Status
Not open for further replies.
1 - 3 of 3 Posts

#### Don Giberson

·
##### Registered
Joined
·
404 Posts
Discussion Starter · ·
Given the area and gain of a screen, what is the formula for calculating total lumens once you have a ft-Lambert reading? I found the following but am unclear with where to apply the values?

B = (k*E)(1/pi)

Bfl = k*E

where: B = luminance, candles/foot^2

Bfl = luminance, foot-Lamberts

k = reflectivity 0<k<1

E = illuminance in foot-candles (lumens/ foot^2)

#### luvmytivo

·
##### Registered
Joined
·
402 Posts
ft/lamberts = (pj lumens * screen gain)/screen area in square feet. If you know 3 of the variables, you can solve for the 4th - for example

pj lumens = (ft/lamberts * screen area in square feet)/screen gain (i think that's right... it's been 8 yeas since algebra)

------------------

Darren Rogers

I really mean it, you're starting to get on my nerves!

Listen, I'm not kidding here, if you keep reading, you're gonna regret it!

Look into my eyes, and do not doubt my reslove - if you persist, you will be taught a lesson you will not forget!

#### Phat Phreddy

·
##### Registered
Joined
·
6,227 Posts
Without wanting to divert this thread...

What would people estimate the screen gain (or lack of it) from blackout material vinyl side ?? It looks bright white and kind of reflective and I have been happy with it enough that for my el cheapo and temporary setting it does fine...

Just wanted to make some calculations...

------------------

[email protected]
HTPC without using windows... GUI Front Ends for Home Theater

1 - 3 of 3 Posts
Status
Not open for further replies.