect light. Why does your bathroom get brighter when you put up a mirror? I not a professional at this but seems people have heard from a friend from a website from there grandma it doesnt work with no real facts behind it.

FYI I love a good argument no disrespect to anyone just interesting to hear peoples views on things.

 

[BBFan]

Interesting though where people get information from and how it becomes gospel.

Mirrors are, imho, not a good item to use in a grow room. It is not because they lack reflectivity, but rather because they reflect light in a specular, or linear way. If light hits a mirror at 45 degrees, it will reflect that light at 45 degrees. Diffused light (not refracted) is better. It is a lower reflectivity, but a more efficient one.

Aluminum foil, imho, is also not good for use in a grow room. Not because it doesn't reflect light very efficiently, but rather because of the issues mentioned earlier.

Just my opinions. I don't like an argument, but I do enjoy a discussion where people put forth differing opinions or present facts in a courteous manner.

 

[Growdude]

Interesting though where people get information from and how it becomes gospel.

Mirrors are, imho, not a good item to use in a grow room. It is not because they lack reflectivity, but rather because they reflect light in a specular, or linear way. If light hits a mirror at 45 degrees, it will reflect that light at 45 degrees. Diffused light (not refracted) is better. It is a lower reflectivity, but a more efficient one.

Aluminum foil, imho, is also not good for use in a grow room. Not because it doesn't reflect light very efficiently, but rather because of the issues mentioned earlier.

Just my opinions. I don't like an argument, but I do enjoy a discussion where people put forth differing opinions or present facts in a courteous manner.

This is what im saying, though I am prob. using the wrong term (refraction vs diffused.

 

[Icex420]

All my statements ive posted are just opinions i guess.. From what ive read from reputable sources like hick etc..

You guys both have quotes from scientists. And they disagree.

You ever took a mirror outside and tilted it at an angle to get it to hit the ground? Its extremely bright and hot. Hot enough to light a dry leaf on fire in under 20 seconds.I dont know if this can be replicated under a hps light, but i imagine it could to a degree.

Who knows? =/

 

[leafminer]

Icex420, you can try this in the Sahara and it will not set a leaf on fire.
The light reflected by the mirror is slightly (5%) less hot than the light received directly from the sun. Think about this, please. Use logic.
That is because the mirror is a PLANE mirror (flat). If you used a concave mirror you could set a leaf on fire.
The lamps in our grow rooms are nowhere near the intensity of sunlight.
The only concave mirrors we use in grow rooms are the lamp reflectors, and we need them.

 

[BBFan]

Icex420, you can try this in the Sahara and it will not set a leaf on fire.
The light reflected by the mirror is slightly (5%) less hot than the light received directly from the sun. Think about this, please. Use logic.
That is because the mirror is a PLANE mirror (flat). If you used a concave mirror you could set a leaf on fire.
The lamps in our grow rooms are nowhere near the intensity of sunlight.
The only concave mirrors we use in grow rooms are the lamp reflectors, and we need them.

Leafminer-

I agree with you.

Can you be a little nicer about it?

 

[2Dog]

I have heard of mirrors with light/sun causing fires..makes me nervous.

 

[Icex420]

Icex420, you can try this in the Sahara and it will not set a leaf on fire.
The light reflected by the mirror is slightly (5%) less hot than the light received directly from the sun. Think about this, please. Use logic.
That is because the mirror is a PLANE mirror (flat). If you used a concave mirror you could set a leaf on fire.
The lamps in our grow rooms are nowhere near the intensity of sunlight.
The only concave mirrors we use in grow rooms are the lamp reflectors, and we need them.

Ah interesting. I stand corrected.

I must of had a special mirror when i tried it. I vaguely remember this.