Originally posted by MSwauger
If you used an actual mirror, do you feel the result would be better than the Plexi back-coated with SM?
I ask this because I have a large (3ftx3ft) piece of "safety mirror" (mirrorized plexiglas) that I purchased for another project. This is not any heavier than normal and as I recall, it was not much more expensive than Plexi either.
Since reading CMRA's earlier results with his Plexi screen I have wondered if my Plexi Mirror would make a good substrate, but also wondered if it would be "too" reflective. Any and all thoughts would be appreciated.
here's the thought.
Mirrors offer their own reflective depth. They bend light, as well as transpose the image.
Only a "First surface" mirror would be appropriate. Your Plexi mirror is not among that company.
The use of the Silver metallic on the backside of Plexi is a way to achieve a more neutral degree of reflectivity. Let me clarify that. The SM reflects the light that reaches it as directly back as possible, and is not hindered by the depth of material it must pass the reflected light back through (1/8' plexi) the Top Coat is translucent enough to allow a good deal of the light to pass through, react to the properties inherent in the Silver Metallic's finish.
Since there is effectively no lag time between when the light hits the Top Coat, passes through to contact the SM, and then reflects back through the Top Coat to join up with light that did NOT pass through, the combination creates the final image you see.
Light comes in various wavelengths, all with their own specific properties, some of which will react to the Silver, some of which will react to the white in the Top Coat. hence, the reason for the creation of a multi layered finish.
The added effect that the ultra clear transitional boarder that the Plexi affords seems to create a depth of field akin to a perfectly layed down multi layer car finish. Done properly, such a finish reflects light almost as good as any mirror. but who can afford a 8 to 12 layer Finish on their Auto? Not many.
Nor can one apply that many layers of Latex without creating a opaque finish. When using the SM/Top Coat method on a single sided surface, care must be taken not to overload the top coat to the point that the SM's reflectivity is grossly reduced. Some reduction is essential, and in keeping with that, the mix is designed to be as translucent as possible, while still maintaining enough white pigment to help enhance the brightness and color uniformity of the lighter colors of the spectrum. The SM is primarily there for contrast enhancement, and the 'metallic' aspect is there to offset the dampening effect Grey hues have on most lighter colors.
the sum total should be a screen that reflects as much light as directly back to the viewer as possible, yet not so much as to wash out the detail that the varying levels of greyscale bring to an image. Contour cannot be achieved if there is no subtle shadows, and without shadow our world would be decidedly two dimensional.
Which is why the Plexi scheme is so incredible. The slight additional depth afforded by the 1/8" Plexi, combined with the reflective/enhancing properties of the Silver and Top Coat work together to create the very best blending of Contrast and Screen brightness I personally have ever experienced. Anywhere. It's like there was a light bulb 'behind' the screen. (CRT, that is.) And at the cost involved, no one in the Screen industry with an ounce of honesty could ever say that it isn't the most affordable way to "eat their lunch".
The highest gain screens available all come as a one piece unit, no matter how big. They do not/cannot be flexible or roll up & down. That should tell you that to achieve what they do, they must have a constantly stable platform to layer on their reflective material. They also must employ a slight curvature to reject ambient light coming from the sides.
yadda, yaddya, yaddya. let 'em eat light.
So don't bother with a mirror application unless you have the right mirror. Oh, you can certainly experiment with the mirror you have, but be advised that all you going to get is mediocre results for you efforts.
Better still, don't waste paint on a effort that is less than it could/should be. even a 3' x 3' foot surface will gobble up money better spent on paint for a know value.