15 Jul '16 18:02>16 edits
In this wiki link;
https://en.wikipedia.org/wiki/Rod_cell
there is a diagram for the graph for wavelength responses for rod and cone cells;
https://en.wikipedia.org/wiki/Rod_cell#/media/File:Cone-response.svg
But I am confused by the left hand side of the shape of 3 of the 4 curves on that graph because the 3 for the rod cells and the green and red cone cells don't appear to tend towards the horizontal axis as you look leftward but appear to tend to some arbitrary none zero height above the horizontal axis and then mysteriously just suddenly discontinues at 400nm ! Why don't they show how the curve continuous beyond that point? And note it specifically says "wavelength responses" at the bottom of that graph, not merely what wavelengths the cells absorb irrespective of how they respond to those wavelengths.
Can anyone give an explanation?
Is the graph simply nonsense i.e. wrong?
Not only that, but the curve for the red cone cell responses, after peaking at 564nm, at you continuously move leftwards from that, after reaching a local minimum, it starts to rise again thus implying there are not one but two local maximums (the left one not shown; but why not!? ) to that curve which is supposed to be the response curve for those so there are not just one but TWO such wavelengths for max red cone cell responses? Does that make biological sense?
I suppose that doable local max to the red curve at least would explain why, as you go to the shorter wavelengths of blue, the blue starts to look violet as if you mix a dash of red to blue it makes it appear violet. But I find it strange that I have never heard of this as the explanation anywhere in my studies.
Also, according to that graph, the peak for blue cone cells is 420nm. But that doesn't match at all with what this link below says is its peak:
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html
"...The "blue" cones are identified by the peak of their light response curve at about 445 nm..."
I would say 420nm is way off 445nm -that's a 25nm difference that I don't see how we can ignore. Which link is right and which is wrong?
https://en.wikipedia.org/wiki/Rod_cell
there is a diagram for the graph for wavelength responses for rod and cone cells;
https://en.wikipedia.org/wiki/Rod_cell#/media/File:Cone-response.svg
But I am confused by the left hand side of the shape of 3 of the 4 curves on that graph because the 3 for the rod cells and the green and red cone cells don't appear to tend towards the horizontal axis as you look leftward but appear to tend to some arbitrary none zero height above the horizontal axis and then mysteriously just suddenly discontinues at 400nm ! Why don't they show how the curve continuous beyond that point? And note it specifically says "wavelength responses" at the bottom of that graph, not merely what wavelengths the cells absorb irrespective of how they respond to those wavelengths.
Can anyone give an explanation?
Is the graph simply nonsense i.e. wrong?
Not only that, but the curve for the red cone cell responses, after peaking at 564nm, at you continuously move leftwards from that, after reaching a local minimum, it starts to rise again thus implying there are not one but two local maximums (the left one not shown; but why not!? ) to that curve which is supposed to be the response curve for those so there are not just one but TWO such wavelengths for max red cone cell responses? Does that make biological sense?
I suppose that doable local max to the red curve at least would explain why, as you go to the shorter wavelengths of blue, the blue starts to look violet as if you mix a dash of red to blue it makes it appear violet. But I find it strange that I have never heard of this as the explanation anywhere in my studies.
Also, according to that graph, the peak for blue cone cells is 420nm. But that doesn't match at all with what this link below says is its peak:
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html
"...The "blue" cones are identified by the peak of their light response curve at about 445 nm..."
I would say 420nm is way off 445nm -that's a 25nm difference that I don't see how we can ignore. Which link is right and which is wrong?