refection question

RM3

Well-Known Member
A lesson for ya :)

Ever read the debate over Mylar or Flat white paint ? which is best and why?

here is a very deep look into it that most growers are unaware of,,,

most growers only look at reflective properties ,,,

Mylar: 90% to 95%

Flat White Paint: 85% to 93%

Semi Gloss White Paint: 75% to 80%

Flat Yellow Paint: 70% to 80%

Aluminum Foil: 70% to 75%

Flat Black Paint: less than 10%

with the best flat white paint being Titanium Dioxide

most growers do not consider refraction or diffusion properties but these do matter somewhat

The refractive index of Mylar is 1.5 ~ 1.52

from here,,,
http://www.cidraprecisionservices.co...yethylene.html

The refractive index for Titanium Dioxide is 2.55 ~ 2.73

from here,,,,
http://www2.dupont.com/Titanium_Tech...s_Brochure.pdf

and then there is the thing that no growers consider Emissivity

the definition of Emissivity is ,,,

Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a blackbody (a perfect emitter) at the same temperature and wavelength and under the same viewing conditions.

a basic primer for Emissivity can be found here,,,
http://www.electro-optical.com/eoi_p...Is+Emissivity?

The Emissivity of Mylar is .59

The Emissivity of Titanium white paint is .92

from here,,,,
http://www.electro-optical.com/eoi_p...of%20Materials

This is why the Leprechaun uses flat white paint
 

Sativied

Well-Known Member
and then there is the thing that no growers consider Emissivity

the definition of Emissivity is ,,,

Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a blackbody (a perfect emitter) at the same temperature and wavelength and under the same viewing conditions.

The Emissivity of Mylar is .59

The Emissivity of Titanium white paint is .92
A hypothetical perfect mirror has an emittance equal to 0.0.

Emittance of human skin is nearly 1.0.

Higher is not better in this context. Emission is inverse proportional to reflection and proportional the absorption.

Good reflectors are poor emitters. Good emitters are poor reflectors. With the best emitter and the worst reflector being the hypothetical blackbody that absorbs all from every wavelength and direction. There's no free energy.

upload_2015-1-3_20-23-18.png

upload_2015-1-3_20-23-28.png
^^ISS

upload_2015-1-3_20-56-0.png
^^NASA

Also, with a proper hood and light you already have plenty of diffusion, the purpose of reflection is to control the path of the light, essentially extending the hood. Although I do agree some diffusing along the way can beneficial.
 

johnny781

Member
A lesson for ya :)

Ever read the debate over Mylar or Flat white paint ? which is best and why?

here is a very deep look into it that most growers are unaware of,,,

most growers only look at reflective properties ,,,

Mylar: 90% to 95%

Flat White Paint: 85% to 93%

Semi Gloss White Paint: 75% to 80%

Flat Yellow Paint: 70% to 80%

Aluminum Foil: 70% to 75%

Flat Black Paint: less than 10%

with the best flat white paint being Titanium Dioxide

most growers do not consider refraction or diffusion properties but these do matter somewhat

The refractive index of Mylar is 1.5 ~ 1.52

from here,,,
http://www.cidraprecisionservices.co...yethylene.html

The refractive index for Titanium Dioxide is 2.55 ~ 2.73

from here,,,,
http://www2.dupont.com/Titanium_Tech...s_Brochure.pdf

and then there is the thing that no growers consider Emissivity

the definition of Emissivity is ,,,

Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a blackbody (a perfect emitter) at the same temperature and wavelength and under the same viewing conditions.

a basic primer for Emissivity can be found here,,,
http://www.electro-optical.com/eoi_p...Is+Emissivity?

The Emissivity of Mylar is .59

The Emissivity of Titanium white paint is .92

from here,,,,
http://www.electro-optical.com/eoi_p...of%20Materials

This is why the Leprechaun uses flat white paint
Ic yeah idk I have flat white paint and it just looks dull compared to when I had tin foil up but I found the tin foil acted like a ray gun lol it put burn holes in the leafs but it just looks so dull
 

johnny781

Member
Nah kind of on a budget so far I've spent 40 bucks on the whole grow just for nutes and ph up &down. . & a test . And 5 gal buckets the rest I collected or I had or. Five fingered it
Oh and built right now I'm wOrking on my drying chamber14203343176782097774687.jpg
 

johnny781

Member
Well if u call Five fifingerin taking a fan that didn't work so they had it on display the cord was cut so I grabbed it and rewired it
 
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