Flatscreens vs Projectors
Ever since Ben Franklin trashed his 12 inch black-and white TV
in favor of a shiny new color VGA monitor, classroom technology has run towards
the ever-receding caboose of the display size and resolution train. At USU, we
have enjoyed the chase, taking advantage of falling prices and increasing
display sizes to stretch our AV budget, often favoring flatscreens over
projectors as the price to size ratio of these displays seemed to be following
its own Moore’s Law.
Where resolution, size and viewing distance were
appropriate, flatscreens could offer a better value. Superior brightness,
contrast ratio, viewing angle, ease of installation, and lower maintenance
costs made them an excellent choice for smaller classrooms and conference rooms.
We have always been conscious of sizing displays correctly for the needs of the
space and the intended use. Using a visual acuity calculator and specs based on
SMPTE standards provided us a reference point to design our spaces for the best
student experience. Now, the new Infocomm/ANSI standard - ANSI/INFOCOMM
V202.01:2016, Display Image Size for 2D Content in
Audiovisual Systems provides greater accuracy for image sizing
based on the intended use.
More Resolution and bigger TV’s
Simple calculations can provide a helpful guide, and can
show the optimum viewing distance for displays of varying sizes and resolutions
even without doing the additional calculations in the Infocomm standard. We
assume in most classrooms that the intended use will often require what the
Infocomm standard refers to as ‘Analytical Decision Making’ which suggests among
other things, high resolution. Typically in our usage cases this resolution is
1080p since that is the native resolution of common display technologies we
purchase, and until the advent of consumer 4k TV’s the best we could do with
the available budget. Consumer 4k TV’s are now available to us at roughly the
same cost we would purchase a 1080p set only a year or so ago, also, just try
and find a good quality 1080p LED TV. Freight-car loads have been left corroding
on that rail siding, a couple of miles back.
Is 4k necessary?
New 4K displays often have better contrast and color
performance than their now-sidelined 1080p siblings. Unfortunately, 4k
resolution itself is not especially useful in a typical classroom. The optimal
viewing distance for a 75 inch 1080p image is around 10 feet. At any distance
greater than this, a person with 20/20 vision will not see the full benefit of
this resolution. For a 2160p image om the same size display, the optimal
viewing distance is inside 5 feet. TV’s larger than 85 inches become costly. Affordable
4k projection will obviously make much larger image sizes possible, even so our
largest recent installation was a 208 inch screen. At around 15 feet wide and 8
and a half feet high, full benefit of 2160p would only be visible to a viewer
closer than 13 and a half feet, whereas our 1080p installation’s full
resolution is usable to nearly 30 feet.
A well-designed 1080p-capable system will likely continue to
provide us with the most usable images in our classrooms for a while.
Improvements in contrast ratio and color will make our classrooms better, but higher
resolutions, whether 4k, 8k, or beyond will not make much difference.
Until we can install eye upgrades…
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