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Originally Posted by Kaptain K
Since I sorta started this, I guess I should (attempt to) clarify some what. I did not mean that a laser at any frequency the eye is responsive to could be seen as red or blue or green, depending on the single cone it was focussed on. The unspoken given was that it was in the range where the sensitivities overlap.
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Thaks for the clarification.
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Originally Posted by man on the moon
It takes time, 3-10 minutes for basic, functional night vision, up to 3 hours for the full amount. As far as I know, rods are not sensitive to color, but are highly sensitive to contrast. The book mentions that as well, though it was published in...I want to say 2003. Do you have a newer reference George?
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In one sense, I suppose, rods can be said to be sensitive to color; but rods alone do not produce enough information to allow a specific color to be rendered. Rods are most sensitive to green with a peak of ~510 nm, and they work within a color range between over 400nm to under 600nm. But, in the scotopic range, the brain has no way to know the spectral energy distribution of the light source as it is only getting one signal, so to speak.
However, in the mesopic range (between the rod-only scotopic and the cone-only photopic ranges), both rods and cones are working together. Since the cones have a net sensitivity peak of 555nm, then there is a bit of a blueshift when light intensities reduce to the level within the mesopic range. This color shift is known as the Purkinje effect. Objects will look more green or blue than they normally would. Or, said another way, objects will look less yellow, orange, or red.
The way I see it, in the mesopic range, it could be argued that we have 4 color receptors since all three cones and rods are still active signal generators for our color processing. [Dr. Lamb coined the term "retinex" to address the combined effect of our eyes with our brain's color rendering process.]
This is not an area I know much about, admittedly, which is why I was curious about
Kaptain K's laser circumstance.