# Paint reflector in white ?



## eminor (31 Mar 2022)

Hello i have an odyssera fixture which have some kind of parabolic reflector which seems not that good, i have the idea to paint it in white,  is white paint really better ? thx

reflector looks like this


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## Hanuman (31 Mar 2022)

eminor said:


> kind of parabolic reflector which seems not that good


In what sense is it not good? Seems to me the reflector has a silver polish which will reflect more light than plain white which will absorb some of the light.


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## oreo57 (31 Mar 2022)

Hanuman said:


> In what sense is it not good? Seems to me the reflector has a silver polish which will reflect more light than plain white which will absorb some of the light.


Actually that isn't really true, well for some white paints..
aluminum..black line






White paint..




Probably splitting hairs her though..


Extra special white paint:








						Researchers Created the Whitest White Paint Ever
					

In creating the whitest paint ever, which researchers say reflects up to 98.1% of light, the Purdue researchers are outdoing their own record, set just last fall, when they developed a paint that reflects 95.5% of sunlight.




					gizmodo.com
				




Anyways about the orig. post..
Would not recommend white paint soo close to even that cool of a bulb.
Latex paints are plastics basically.

Next if you do use white paint add Barium sulfate.


			https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1010&context=cpl_techniquesinstruments


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## oreo57 (31 Mar 2022)

eminor said:


> Hello i have an odyssera fixture which have some kind of parabolic reflector which seems not that good, i have the idea to paint it in white,  is white paint really better ? thx
> 
> reflector looks like this
> 
> ...


On a more practical level you could possibly replace that sheet reflector w/ ind reflectors.
Greenhouse suppliers or hydroponic stores may have something..
T5 reflector ATI | T5 / T8 reflectors | Lighting

Main problem is more of geometry than material..

Try to find something like this and see if it fits..


> SunBlaster NanoTech T5 Reflector​


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## Hanuman (31 Mar 2022)

oreo57 said:


> Actually that isn't really true, well for some white paints..
> aluminum..black line
> 
> 
> ...


That graph doesn't tell me much. It's pretty generic. What's the source of that? What exactly is white paint here? There are literally thousands of white paints, the exceedingly large majority of which will have inferior reflectance compared to designed reflectors made of aluminium or other highly reflective materials.


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## oreo57 (31 Mar 2022)

Going back to my orig article..





			https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1010&context=cpl_techniquesinstruments
		

And this..








						Basic Properties of Mirrors - Introduction to Mirrors | オリンパス ライフサイエンス
					

Basic Properties of Mirrors - Introduction to Mirrors




					www.olympus-lifescience.com
				




Lets just say they are pretty equal "as is".
 White better with more Ba Sulfate added.

Spectralon is basically "Teflon"

I can find better and worse al charts..Mylar sucks btw in comparison..





						Reflectance vs Wavelength
					

plastic microfiber technology creates highly reflective and diffuse reflection over full visible spectrum; eliminates hot spots and creates an even, efficient distribution of light on plants in gardeners hydroponic grow room. Yield increasing product outperforms metalized foil products like...



					www.orcagrowfilm.com
				











						FIG. 1. Spectral reflectance of aluminum and various other metals. ( Ó...
					

Download scientific diagram | Spectral reflectance of aluminum and various other metals. ( Ó Elsevier. Reprinted with permission from L. Li. 22  from publication: Laser-based Surface Modifications of Aluminum and its Alloys | Aluminum (Al) and its alloys have widespread engineering applications...




					www.researchgate.net
				








soo we have "some" aluminums, "some" whites..








						Metallic Mirror Coatings | Edmund Optics
					

Want to learn more about metallic mirror coatings? Find information about standard and custom metallic mirror coatings that are available at Edmund Optics.



					www.edmundoptics.com
				









						Pro-Lite: Barium Sulphate Coating
					

Barium sulphate paints from Pro-Lite provide diffuse reflectance in the UV-VIS-NIR spectral region



					www.pro-lite.co.uk
				




Getting past this diversion.. as I said their problem wasn't the "color" but the geometry of the reflector.


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## Hanuman (31 Mar 2022)

oreo57 said:


> Mylar sucks btw in comparison..


Allow me to take that statement coming from a company that produces a competing reflective film product as not being entirely partial. But let's say for a second it does suck.
I am not expert in light, but I think there is a good reason why companies use aluminium or equivalent reflectors made of non white color. Cost perhaps? Now, will engineered white paints or white reflective material reflect better, maybe. But realistically speaking the OP is simply asking if he should paint his reflector in white and the chances that he uses a specifically designed product that will reflect light better are probably infinitesimal small. The assumption here is that he would use the old plain wall or spray paint which I don't see that reflecting light any better, most probably reflecting it worse. Hence my first comment. Just my opinion. I could be wrong.


