Screen Gain
- Testing Acoustic Performance Factors
- Transmission Loss
- Smell / Off-Gassing
- Testing Visual Performance Factors
- Screen Gain
- Screen Gain - The Awkward Truth
- Screen Gain Data
- Surface Texture
- Light Bleed
- Welcome
- Image Surface Performance Factors
- Visual Performance Factors
- Acoustic Performance Factors
- Environmental Performance Factors
What is Screen Gain
Screen Gain is a simple parameter but all-powerful in the average comparison of image surfaces. This property, analogous to a speaker's sensitivity, is almost as valuable for describing image quality as sensitivity is for describing good sound!
Screen gain describes how efficiently the image surface reflects the projected light towards the user. A reflectance standard with a known, lab-calibrated efficiency is measured to determine a reference level brightness. When the brightness of the image surface is measured, it is divided by the reference brightness to calculate the gain.
Screen Gain = Image Surface Brightness / Reflectance Standard Brightness
How is Screen Gain Measured
Display Technologies uses a Spectralon reflectance standard with >99% efficiency across the visible light spectrum. This standard also has a set of calibration files to remove any production variance.
The projected and measured area must remain consistent during measurement runs to avoid inadvertently altering the light intensity rather than the image surface's performance.
Impacting Screen Gain
A higher screen gain value indicates more light reflecting off the image surface to the viewer. Gain is a linear property, so while higher gain makes the brightest parts of the image brighter, it also elevates the level of the darkest parts of the image, reducing contrast.
There are two ways to increase the gain of an image surface.
Use optical techniques to focus reflected light towards the viewer
Use reflective elements in the image surface to increase the overall reflectivity of the surface
Optical techniques can be very effective in increasing gain, and they were common in the days of 300-lumen CRT projectors. This solution has two adverse effects: increased surface texture and, more noticeably, a reduction in the viewing angle.
Adding reflective treatments can be effective in delivering a small increase; however, when used to excess, they introduce sparkles in the image—little pinpricks of brightness that are intensely distracting.
Image Surface Types
There are three main categories of image surfaces
PVC - Plastic-type surfaces can offer excellent flatness and are a base for more specialist optical or reflective processes. They can only be made AT through the use of micro-perforation
Fibreglass—Woven using fibreglass strands, these surface types offer excellent AT properties but usually have a much more visible texture due to the large diameter of the strands.
Polyester - Knitted with polyester strands, these surface types offer excellent AT and image properties based on their construction with very fine strands.