Reflecta Projection Screens - Manual (Page 6)

B A S I C S
SCREEN KNOW-HOW
Basics about the fabrics
If you want to present pictures or information to
an audience, be it in the private or business
sector, a perfect presentation is indispensable.
However, this can be achieved only if projec-
tion device and screen match each other. A slide
projector, e.g., needs a different screen than a
beamer. Before purchasing a screen, you should
therefore think carefully about the intended pur-
pose.
In the private sector, different factors are
decisive than when used in the business world.
When used at home, the pure pleasure of wat-
ching the presentation is in the foreground; when
the screen is not required, it should be hidden
unobtrusively. In the business area, a stable
design to withstand daily use and versatile appli-
cations is required.
Basics about brightness
In order to view a projected picture, the picture
must have a certain brightness. This brightness,
of course, depends on the light in the room, and
the picture must be brighter than the surroun-
ding light. It is also clear that in bright rooms,
the pictures must be proportionately brighter
than in dark rooms.
A decisive parameter of all projectors is their
light intensity. For multimedia projectors, this
intensity is measured in lumen, where the stan-
dard of the American National Standard Institute
(ANSI) is applied frequently.
The larger the projection surface, the lower
the amount of light per surface unit since projec-
tors – irrespective of the size of a picture –
always produce the same amount of light.
part from light intensity, the contrast value is
an essential factor which influences the quality of
the projected image. The contrast value indicates
the ability of a projector to reflect a scale of sha-
des as wide as possible in their colour intensity
from the darkest to the brightest shade as in real
life. A high contrast will produce a natural, vivid
image.
Hence, luminous efficacy and contrast value
must match the brightness of the ambient light
and the characteristics of the projection screen
to produce a perfect image.
The ratio between the brightness of the pro-
jector and that of the projected image should be
5:1 as a minimum to achieve the best image qua-
lity.
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