555nm for day / ???nm for night

• Sep 14, 2007

• #1

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Kwizatz_Haderach

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I've seen posts on how the human eye shifts its sensitivity to the blue end of the color spectrum at night. While 555nm is the "holy grail" wavelength, many of us use lasers at night for better visibility.

Anyone know the exact wavelength that the eye acquires best when dark adapted or have a link to a chart?

Thanks, Kwiz

 

• Sep 14, 2007

• #2

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Tallaxo

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Photopic vision (or daylight vision) has a peak frequency response of 555nm. Scotopic vision however, (night or dark adapted vision) Shifts its frequency further into the blue region of the spectrum and peaks at 507nm.

Here is a little graph to explain.

Jase.

 

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• Sep 14, 2007

• #3

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Kwizatz_Haderach

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Ah. That's what I was looking for.

thanks.

 

• Sep 15, 2007

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Daedal

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** Wishes he had a variable frequency laser... : **

--DDL

 

• Sep 15, 2007

• #5

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steve001

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Daedal said:

** Wishes he had a variable frequency laser... : **

--DDL

Click to expand...

Methinks you misunderstand. Photopic and Scotopic sensitivity occur under ambient lighting. If you were to compare two lasers with the same power output, but of 555 and 507 nm the green laser would appear the brighter of the two even at night