I agree Mike, and as you pointed out earlier, the LEDs are very directional so any direct reflective material is not going to have as noticable of an effect. And as I pointed out, anyone with a multi-tiered layout would certainly want to have the underside of the upper deck(s) painted for good appearance anyway. The OP asked which was the best "amplifier" which is what raised the controversy over mirrored surface vs. white paint.
Randy stated it the best:
"The foil, at least as long as it is not all crinkled up, is the better reflector. But the white paint is a better diffuser."
I had quite a few 48" two-tube fluorescent fixtures mounted in some soffits. The 60hZ hum used to annoy me something awful. After trying several types of electronic ballasts, which still hummed to some degree, I ripped them out and re-wired the fixtures for LED tubes. No ballasts. The 115 hot and neutral wire to each side of the "tombstone" lampholder.
BUT the tubes only direct light about 120° in the direction away from the fixture. I had fixed several reflective devices to try to redirect the light to where I needed it but in the end I wound up having to remount each fixture and turn them 90° to point down.
http://www.amazon.com/gp/product/B00O1CJC0C?psc=1&redirect=true&ref_=oh_aui_detailpage_o09_s00
Ed
gmpullmanLamp manufacturers developed the inside frosted bulb to help diffuse the light for a more pleasing appearance. GE even developed the "Reader" lamp that had additional diffusion.
This is the sort of reflectivity most likely of use beneath an upper deck and why there's no real advantage in using a highly reflective material vs white paint. What you're dealing with is diffuse light in most cases.
Mike Lehman
Urbana, IL
This chart may shed some LIGHT on the subject
The "A" in the PAR lamp stands for aluminized as in Parabolic Alumimnized Reflector or PAR lamp.
There must be a reason a mirror finish was preferred for various flood lights, headlights and spotlights.
I remember as a kid using a piece of mirror to reflect sunlight and it sure worked better than a square of white paper...
Now the "properties" of the reflected light as in concentrated or diffused are ultimately what makes for a pleasing atmosphere or a harsh environment.
Lamp manufacturers developed the inside frosted bulb to help diffuse the light for a more pleasing appearance. GE even developed the "Reader" lamp that had additional diffusion.
So what you may want to consider is a combination of highly reflective materials (closer to the light source) to get the light directed to where you want it and softer white materials surrounding the source to diffuse and disperse that light.
Have Fun, Ed
Lone Wolf and Santa FeElectrical contractors who get big $ contracts lighting indoor gardens use Mylar on the walls.
I have yet to run into a job that contemplates Mylar being applied to walls. Considering that phrase "big $", perhaps I should find some.
I am surprised that the electrical contractors would take a contract that would include applying Mylar to walls. They are also, then, taking the responsibility if the Mylar application fails. But they got the job, and I didn't, so they must be doing it the right way.
Since the Mylar is being used in a project for lighting indoor gardens, I wonder if it has reflectivity in more appropriate frequencies than other materials. Interesting.
I was a journeyman electrician for too many years.
Me, I'm still pluggin' along (nyuk, nyuk, nyuk).
7j43k Lone Wolf and Santa Fe Electricians use Mylar to reflect light instead of aluminum foil. I've been an electrician for 40 years and I don't. There may, indeed, be other electricians that do. So I would recommend preceding the word "electricans" with a modifier like "some" or "a few" or even "many". This, of course, after doing a proper statistical sampling of the class. For most of the work I do, I install the light fixtures exactly as specified by the manufacturer, customer, designer and/or the general contractor. And, let's not forget the opinion(s) of the electrical inspector. That way, I don't have to hear how "my" method was inadequate/improper. If the person writing the check were ever to specify Mylar, I'd likely put it in. I am VERY interested in and responsive to the person who writes the checks. I am NOT a lighting designer. I am an electrician. Electrical contractor, actually. On those rare occasions when I offer an opinion (at home, for one), I recommend flat white titanium dioxide paint as a reflective surface. I'll note that aluminum foil is conductive, if that is or will become a concern to you. Ed
Lone Wolf and Santa Fe Electricians use Mylar to reflect light instead of aluminum foil.
Electricians use Mylar to reflect light instead of aluminum foil.
I've been an electrician for 40 years and I don't. There may, indeed, be other electricians that do. So I would recommend preceding the word "electricans" with a modifier like "some" or "a few" or even "many". This, of course, after doing a proper statistical sampling of the class.
For most of the work I do, I install the light fixtures exactly as specified by the manufacturer, customer, designer and/or the general contractor. And, let's not forget the opinion(s) of the electrical inspector. That way, I don't have to hear how "my" method was inadequate/improper. If the person writing the check were ever to specify Mylar, I'd likely put it in. I am VERY interested in and responsive to the person who writes the checks.
I am NOT a lighting designer. I am an electrician. Electrical contractor, actually.
On those rare occasions when I offer an opinion (at home, for one), I recommend flat white titanium dioxide paint as a reflective surface. I'll note that aluminum foil is conductive, if that is or will become a concern to you.
