Pagina 10 - Projecta Catalogue 2014 EN

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Output (ANSI-lumen)
The brightness of a projector is
measured in ANSI-Lumen. The
higher the number of ANSI-Lumen,
the brighter the projected image and
the more it can compensate for
ambient light. Please note that a too
bright image is not pleasant to look
at for a longer period of time.
Projector position
A projector can be placed in front of
or behind a projection screen. The
projector can also be mounted on the
ceiling or placed at table height. A
projection surface has a specifically
designed coating that handles the
light that hits it, which makes it
necessary to pay attention to your
choice of projection surface type.
The specific lens of a projector
determines the distance between the
projector and the projection screen,
which is the throw distance. If a short
throw or ultra short throw lens is
being used it is important to use a
tensioned projection surface. Using a
short throw or ultra short throw lens
decreases the distance between the
projector and the projection screen.
This however also creates a situation
where the projected light reaches the
projection surface at an extreme
angle, which is why we recommend
using a tensioned projection surface
to avoid distortion of the image.
Gain is a measure of reflection performance.
Gain is related to a universal reference
standard: Magnesium Carbonate (MgCO3).
Rather than absorbing light, MgCO3 reflects
projected light back with perfect evenness.
Matte White, with a measured gain of 1.0, is
the standard brightness for a projection
screen surface.
The perceived amount of light that is
reflected by the projection screen is
expressed in LUX. The optimum image quality
and readability is achieved when the
projector’s light output, the size of the
projection screen and the gain characteristic
of the screen surface are all appropriately
matched to each other. This is achieved when
the ratio between de LUX value of the
projected image and the wall behind it is at
least 5 to 1.
As a general guideline, one can say that in
normal ambient light conditions, the
Viewing Angle
The viewing angle of a projection screen surface indicates the maximum angle at which the
projected image is still clearly visible. The brightness of the image decreases as the viewing
angle increases in relation to the axis of the image. The maximum viewing angle is the point
at which the viewer perceives less than 50% of the luminous intensity of the image. This limit
is the commonly accepted standard for image quality.
Black borders surrounding the projection area on a projection surface
increase the perceived contrast of the projected image. Because
Projecta’s objective is to satisfy the highest display image quality
standards, all of our projection screens are supplied with black
borders where this is technically feasible. Another benefit of borders
on a projection screen is to facilitate projector alignment.
Projector ANSI Lumen
Screen surface area in m
100 low ambient light levels
400 normal ambient light levels
X gain
background light output is approximately 80
LUX meaning that the quantity of light
that comes from the projection screen needs
to be about 400 LUX. In conditions of
low ambient light, the background LUX value
is about 20, meaning that the LUX value of
the screen needs to be about 100.