Re: My eye sensitivity to blue-violet higher than normal
I can tell you what I've heard, without any particular authority, although my wife does have blue eyes, if that helps.toggle quoted messageShow quoted text
1) during WWII, the navy used ultraviolet lights (long wave) to illuminate phosphors on the decks of carriers. Some few could see the lights, they invariably had blue eyes. Apparently, people with blue eyes don't have a pigment that can block UV.
(ELK can see in the UV spectrum. Wolves on snow blend in under normal light, when looked at under UV light, the wolves stand out.)
2) there is sufficient chromatic abberation in the human eye that blue and red focus at different distances. Find a red/blue LED display, and you'll see that the blue seems to be more distant. Human vision is optimized for forest light, a rather yellowish green.
3) judging from the phosphors in the normal light fluorescent lamps, I'd guess that the different phosphors (more blue part, look and it seems to be yellow and blue) have different persistence, with blue being shorter than yellow.
Some things to think about:
1) you're probably more sensitive to nighttime glare, the ones from the hopped up trucks with the low beams (if not high) that are almost blue in color. A suggestion is to wear yellow tinted glasses.
2) as you get older, perhaps with cataracts, blue light scatters more, and will increase your sensitivity to glare.
3) it's easier to deal with blue sensitive photo film. There's more energy in blue light, and the film can be handled under red light (dim, mind you). Photographic paper is primarily blue sensitive if it's B&W. (Orthochromatic). There are orthochromatic (blue sensitive) and panchromatic films. Panchromatic films need to be handled under total darkness or the dimmest green (light sensitivity of the human eye) filter available. Orthochromatic (Kodak fine grain positive release film, or kodalith, for instance) are safe under dim red light.
4) P11 phosphors were designed to match blue sensitive film, have a *very* short persistence for recording high speed events, and when viewed, will flicker a lot more.
Note that the normal phosphors are really in the yellow/green spectrum, with various persistences, so that they can be viewed under dim light. The orange phosphors in some radar tubes (P12), were designed for command deck use under night conditions, where all the lighting was red.
Humans have a chemical called rhodopisin, (sp?) which increases the sensitivity of the rods (monochrome sensors) in the eye. The center point of the eye has a lot of cones (color sensors) and not so much rods. As you go out from the center of vision, you start to run out of cones, and get more rods.
In terms of vision, you look at what's in your central vision and you get high resolution color. It's not a large high resolution area at all. As you start with peripheral vision (rods) you get light sensitivity, sensitivity to movement, but no color. Translation: SOMETHING IS TRYING TO SNEAK UP ON YOU, LOOK OVER HERE!!!
Since cones aren't very sensitive to light, they don't do well in the dark. Rhodopsin is a chemical that takes a bit of time, but increases the sensitivity of the rods to light. This is your "night vision". Rhodopsin is ionized (read: destroyed) by blue light. Blue light = no night vision, which is why astronomers use red light at night, and why ship's bridges are in red light when under night conditions.
Yet another reason why blue phosphors (P11) aren't used for low light level situations. The P7 phosphor uses a blue layer behind a yellow layer. The blue layer ultraviolet causes the yellow layer to glow with a long persistence. Normally, for night time and radar, these are used with orange or yellow filters.
That's the history as I know it.
On 5/23/2021 7:34 PM, Mark Vincent wrote:
I would like to know from anyone in this group that has a good educated to