Tuesday, June 4, 2019

How bright is that screen? And how good a light is it?

I have always wanted a "fishtank VR" fake window that is bright enough to light a room.   Everytime a new brighter screen comes out I want to know whether it is bright enough.

Apple just announced a boss 6K screen.   But what caught my eye was this:

"...and can maintain 1,000 nits of full-screen brightness indefinitely."

That is very bright compared to most screens (though not all-- the SIM2 sells one that is about 5X that but it's a small market device at present).   How bright is 1000 nits?

First, let's get some comparisons.   "Nits" is a measure of luminance, which is an objective approximation to "how bright is that".   A good measure if I want a VR window is sky brightness.  Wikipedia has an excellent page on this I grab this table from:




Note that the Apple monitor is almost at the cloudy day luminance (and the SIM2 is at the clear sky luminance).   So we are very close!

Now as a light source one could read by, the *size* of the screen matters.   Both the Apple monitor and the SIM2 monitor are about half a meter in area.   How many *lumens* is the screen?   This is how we measure light bulbs.

This 100 Watt EQ bulb is 1600 lumens.   So that is a decent target for a screen to read by.   So how do we convert a screen of a certain area with a luminance to lumens?   As graphics people let's remember that for a diffuse emitter we know wsomething about luminous exitance (luminous flux):

luminance = luminous exitance  divided by (Pi times Area)

So 1000 = E / (0.5*PI) = E/6 (about).

E is lumens per square meter.   So we want lumens = E*A = 0.5*E = 1000.   So lumens = 2000.   That is about a 100 watt bulb.   So I think you could read by this Apple screen if it's as close as you would keep a reading lamp.   If one of you buys one, let me know if I am right or if I am off by 10X (or whatever) which would not surprise me!




2 comments:

Clipping Path Service said...

Lovely blog. Thanks for sharing with us.This is so useful.
clipping path service
clipping path

Lilly Ann said...

This information is nice... Thanks for sharing with us.