Talk:Purkinje effect

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[edit] --hand off--?

What does --hand off-- mean? Surely that's not what it's meant to say. --193.60.223.228 08:20, 14 March 2006 (UTC)

I've changed hand off to transition. Hopefull that's what the author was trying to say. Maybe someone can check it to make sure. THanks for catching that! delldot | talk 17:30, 14 March 2006 (UTC)

[edit] Possible contradiction

In my opinion, the paragraph:

Incidentally, the same "lack of sensitivity to red" is why red lights are used in instrumentation panels: the red light does not disrupt the night vision (because the rods do not respond to it), and the fovea is largely L (red-sensitive) cones, hence they are easy to read.

is contradictory, because in scotopic vision (night vision) the rods (and not the cones) are active. So if you want to view a red panel, photopic vision (which is more focused to the fovea) would be more efficient. Of course, if luminance is very low this would not be possible.

In other words, as everyone can experience, night vision is more sensitive to blue colors than red colors (which is what the article says, in fact). So the sentence "hence they are easy to read" seems contradictory.

Possibly, there are other good reasons to use red lights. This one is not convincing to me. 83.58.184.146 19:17, 19 June 2007 (UTC)

I'll attempt to rewrite this section. Red lights are used at a reasonably high brightness level so that the good acuity of the cone system can be taken advantage of. Why not just turn the lights on completely then? Full spectrum light would saturate the rods. Dark adaptation requires about 20 minutes. So, if a crewman on a submarine were reading an instrument panel under full light, and then had to retrieve something from a dimly lit part of the sub, the crewman would be effectively blind for 15 or 20 minutes. By using red lights on the bridge of the sub, the crewman can read the instruments with high acuity without bleaching out the rods - so that he is dark adapted at all times. The eyes can then "take advantage" of the high acuity system and the high sensitivity system simultaneously. SJS1971 (talk) 14:32, 26 November 2007 (UTC)