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The last screen I built was artist canvas with CRT White Goo. It was sprayed using a Wagner Power Painter and I ended up with a gain of around 1.3. I noticed on the Goo website the gain for CRT white is specified at 1.8. Has anyone been able to verify this? How does it compare against a sample of the Stewart Videomatte for example?


I need a new screen and was leaning toward the Videomatte for the extra gain. If the Goo is truely 1.8 then I may consider another DIY screen. I'm a little skeptical since my previous experience puts it at a gain of 1.3
 

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The 1.8 gain level we have published is due to the fact that the 'video industry standard' method of measurement is NOT used.


Our product does not react favorably with that method. It has some very decidedly 'strange' behavior, in comparison to 'standard' screen products..


For example, most screen products rely very heavily on 'direct reflection' of light to get their gain numbers and overall image.


Our products are very, very diffuse and diffracting in how they handle light.

Screen Goo Topcoats and Basecoats are overall, a combination of Diffusion, Diffraction, Color Correction, and Retro-Reflection. All fine tuned over a 4 year period of experimentation. All done without pigmentation or loss of color vibrancy across the entire visible light range.


On that note, we can easily challenge the 'Reference' for white screens in studio use with Goo Systems CRT White, in any court, or any venue. Any time, any where, any eyes, and any measurements, period. It is -truly- a reference product.. without peer.



The industry standard places a light source at 30 degrees off the perpendicular and then the light measurement device at 30 degrees off the perpendicular, on the other side of the center or perpendicular. This gives a light source--measurement device total screen angle of 60 degrees.


In essence....in the industry standard method of gain measurement ... the so-called ON AXIS measurement is actually at a incident angle of 60 degrees!!!!!!!!!! It is almost totally a surface reflection method. Tisk-tisk!


There are many companies and people who are behind us in the idea of changing this 'self created' video industry measurement method.


A given high reflectivity screen surface will give the same measurement no matter where the sensor or the light source are placed, as long as the light source is exactly shot at the light sensor, via reflection. This shows that the screen relies heavily on 'surface reflectivity'.. and not optical properties associated with the substrates and/or any "coatings". How advanced or difficult is that to create? Not very. Paint me unimpressed.


Our products measure dramatically differently, depending on the angle of the sensor to the light source. This is why the sensor is placed on the perpendicular and the light source on the same perpendicular..as close is as possible, which results in a difference of a minor few degrees. Barely measurable difference, if at all measurable. By this method, we get a 'peak' gain of 1.8. The light output drop off as you head out to the corners, or if you are off axis to the screen..is so low.. it is virtually un-noticeable to the human eye.


If we use the 'Video industry standard method', we get a considerably lower gain measurement ..like 1.3 or so. Maybe less. So, yes, we don't rely on simple surface reflectivity in our products or their overall design. Any one can create a simple screen that does that.


Our technology is quite a bit more advanced.


If you use a simple reflective screen and it looks fine to you, well.. great! It works for you and that is all good! But.. when you use a surface that has low change in output across a large viewing angle..it brings a lower change in light as you move across a given visible image..and that alone creates a much richer gamut of color for the human eye...total eye candy. There is that to watch out for in high gain reflective screens. CR in a given scene is damaged by the brightness change across the screen itself, due to the high reliance on surface reflectivity!!


You see, the iris of the eye will dilate or contract according to the average light it receives, and that will not be uniform across the scene..from the light that enters the eye..on a high reflectivity screen. Therefore, fidelity is lost..across the given 'captured' (in the eye) scene. The light is not uniformly bright, in that one observed part of the image or scene!.


The max you can go to, is a gain of about 1.5, in a reflective screen. After that the degradation of image is noticeable. The only cure for that is a curved screen, when using high reflectivity surfaces, to regain brightness uniformity.


Goo Systems products are riding 'just below' that maximum 'perceived' level of gain change, and purposely so. To maintain image fidelity, in all parameters, with the least amount of compromise overall, in all areas.


Do you see what I mean?
 
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