On 31-Jul-2004, wrote:

Considering you can see through aluminized Mylar, I have my doubts about this
claim.

Full sun is about 10,000 footcandles. We can see in 0.1 FC,
ie we can "see through" something that's 99.999% reflective.

I can see thru some aluminized mylar in a dimly lit room. My
guess is that these are no more than 50% reflective. High-
reflective aluminized mylar is harder to get and more expensive.
If you're going to recommend Al mylar, you have to be specific
about the quality and reflectivity.

My solar filter is nowhere near 99.999% reflective and I see
the sun thru it dim and safe. Don't forget that there is absorption.
My solar filter - nickel-steel coated glass - gets quite hot when
in the sun. The titanium-white painted mask around it doesn't.

It's a myth that mirror finishes (metallic coatings, polished
metal etc) are great reflectors of heat and light. Good quality
white paint can outdo mediocre mirror finishes easily and are
often a lot cheaper.

Mike