Originally Posted by wbassett
If true I agree, that would be incredible. Especially with the nice wide viewing cone SILVER has... to have that wide of a viewing cone and if the gain really was 3.0-4.0 that would be amazing.
Just out of curiosity (and not an uproar) but how did you come to the estimated value of 3.0-4.0? We measured SILVER to have a gain of around 1.36, so it would be fair to round up to 1.4
Don't get me wrong and go off or anything, 1.3-1.4 is a very respectable gain, especially with DIY. I just had to jump in though because I don't know how you came up with 3.0-4.0. If it was a guestimate by eye, that's understandable but also shows how much our eyes can fool us and aren't an accurate way of determining things like this or even color balance... but not to worry, SILVER doesn't have a bad color balance either. It's not dead on D65 neutral, but also isn't out of the range of good screen, especially for a lighter shade screen.
It was indeed an estimate, made by a couple individuals in attendence who have enough practical experience to venture such a determination without being too far off the mark. But as stated, it was an estimate, made by consiering the size screen, and the PJ's luminosity output and throw. What really thew everyone for a loop was two things....how bright and effective the huge thing was under ambient light, and how considerably wide the viewing cone was despite the apparent high gain. A lot of head scratching went on....I'll tell you that !
I do see where you mentioned the 1.4 gain value but stated an opinion that the screen wasn't made correctly or validated as being correct. All the directions were followed so it really should be representative of the typical results others will get. Of course you are right when you state if a different substrate is used or different base, it could affect the gain, but it isn't going to be that big of a difference, not a 2.6 increase in gain.
No, I didn't say it wasn't made correctly, only that I could not validate how it was made and if the measured gain was truly representitive of the application's potential. I didn't dispute the figures obtained either, only that they could only represent that particular effort, and therein should not be offered up as being definative of all such S-I-L-V-E-R s Some efforts, like the one above could be considerably higher in gain, while others might not make it much over 1.0
And really, that makes sense because in DIY, things are bound to vary to some little or large degree. In the tested example for instance, if the Screen was made exactly correct, (...most likely was...) and a gain of 1.4 was measured, that in and of itself is an accomplishment when accompanied by such a wide viewing cone.
I do beleive the reason the viewing cone is so good is that the properties inherent in the multi-layered translucent Glaze coats work to scatter a good deal of light comining from off the reflective particles, all the while as those particles are also directing a perponderence of light directly forward. Sort of the same thing as Light Fusion, but with the effect all contained within the Surface instead of coming from a complete penetration of light through the paint, and the subsiquent mirrored reflection and re-fusing of attenuated light with the original image. The latter helps maintain gain, the former (S-I-L-V-E-R) does far more to actually increase gain.
And in review, I did state that instead of using the 95% Glaze - 5% Silver Metallic formula, I had upped the SM ratio to 10%. I also did a heavier coating (IE: A MORE DENSLY PACKED AMOUNT OF SM THROUGHOUT, BUT ESPECIALLY NEARER THE SURFACE)
than a normal S-I-L-V-E-R would receive, knowing that the incomong light would not be nearly as high in level as normally encountered. Both would serve to increase the normally realized Gain potential S-I-L-V-E-R would usually provide.
All of that factored into the estimate that was made. And it was an estimate that in no way should be construed to being applicable to a normally configured S-I-L-V-E-R.
I hope that helps to quantify my previous remarks
Originally Posted by nirvy111
Someone who has done a quality S-I-L-V-E-R screen needs to get a sample of the Dalite High Power and compare. Providing the projector is positioned correctly it will tell you instantly which has the higher gain. That's what I'm interested in, more so than the actual measurement.
Well, that is eactly what was done, and the results reported. However at the time....and still in the present....it seemed a bit "risky" to hearld such news as being completely precise, so we simply moved the figure downward to to 1.8 range. The subsiquent test being refered to above came up with 1.4 gain.
So in fact, the explination I gave above does in some ways relate to the more normal version of S-I-L-V-E-R used in the "comparison" test. Viewed directly from the front, S-I-L-V-E-R was completely comprable to the HP. Viewed from the side at a point where the gain from the HP dropped of considerably, much more so than the S-I-L-V-E-R , it seemed to point out that the S-I-L-V-E-R must in the very least be producing the same amount of gain, if in fact actually more if the common formula of Drop-off percentage was considered.
So all of that presented a quandry...and mystery of sorts. And being so mysteriously unexplainable, it seemed wise to embrace a much lower figure that while still high, was more in keeping with conventional wisdom and acceptable levels.
As many others, I must await precise gain figures on the above screen. But in the same respect....it's a "One Off" example, so what it represents is potential, not conventional and normal results.
....but at least we all know it shows pretty clearly what CAN be done, and that is something exceedingly exciting of note. A quick post note made after I posted and then read Harpmaker's own missive;
I'm just too slow on the Draw being so slow on the Keys. While I slowly respond to wbasset's reply, (almost 90 minutes of stroking keys) Harpmaker has said almost the same things I was trying to relate....only in shorter verse. Once again, my "Hunt & Peck" efforts have come up lagging in the race to post up in a timely manner.
Yet another post script;
Originally Posted by Harpmaker
The problem is that these two screens work in totally opposite ways so in real-world situations there can be no fair comparison in relation to gain. The High Power is retro-reflective (light is reflected back toward the source) and the S-I-L-V-E-R screen is specular reflective (light is reflected away from the source).
Actually, and as related in my comments, S-I-L-V-E-R seems to be both screens rolled (...well, sprayed really...) into one, and do both things at the same time. Hence the quandry as to how to measure and accurately describe what is going on with the crazy thing.
Anyone who knows my typing speed knows I simply could not compose all of the above in the time frame shown after Harp's own posting and my own. It's flat out impossible!
Crikey! It took me almost 20 minutes just to type my two Post Scripts!