Re: how much of what we see is black?

From: Flick Harrison (email suppressed)
Date: Tue Oct 30 2007 - 13:28:03 PDT

Hate to be a splitter.

We don't actually "see" any blackness at all. From our point of
view, there is no blackness.

Aside from the witty comment on here that you can't see blackness (it
is the absence of an image, so it's more like not-seeing).

Persistence of Vision is the phenomena wherein your optic nerve (or
whatever) takes time to "reset" i.e. cool down and stop transmitting
the last image you saw.

Frame rates which create the optical illusion of continuous movement
are using this phenomena.

The image stays in your optic nerve while the shutter closes,
advances the frame, then re-opens just in time for your optic nerve
to absorb a new image.

Your eye / mind never notices the blackness because it's not fast
enough to see it.

I.o.w., your eye is fooled into thinking there is no darkness. The
darkness is too short for you eye's mechanism to register.

It;s not like the optical illusion of a bunch of dots becoming a
straight line as you pull back. That is simply perceptual / mental
illusion, at least until you get back so far that the dots fall below
the resolution of your eyeballs.

It's more like an optical override.

To be clear - continuous motion on screen is an optical illusion,
created by a series of still pictures. Continuous brightness on
screen is a neurological illusion, not an optical one - though that's
splitting optic nerve-hairs.


On 30-Oct-07, at 6:53 AM, Yoel Meranda wrote:

> A question I'm curious about...
> When a film projector is running, what is the percentage of time the
> light is interrupted by the shutter? In other words, what percentage
> of what we see is darkness?
> I realize that this question will have different answers for each
> projector...
> I am mostly curious about 35mm projectors but any clue on any other
> projector would be great. Even guesses would be fine if no one has
> concrete answers.
> Thanks,
> yoel
> __________________________________________________________________
> For info on FrameWorks, contact Pip Chodorov at <email suppressed>.

For info on FrameWorks, contact Pip Chodorov at <email suppressed>.