All right let me rephrase: Aluminum foil is not used by the electricial industry as a reflector. I don't think it passes UL. Lighting manufacturers use Mylar as a reflector in many styles of light fixtures which electricians or their helpers install including styles of lights which are found in every home, like your hall light. Many times it has fiberglass insulation on the back and a couple of screw holes in the middle and a hole for the wire. Other times it is in an exterior fixture and doesn’t need insulation, like a quartz or sodium fixture. Right now I am looking at a 16” black light fixture and I can clearly see the Mylar reflector right behind the tube.
I'm not suggesting that you do anything other than install the fixture.
Electrical contractors who get big $ contracts lighting indoor gardens use Mylar on the walls.
Gotta remember that the light we're trying to reflect under benchwork is coming from a variety of direction, if your lights are pointed at your scenery and then bouncing around from there. In a theater setting, the light is projected colinear (at least I think that's the word my rusty physics is reaching for) -- all parallel in one direction.
Very different results and goals in those 2 distinct applications. The special paint will definitely be an advantage in a theater setting, not so much under the layout.
7j43kThat said, that is not how reflective paint works. The paint contains (usually) tiny glass microbeads:
Yep, right after I clicked submit I remembered the product you were talking about. You responded too quickly before I could retract.
The DA-Lite screen I had in my home theater was not made this way. It was actually gray instead of white. The thinking was that a highly reflective white screen limited your ability to reproduce the blacks in the image.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Carl, in the previous post, asserted that I was wrong and that reflective paint would do its reflecting as a mirror would, and that the angle of incidence would equal the angle of reflection.
My response:
I recall that lesson from high school physics. And I recall the lesson in college physics that explained that event even better and more subtly*.
That said, that is not how reflective paint works. The paint contains (usually) tiny glass microbeads:
Notice how the light is reflected back along the line it came in on.
That's why, when you shine a flashlight at reflective stripes on railroad rolling stock, you see a dramatic glow from the reflective paint. The light is being reflected back to its source, with very llttle being dispersed.
The same idea has been used for projector screens. The last one I bought (many years ago) proudly said that it had reflective glass beads in/on it. The idea is that people sit very near the projector. So the light is returned in that direction. That also means the screen will appear very dark from the sides. But who every sits there????
Hence my statement that the reflective paint will return the light towards where it was emitted.
* This conversation reminded me about that "update" in college about the incidence and reflective angles being equal. When we think about that "bouncing" event, we think about it as if a ball was hitting a wall. Or a pool ball hitting the edge of the table. And we all know that the incoming and outgoing angles are the same. And we all know the same holds for light hitting a highly polished metal surface. But where the "basic" theory fails is that the polished metal surface is almost totally empty space (you know, various particles and such going about their business). So there's really almost nothing there to reflect photons. They really should mostly just zoom on through the metal, with only a few hitting anything. And even when they hit a "thing", why would they happen to hit it "just right" and bounce off at the approved angle?
Anyway, I was treated to a beautiful explanation of how it works. Well, until someone learns even more about teeny little thingys.
deleted
Reflective paint (and I think that would likely include projector screen paint) is designed to reflect the light back from whence it came.
So the bright lad who uses it will be reflecting light back to the light source. Is that REALLY what you want?
Well, maybe, if price is no object. I'm reminded of the Drive By Trucker's line that goes something like "don't get caught with a bucket of rich man's paint..."
I'm sure it's better stuff than the $15/gallon stuff at the big box. However, I'd almost bet in the cheap seats you'd get 90% of the effect the $95/gallon stuff gives you and then you could put the $80 saved against your next loco.
What someone ought to do is repackage that expensive stuff for MRR use. I can think of several uses for it on a much smaller -- and more affordable -- scale. Painting road markings, a drive-in theater screen, road signs, certain conspicuity markings, etc.
For painting unseen benchwork, I personally would go with the cheap stuff. YMMV
Projector screen paint:
http://www.amazon.com/Projector-Screen-Paint-Definition-Ultra/dp/B00DR7E7Z2
Good learnings on this thread for sure!
I'm reminded of the opposite scenario where as "no light" is desired - most typically on the open ceilings of bars and restaurants where everything is painted flat black.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
High reflective white paint:
https://www.sherwin-williams.com/homeowners/color/find-and-explore-colors/paint-colors-by-family/SW7757-high-reflective-white/#/7757/?s=coordinatingColors&p=PS0
Take Care!
Frank
Using white paint that is used for movie screens would work great.
If you saw the underside of the deck above on my layout, you'd realize how hopeless I'd be if I tried Mylar.
The thing about white paint is that once dry, it's forever outta the way. You can work around it or add stuff without any issues. Foil and Mylar both share the characteristic of being in the way of virtually anything, not to mention the hassle of figuring out how to support them to actually gain the best use.
My assessment is that, assuming there is some slight reflective advantage with foil or mylar, it is more than offset by all their negatives versus the ease of slapping paint on to dry and being done with it.