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## oreo57 (31 Mar 2022)

Hanuman said:


> Allow me to take that statement coming from a company that produces a competing reflective film product as not being entirely partial. But let's say for a second it does suck.
> I am not expert in light, but I think there is a good reason why companies use aluminium or equivalent reflectors made of non white color. Cost perhaps? Now, will engineered white paints or white reflective material reflect better, maybe. But realistically speaking the OP is simply asking if he should paint his reflector in white and the chances that he uses a specifically designed product that will reflect light better are probably infinitesimal small. The assumption here is that he would use the old plain wall or spray paint which I don't see that reflecting light any better, most probably reflecting it worse. Just my opinion. I could be wrong.


Right, like I stated.. it was the geomoetry of the reflector not the substance.
Sorry the white thing is a tangent I probably shouldn't have ventured on..

As to companies.. well a white finish, even if better than polished aluminum probably won't look very good after awhile and maintenance is more difficult. Think chipping paint ect.
Certainly easier to clean and polish than white Ba laced paint. 
To use something even better than both.. teflon coated reflectors would be prohibitively costly.

Industry RARELY uses "the best" just the most practical.. and then markets the heck out of it.
The vid you posted (only scanned it) shows about the difference between flat white and "the best" is about 10%
10% of 1000 "PAR" is 100.. Think there is much difference in growth between 1000 and 900 PAR?
Some crops maybe, some not so much.

Cannabis is a LIGHT HOG and can take par far exceeding what other plants could tolerate in the long run.
Even then probably splitting hairs.

Compare Grow Room Wall Coverings: Mylar vs. White Paint vs. Vinyl GrowWall™

BTW: Don't agree with his numbers as to Mylar and paint but the text is interesting..

PET films are "mylar"
Keep in mind it is an advertising blurb.. 





						Reflectance vs Wavelength
					

plastic microfiber technology creates highly reflective and diffuse reflection over full visible spectrum; eliminates hot spots and creates an even, efficient distribution of light on plants in gardeners hydroponic grow room. Yield increasing product outperforms metalized foil products like...



					www.orcagrowfilm.com
				





> The chart below demonstrates the reflectance vs. wavelength performance of several popular brands and materials used in hydroponic grow rooms.   Metalized Polyethylene Terephthalate Film was first developed by DuPont in the 1950's; originally branded as Mylar, it is now commonly known as PET film and manufactured all over the world. Many products in the hydroponic industry are associated with false or misleading performance claims, and this is true of reflective films. PET film products are marketed to hydroponic consumers with performance claims as high as 99% reflectivity, despite historically testing in the low to upper 80% reflectance range in the visible spectrum.(More)










BTW: ORCA is white..





						wholesale hydroponic garden products
					

New yield increasing microfiber reflective technology for hydroponic gardeners and grow rooms outperforms mylar, foylon, poly film and metalized foils from easygrow.



					www.orcagrowfilm.com


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## oreo57 (31 Mar 2022)

Oh oh I missed something important. The paint chart above looks to be relative to spectralon NOT actual light spectrum.
Bonehead move on my part . Fortunately it only means 100% is 99% which is why Ba alone can archive the impossible of > 100% reflection. Adjust accordingly  `





Lastly about MIRO Silver reflectors..


			(Wfsites) - Page Not Found
		

Addendum. 86-90% is the reflectance of TiO2 in white paint


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## PARAGUAY (31 Mar 2022)

Going back to @eminor  picture with those lights looks strong enough


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## eminor (31 Mar 2022)

PARAGUAY said:


> Going back to @eminor  picture with those lights looks strong enough


thanks guys, i wasn't expecting that much information, i think i'm entering the rabbit hole with not enough light. tuberculatum might drive me crazy haha.

Clive would tell me to keep focus on co2, even with good diffusion, levels (drop checker yellow) tuberculatum seems to need tons of light

Maybe i'll let the reflector like that but i think it's not the most effective, or perhaps i'll upgrade with hydro reflectors as suggested above


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## PARAGUAY (31 Mar 2022)

Often just 2t5s on a high energy system is enough to grow any plant.


