Types of Screen Goo coatings
There are thirteen different types of GOO coatings, each with different specs and gain characteristics, grouped into three categories: Basic, Classic and Premium. They are:
Ultra Max Contrast
Ultra Silver 3D
Reference White +20
High Contrast +20
Max Contrast +20
Ultra Max Contrast +20
High Extinction 3D
Please refer to table below for gain characteristics and projector requirements (p.s.f) of screen area of all GOO coatings:-
- GOO is a performing paint, so to know which coating is most suited to your project, a number of technical considerations need to be taken in: projector specs, throw distance, light conditions, type of content. The AV Professional can advise.
- A GOO coating is chosen based on specs and site requirements, not its colour. GOO specifications need to be considered in conjunction with variables within the set up and what the site presents.
- With some exceptions, GOO can be rolled OR sprayed on. More
- All GOO coatings, except for those in Basic range and Rear Projection, work in and are applied in pairs, i.e. two parts: a reflective coat goes on first, followed by a diffusive coat – in this order.
- BASIC range is good for price and time sensitive, build-&-tear-down projects and/or internal viewings. One-part coating. Completion time half that of Classic and Premium +20 coatings.
- CLASSIC range is where Screen GOO started; and remain the most popular. They meet public viewing standards. It is the sweet spot in terms of performance versus price. Two-part coating.
- PREMIUM +20 range have 20 – 30% higher reflectivity than CLASSIC coatings. They are for the very demanding projects, where public viewing is very critical and budget no object. Two-part coating.
- REAR PROJECTION, or commonly known as RP, works on its own, NOT in a pair, and is to be sprayed on only. It works best in low light and was not made to compete with direct sunlight. For the image to be seen on BOTH sides, RP is applied on glass OR acrylic (Plexiglas), clear OR tinted. It will render the surface translucent.
GOO’s Reflective & Diffusive coats
Unlike ordinary wall paint which involves the application of a single product, a Screen GOO application consists of two different products: the reflective basecoat that provides an ideal reflective surface (for optimal light return) to which a diffusive, color correct topcoat is added (for excellent image uniformity).
It is the combination of the reflective basecoat and the diffusive topcoat which gives a Screen GOO screen its remarkable qualities of high reflectivity, color accuracy, wide viewing angles and excellent contrast. The icing on the cake is the very special sense of image depth, or feeling of looking into the picture that only a Screen GOO screen provides.
Features of a GOO screen include:
- Exceptional colour fidelity
- Excellent gain with minimal hot spotting
- Industry-leading horizontal and vertical off-axis characteristics
- Exceptional affordability
- Extremely wide viewing angle
- No colour shift
- Colour accurate screen structure
- Depth and dimensionality
Let’s get a bit more technical – what is ‘contrast’?
One of the key properties of high quality projected video is contrast. Contrast is defined as the difference between the brightest and darkest portions of an image.
The latest generations of digital projectors have very little difficulty in producing high levels of brightness. However, the darker areas of an image, specifically black areas, are a different matter entirely. Black is defined as the absence of light. Any light in a room, even light produced by the projector and reflected from the room's wall and ceilings, will compromise the accurate reproduction of black.
By using a neutral grey reflective surface, or screen, the levels of incidental or unwanted light can be significantly reduced without affecting color accuracy and overly compromising image brightness. Less unwanted reflected light means better black levels, which in turn means enhanced contrast. Unless the viewing room is completely light controlled, including dark, non-reflective walls and ceiling, a grey screen will always provide better black levels and higher contrast than a white screen.
Screen Goo is available in shades corresponding to steps on the D6500 Kelvin Grey Scale for optimal color fidelity and contrast.
Let’s get a bit more technical – what is projection screen ‘Gain’?
Gain is a measurement of the reflectivity of any screen or projection surface. The gain number represents a ratio of the light reflected from the screen as compared to the light reflected from a standard white board. A screen with 1.0 gain will reflect the same amount of light as that from a white board. A screen with 1.5 gain will reflect 50% more light as that from a white board. A screen with a 0.95 gain will reflect 95% of the light from a white board.
How is ‘gain’ measured?
It is measured from the vantage point; where the screen is at its brightest, directly in front and perpendicular to the screen. Peak Gain is at 0 deg. viewing axis. Half Gain is at 50 deg. viewing axis.
High Gain Vs Low Gain
There is a trade-off between gain and viewing angle. Seating can be placed in a wide viewing angle with a low gain screen, affording a similar viewing experience. Optimum seating is limited with a high gain screen, close to or at the center.
Off center, brightness diminishes or shifts dramatically. Low gain screens have wider half gain viewing angles than high gain screens. Low gain screens diffuses light more evenly over a wider angle of view. High gain screens reflect more of the projector’s light energy back toward the centerline of the projection path; and less light energy to the oblique angles of view.
Brightness falls off more rapidly as you move away from the 0 deg. viewing axis, and the half gain viewing angle is relatively narrow. A high gain screen does not typically reflect red, green and blue equally – image looks different from different angles. Screens with a gain higher than 1 have some degree of hot spotting. Low gain screens are favored when contrast and image quality need to be optimized.
The principle behind GOO’s Ultra Silver 3D (US 3D) coating
Screen Goo Ultra Silver 3D is a specially formulated coating designed to be used in the creation of non-depolarizing viewing surfaces for 3D projection applications. While there are a number of different technologies employed for displaying 3D film and video content, polarized 3D projection is emerging as the favourite of the feature film industry.
The principle of polarized 3D projection is straightforward: two slightly different images, each intended to be seen by one eye only are projected in opposite polarity. The viewer wears a pair of glasses containing two oppositely polarized filters -one for the left and one for the right eye. The oppositely polarized light from each of two projected images can only pass through its corresponding filter, ensuring that only the correct content is seen by each eye.