One thing I've found helpful on lower decks is aluminum duct tape, the kind that has the peel off backing leaving aluminum foil with adhesive on one side. I have flourescents down there right now. From certain angles their light would spill in your face. I peeled back enough of the AL tape to stick and made little hoods or visors for ones like that. It's flexible and can be pushed out of the way as needed, then you can straighten when done.
Mylar would increase the brightness the most. Electricians use Mylar to reflect light instead of aluminum foil. Another choice is reflective white paint, specially formulated to be bright. The difference is paint will diffuse the light source removing hot spots, however it is not as bright and can be a big mess.
Keep in mind that if you have the LEDs oriented right, they produce a very directional light. Any reflection from behind the lamp(s) is incidental and reflected already. The advice to simply paint everything white is probably going to gain more than foil would, because it tends to reflect light arriving from a variety of angles. To best use foil, it needs to be flat, as Randy, Jim, and others advised, but that assumes it's bouncing light that generally arrives from one direction. You lose that advanatge when the light has already been reflected once and is scattering. White benchwork would tend to deal with that better.
As a scientist I have to first point out that neither white paint or aluminum can amplify light, that would require adding energy into the mix to amplify it. Amplification basically means to "increase, or make more intense".
Randy rightly specified that foil would make the best "reflector" because it is behaving more like a mirror and most of the spectrum from the light source would be bounced or reflected back to the scenes of interest. The problem with foil it is is an imperfect reflector and the more deformed or crinkled is, the more it will be bouncing the light at many angles, and you won't get it reflected in the direction you need it, and because of that, you loose some of the light away from where you want it.
White paint tends to reflect light better than other colors because it basically reflects all of the spectrum it bounces off of more other colors, which absorb some of the spectrum and only reflect some of it, depending on the color. Therefore, it is a good reflector vs. colors which do not reflect most of the spectrum; this is why we paint rooms white if we want them to be "brighter" vs. other colors. Still, it is second to something that reflects all of the light and energy but as mentioned above, that is not the only consideration. You also want a diffuse pattern to your light so that it is distributted more evenly on the scene.
I am considering getting some 4' fluorescent style LED light bulbs, which come in clear and frosted. The clear version would probably provide a bit more in raw light or lumens, but I personally prefer the frosted because it diffuses the light, and it is less attention getting than the many points of light versions. I've noticed this in Mikes Rio Grande narrow gauge layout when he posts photo's where you can see above - the many points of light effect is distracting to me, so I think I will prefer something which diffuses the light.
Rio Grande. The Action Road - Focus 1977-1983
I worked in a model shop in New York back in the 1970-1980 period and we always used white for our reflective surfaces on flourescent light fixtures as it was more reflective than the polished chrome/ss ones. I always use white now when I want a good reflective background for LED's. The alum foil will still work but I would take the white over the foil on my layout.
BTW, I have used the foil you show and it does stick quite well and is reflective, but it assumes the finish qualities of the surface it is mounted to (very thin). I tried it on the sides of my Santa Fe F7 to simulate the ss surfaces and it works quite well.
-Bob
Life is what happens while you are making other plans!
The foil, at least as long as it is not all crinkled up, is the better reflector. But the white paint is a better diffuser. Since you'd never have the foil perfectly smooth, I think the effect would be one of reflecting many points of light, exaggerating the tendency of a string of LEDs on the tape reels to already do this. You'll lose more light relfecting oof a white painted surface, but the reflections will also not be as sharp, making the light look more like a continuous source.
I used to have tons of tape like that, for some reason my grandfather used to bring rolls home from work when I was a kid (he was NOT in HVAC work!). I used it everywhere, though it has no real strength. Mostly for things liek holding down aluminum foil, since it slosely matched in color - I made a robot costume with lights, a Star Trek transporter console, bunch of things. One thing with tape like that, eventually the adhesive dries out and it starts coming loose. So as Mobileman said, for longevity reasons as well as the reflective qualities, go with the white paint.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Some time back I had some recessed lighting (kitchen & two baths) updated and the contractor suggested painting the inside of the "boxes" with ceiling white paint. I did just that, and the result was obvious.
For your situation, I would tend to paint vs using foil. I have no major reason for saying that, but there are some minor ones that do - ease of painting, longevity of the painting, no concern of metalic foil around electrical circuitry, and overall appearance.
I use a product similar to this:
http://www.homedepot.com/p/Nashua-Tape-1-89-in-x-50-yd-322-Multi-Purpose-HVAC-Foil-Tape-1207792/100030120
I can not verify which of several brands I have but it is handy for passenger car roof interiors, structure ceilings, diesel headlight shielding and, yes, it reflects LED strip lighting very well.
Once it is stuck, it is on for good so plan out your installation and just peel back enough backing to tack it in place before you make it permanent.
Lots less messy than paint and very reflective. But you would probably still want to paint the underside of your upper deck anyway wouldn't you?
At least that's what works for me...