Back to the IR light source concept...

In article ,
(Chris Hodges) wrote:

I modelled the blackbody curves in excel, and you're right, by quite a
margin - I don't know whether the power requirement or the IR output
would fall faster for a given emitter as you drop the temperature
(assuming temperature control for convenience) so it might not even
save battery life.

Nice to find out that the numbers match my world picture Seriously!
I was having a hard time swallowing the idea that IR output would
increase (in any way other than relative to the amount of visible light)
due to a voltage drop.

The maglite could be a good way to go - the focussing output would
seem to help, even if you have a diffuser effect from the vis blocking
filter.

Indeed. I'm thinking that no matter what the raw light source ends up
being, whether a "pure IR" source without filtering, or a filter system
in front of a visble source, it will be mandatory to have a
variable-focus beam.


Did you ever try multiple visible gel filters - these tend to be cheap
(I seem to remember ?10 (~$18)/sq foot), and for a maglite even
offcuts would be enough, so even cheaper if you have a friendly
theatrical/DJ supplies shop that does stage lighting.

That has been suggested, but at this point, I've done nothing with it.
At the very least, it seems to me that it would be worth trying.


I can have a look with a lamp and digital camera later. With anything
less than hundreds of watts they'll last forever.

Hmmm... maybe it's just me and my misinformation, but I've always been
under the impression that gels are the "cheap to buy this one, but
expensive as hell in the long term due to needing frequent replacement"
solution. My limited time "on the boards" (credited in the program as
"Soldier with a line" - chuckle) in a 6 week run of Jesus Christ
Superstar at a local playhouse showed me a lighting guy *CONSTANTLY*
griping about needing to chase up into the flys to replace gels -
sometimes before each run of the show, and particularly the reds. From
that, I reached the conclusion that gels are, at best, a "make-do",
rather than a permanent solution. And the prices... choke At one
point, I overheard him saying something like "There goes another hundred
bucks" while he was working on cutting a blue one to shape.

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