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Photometrics for Bounce (1 reply and 2 comments)

Brant
2 months ago
Brant 2 months ago

Hi Roger,

I've looked to no avail for this on the forums search, so apologies if it's been asked and answered.

Are there published photometrics somewhere for light loss when bouncing into, say bleached and/or unbleached muslin? Do you use a round figure if you need to plan what you need, if you do such calculating at all?

I'm guessing it's a 70% loss but I'm sure there are quite a few variables such as distance from bounce that could make this not really a linear thing. Best thing would be to go to the studio and test, but failing that, I wonder if you know of any figures for this somewhere.

Roger Deakins
2 months ago
Roger Deakins 2 months ago

I have never seen any charts related to bounce light. I suppose anything is possible but there are so many variables it might take a Big Blue computer to work it out.

Mark Wuerthner
2 months ago

This person did a test using various diffusions and bounce materials. He has some metrics related to both that you might find useful.
This person did a test that has some metrics in terms of bounce materials.
https://blog.mattporwoll.com/the-ultimate-diffusion-bounce-test/»

https://blog.mattporwoll.com/the-ultimate-diffusion-bounce-test/»

Brant
2 months ago

Thank you Mark, that link is terrific! I’m a little surprised to see such consistency across the different materials used. It would be interesting to see if a more powerful source would impact the extent of light loss, which is actually about 65% for the bounce, from what I can tell.

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