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## Hanuman (31 Mar 2022)

eminor said:


> i'll upgrade with hydro reflectors as suggested above


In all honesty I don't think you need to. Seems more like an excuse to spend more money but it won't solve your issue with Myriophyllum tuberculatum unless your tank is super tall. What's the size of that tank?


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## eminor (31 Mar 2022)

Hanuman said:


> In all honesty I don't think you need to. Seems more like an excuse to spend more money but it won't solve your issue with Myriophyllum tuberculatum unless your tank is super tall. What's the size of that tank?


60*30*30

Light : 2 * t5 HO, 24 watts, bulb 1 : sylvania 830 14w (overdrive), bulb 2 ; Amtra (wave) special plant pink 24w, the fixture is on the top of the tank


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## eminor (31 Mar 2022)

PARAGUAY said:


> Often just 2t5s on a high energy system is enough to grow any plant.


Maybe i need to work better to avoid shadow, that plant seems to won't allow shadow


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## Hanuman (31 Mar 2022)

eminor said:


> 60*30*30
> 
> Light : 2 * t5 HO, 24 watts, bulb 1 : sylvania 830 14w (overdrive), bulb 2 ; Amtra (wave) special plant pink 24w, the fixture is on the top of the tank


That seems more than plenty  considering your tank is 30cm high.


eminor said:


> Maybe i need to work better to avoid shadow, that plant seems to won't allow shadow


Yes more like it. Plant it somewhere straight under the light where no other plants will shaddow it. It should grow fast. I have to trim mine weekly. It grows ~15/20cm in a week.


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## ian_m (31 Mar 2022)

I have these on my T5 tubes. 
T5 Reflectors – iQuatics

In my use, the advantages are scale from hardwater doesn't stick and  when the reflective bit degrades you can just buy new inserts.

Before I used quite expensive aluminium reflectors, but suffered from scale severely reducing efficiency and slow but sure changing from super shiny aluminium to misty/brown/frosted metal reflector. Really really obvious in light levels when I changed from old aluminium to the iQuatics ones.


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## oreo57 (31 Mar 2022)

LOL should have started with size.  12" deep tank w/ volume est of 15 gallons shouldn' t have a light issue w/ 100 watts of light  regardless of reflector efficiency.
As to Myro, I' ve grown it like a weed and also killed it easily



> It is not an easy plant to cultivate. The M. Tuberculatum needs intensive light of at least 0.8 watts per liter, and high levels of CO2 injection. Nitrates should be kept to between 5 - 15 mg/l, and phosphates to between 1 - 2 mg/l. If either of these main nutrients falls below zero, the plant’s growth will be severely stunted. The species also need plenty of iron and micronutrients to reach its full size and color, or else it will end up as a dark and small plant


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## eminor (31 Mar 2022)

oreo57 said:


> LOL should have started with size.  12" deep tank w/ volume est of 15 gallons shouldn' t have a light issue w/ 100 watts of light  regardless of reflector efficiency.
> As to Myro, I' ve grown it like a weed and also killed it easily


Sorry i'm French, i still have some issue to understand english sometimes, you mean that even without reflector, i have more than enought light due to the small height of the tank ?


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## oreo57 (31 Mar 2022)

eminor said:


> Sorry i'm French, i still have some issue to understand english sometimes, you mean that even without reflector, i have more than enought light due to the small height of the tank ?


Even with your current reflector you should have more than enough light.
2 x 39w Odyssea par values (36" fixture)
10.5" (26 cm)130 91 92 85
16" (41cm) - 86 53 63 59.








						PAR values for Odyssea 36" 2x39W T5HO
					

Formatted as Height in inches followed by par values at the given locations. Done in air.  Height - center, sides, center front, center back 10.5   -    130     91           92             85 16      -     86     53           63              59 20      -     51      35          49...




					www.plantedtank.net
				



Not apples to apples comparison but it paints a picture.
Measured in free air.
I assume light face to surface.


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## eminor (31 Mar 2022)

oreo57 said:


> Even with your current reflector you should have more than enough light.
> 2 x 39w Odyssea par values (36" fixture)
> 10.5" (26 cm)130 91 92 85
> 16" (41cm) - 86 53 63 59.
> ...


thx, in air which means in the water there is way less Par, because light have hard time to get though it right ?


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## oreo57 (1 Apr 2022)

No.

2 things though.
1) water and stuff in it starts absorbing the red end if the spectrum. So water will absorb some light in the red spectrum but not much at 12"

2) Due to internal glass reflections and light refraction generally par will be higher than measured in free air where its "spread" is not restricted .


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