Originally Posted by TXFlyGuy
My screen is a "one off" design. Never tested. And that is the reason for the question on light meters / screen gain.
Now I and others are happy your happy, but the effort is hardly a "one off design" as any number (ie: 1000s) of White Screen variations have been made, a great many using Paints with sheen tempered with additional Flat or Matte Paints or Polyurethanes. Many, many using SW paints in fact. The application is almost as old as this Forum...and there are about several hundred Threads...and a lot of discourse about the merits of using exactly such combinations. What's Old is New again, but never tiresome...and is made all the more relevant by today's crop of mega-Contrast, Light Cannon Projectors. Before they arrived...Unity or .8-.9 Gain Greys ruled the day.
As mentioned before elsewhere, the Glidden / Diamond Bright White was adjudged the very best (Neutral) and highest Gain (1.3) of all the available White OTS Paints over 5-6 years ago. A solid reason why it figures in every advanced DIY paint formula I've advocated the last 5 years. Before that, it was a Tie between SW-Duration "Extra White" Matte, and Valspar Ultra White Flat Base A...both measured at 1.1 gain
To all of those, any number of Grey Tints and additional ingredients have been added. You know...like the old SS and many of the other ones you were also considering on another Thread.
Consideration should still be give to just what might have been discovered had any of the other well known, exceptional Whites been used. Suppositions on potential performance based on known values are fairly easy to conjure up...and still be pretty accurate.
What it really truly is is a 1st for you and understandably you want to know just how good it is. Will it's measured performance be wholly indicative of it's visual attributes you already have determined to be extremely good? It's the type of information that is always good to know....such tests have always been valuable when discussions come up, helping to sift the wheat from the chaff. Accuracy is paramount though...of course.
However...as good as it may be....and that may well be better than even you realize...it is and still remains a basic White Paint combination of two well known White Paints...sprayed as is always preferred, a combination that aspires to be a excellent, smooth white surface for Projection. No more....but certainly no less than.
But in the end, what you have "discovered" for yourself is all that matters. It's a damnable good feeling to realize you tinkered your way into something special...and telling others only helps make it all seem all the more special.