[[Admin] PHugger]

All of these factors can be calculated - your consultant should have done this for you.

The required screen size can be determined with some degree of certainty. Screen size should not be left up to an opinion (it looks good).

Determine screen size
Measure the distance from the screen to the furthest seat in line-of-sight. If the majority of the content is video, divide that number (the distance) by 8. This will yield the screen height. Remember that this is just one of many possible formats that will determine which number to achieve the screen height.

Next, measure the distance from the screen to the closest audience seat that is in line-of-sight to that screen. The screen should be no taller than twice that distance. Example - 6' tall = 12' away for closest viewer. This isn’t always possible, but it is preferable. Remember, the furthest viewers take priority, as it is better for the screen to be “too big” for those close than “too small” for those in the back.

The screen height will be the same if the aspect ratio is 4:3 or 16:9 as only the width is different (if done correctly, anyway). This is not the same as “letterboxing” a 4:3 image, so make sure you’re either using 4:3 or 16:9 – not letterbox.

The projector lense can be determined as well

Using Ratios to Select the Correct LCD Lens
When using ratios to select a lens, you must consider the screen width and the projection distance to the screen. The formula is distance/width. For example, if you had a 10' wide screen and a projection distance of 10', you would require a lens with a 1:1 ratio. If your distance changed to 20', you would then require a lens with a 2:1 ratio. However, due to the different LCD panel sizes, the actual focal length of the required lens would be different for each panel size, even though the ratio would remain the same. See the chart HERE.

Finally the brightness (lumens) of your projector can also be determined

Determine square footage of the screen surface
Take the screen height (in feet) and multiply it by the screen width (in
feet). Ex. 6' x 8' = 48 sq. ft.

Multiply the square footage of the screen by 20 (ANSI says 18 + or – 2, so we use 20).
Example - 20 (ANSI lumens per sq. ft. minimum) multiplied by 48 (sq. ft.) = 960 projected lumens.

960 lumens isn’t hard to find in a projector by today’s standards. But before you get too excited, remember that ANSI specifies that 18 (+ or - 2) is the acceptable number. This is assuming NO light is hitting the screen. Pitch black area. Dark. No light. Nada.

Our next measurement is at the screen area itself - the amount of foot-candles of light striking the screen surface from lights, windows, etcetera using a light meter.

Let's assume we measure 8 foot-candles striking the screen surface. We now take our number ( and multiply it by 5 (our next formula). The answer? 40, of course.

That (40) is the number we must now reach to have adequate lumens being
projected onto the screen surface. In other words, we must project at least 40 lumens per square foot onto the screen to over come 8 foot candles of light on a 6’ x 8’ screen.

So, going back to our first example, we have 48 sq. ft. of screen area. We multiply 48 by the new 40 lumens per sq. ft. number to get 1,920 lumens.

Therefore, assuming no screen gain, we will need nearly 2,000 lumens projected onto the screen surface from the projector in order to overcome ambient light.

I agree with Glenn - go 16:9 if you can. Talk to your consultant about this.




Best regards,
PCH