The Truth About Interactive Whiteboards and Active Screen Area

White Paper
The Truth About
Interactive Whiteboards
and Active Screen Area
The way you measure matters
This white paper is for informational purposes only, is subject to change
without notice and should not be construed as offering any future product
commitments on the part of SMART Technologies Inc. While significant
effort has been made to ensure the accuracy of the information, SMART
Technologies Inc. assumes no responsibility or liability for any errors,
omissions or inaccuracies contained herein.
© 2007 SMART Technologies Inc. All rights reserved. SMART Board,
AirLiner, the SMART logo and smarttech are trademarks or registered
trademarks of SMART Technologies Inc. in the U.S. and/or other
countries. All other third-party product and company names may be the
trademarks of their respective owners.
The Truth
and Active
Screen Area
Making sense of screen size
One of the most common interactive whiteboard ∗ specifications is screen
size, which is usually measured on the diagonal, i.e., the measurement
tells you the distance from one of the top corners to the opposite bottom
corner. Interest in this particular specification is high because people
believe it tells them how much usable whiteboarding space an interactive
whiteboard offers. They may not be aware, however, that the method of
measuring usable whiteboarding space can vary from one interactive
whiteboard manufacturer to another.
Virtually all interactive whiteboard manufacturers provide a diagonal
screen-size measurement, but not all of them mean the same thing by it.
For example, some manufacturers include an outside bezel in their
measurement, while some do not. Some will also indicate the height and
width of their board, excluding the bezel, but the diagonal measurement
will include the bezel. Some manufacturers will include height, width and
diagonal measurements, but the board may not be wholly interactive, in
which case usable whiteboarding space would be less than the
measurements suggest. When comparing screen-size specifications
from different manufacturers, it is important, then, to understand the
precise meaning of the measurement.
Inactive areas versus active areas
At SMART, with sixteen years of interactive whiteboard user testing and
research experience, we have consistently found that people really want
to know how much usable whiteboarding
space they will have. Over the years, we
Aspect ratio refers to the
have adopted a standard measurement,
ratio of an image's width to
active screen area, which tells users
its height. A 4:3 aspect
precisely how much whiteboarding space
ratio means that the image
they will get. On a SMART Board™
width is 1.33 times the
interactive whiteboard, for instance, active
screen area is synonymous with actual
height. It is a simple ratio
screen size. That means that the
based on the Pythagorean
projected image fills the entire screen,
Theorem a2 + b2 = c2.
right up to the edge of the bezel, and the
entire screen is interactive.
This way of defining active screen area is straightforward, but not
everyone takes the same approach. Some manufacturers design boards
that do not strictly take into account standard 4:3 projector aspect ratios,
This white paper discusses only front-projection interactive whiteboards. SMART offers a variety of
rear-projection interactive whiteboards. For more information, visit
The Truth
and Active
Screen Area
which then creates difficulties when defining active screen area. For
example, a screen that measures 78.8" (200.2 cm) on the diagonal must
measure 64" (155.4 cm) across and 46" (116.6 cm) high (excluding the
bezel in all measurements) in order for a standard 4:3 projector image to
fill the screen to the edge of the bezel.
However, some interactive whiteboards limit where on the screen the
image can be projected, i.e., the whole screen is not interactive. In these
cases, there may be corner markers on the screen indicating which part
of the board is interactive – usually the area inside the markers. With
these boards, the active screen area would be smaller than the diagonal
measure suggests because a small frame of inactive space exists at the
outer edges of the screen. It is also important to take into account the
aspect ratio of the projection area within the corner markers. If the area
is not 4:3, then the image may not fill the space properly.
Still other manufacturers include the bezel or an icon strip in their
measurements, which means the specification is not necessarily
measuring active screen area. Some include the bezel in width and
height measurements but not in the diagonal measurement. In all cases,
it is best to ask what is being measured and how.
The Truth
and Active
Screen Area
The final measure
When choosing the best interactive whiteboard for your needs, it is
important to consider the different ways that active screen area is
calculated. Ask exactly what a diagonal measurement includes. Although
one interactive whiteboard's measurement on the diagonal may suggest
you are getting more whiteboarding space than another's, that may not
be the case. Also ask if the aspect ratio of the board or projection area is
4:3 so you know whether a standard projected image will properly fit the
space. Be wary of 4:3 boards whose screen measurements contain
inactive areas; if they do, aspect ratio may be secondary, and you may
have less whiteboarding space than you think.
SMART has been designing and providing interactive whiteboards since
1991 – longer than any other interactive whiteboard manufacturer in the
world. It has installed more interactive whiteboards in more countries
than all other manufacturers combined. Part of that success comes from
having a strong team of research scientists and engineers who, in the
design of our products, ensures our interactive whiteboards work with
standards being set in the industry and with the other technologies that
work with our products, such as computers and projectors.
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