Brightness at the source is the same - but light falls off by the square of the
distance. It is fainter and fainter.
So there is a safe distance - but it is dependent on so many variables.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



Leo Lichtman wrote:
"Les" wrote : Is there any rule of thumb on how close I can be and still
safely watch (not a casual glance) arc welding without any eye protection?
(clip)
^^^^^^^^^^^^^^^^
The eye is just like a camera--the farther away the smaller the image, but
the brightness stays the same. By standing farther away, you are damaging a
smaller area on the retina. How large an image are you willing to damage?



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