Colour vision

[Lightning Phil]

Yes, a shade of green, whereas ao and midori are, AIUI, separate colours. If you say something's emerald and I say it's jade, we can argue over this but both agree it's green of some sort. Whereas if something's ao, it can't be midori. AIUI...

But artichoke can’t be Emerald even though both shades of green 😁

[Diver300]

Bi-colour^[1] LEDs are a work of Stan.
_{[1] Two LEDs in one housing, giving three possible colours, depending on which are switched on.}

I came across a bi-directional LED with two red LEDs in one housing. However the purpose was to allow it to illuminate with either direction of current, and the difference wasn't supposed to be noticable, so it's probably going to be allowed into Kim's box of electronic bits.

I noticed the slight change in illumination angle between the two LEDs.

[FifeingEejit]

Few younger people, of course, realise that the world was monochrome till 1973 when they first debuted beige, the first ever colour (at the time a lot people thought that colours wouldn't catch on) but it took the early 70s by storm. It was so popular that they followed it with orange in 1975 and red a year later. An experimental blue was first sighted in the wild in 1982, though quite a few people believe that was an inadvertent release from the labs. The precise debut of green is still debated even today. Of course, once released, colours rapidly started to breed.

Beige?
This was sold as Gold

[Asterix, the former Gaul.]

Assuming there's anyone on the internet who isn't familiar with The Dress, it's worth checking out. It reveals a lot about how we model colour perception.

Colour is very complicated. Colours themselves can be pigmental (i.e a pigment that absorbs and reflects certain frequencies) or structural* (a physical refraction or diffraction of incident light). The two can interact (so stripy things can be perceived as different colours). It'll all depend on that incident light (which is why things are different colours under sodium lamps). The receptor pigments in your eyes have varying frequency responses curves.

*this explains blue/green/grey eyes. Humans, and all mammals, only have two** pigments – black-brown eumelanin and red-brown pheomelanin. There's no actual blue in blue eyes.

**slight lie, we have another, near-black neuromelanin, which as the name suggests is present in the brain, hence the substantia nigra.

Me. I'd never heard of that pic.  On my screen it's clearly a photo showing a gold/white dress.  That's twice removed from reality since it a camera image shown on a VDU.   

And I know I am not colour blind because I used to work for the railways.

[ian]

It's a blue and black dress. The point is that it's a photo, if you saw the dress in person, it would be blue and black but robbed of contextual information in the photo, your brain fills in the contextual gaps with assumptions, so a lot of people see a white and gold dress.

[Asterix, the former Gaul.]

It's a blue and black dress. The point is that it's a photo, if you saw the dress in person, it would be blue and black but robbed of contextual information in the photo, your brain fills in the contextual gaps with assumptions, so a lot of people see a white and gold dress.

Yes, I noted it was removed from reality.  As are too many of my own photos.   

[hellymedic]

My colour vision (well really just my right eye now, post optic neuritis) is pretty good, though my Dad is red-green colour blind.

I get the feeling that for ME colours have an instant emotional effect - a slightly orange yellow is happy and sunny, red stands out anywhere, pale blue is cool. I probably notice colour before I notice other aspects of things. I suspect other women may be similar.

Desaturated colours are calmer and duller.

I appreciate others perceive differently.

[sojournermike]

Resurrecting an old thread, but older daughter has just mentioned these spectral cut lenses to help improve colour discrimination for red-green colour blind people.

https://enchroma.co.uk/collections/colour-blind-glasses?gclid=CjwKCAjwue6hBhBVEiwA9YTx8BcXPf2jPegB4FJc9NnkG9Xu9EDdUCRcI7s9mOnX_3PAVRa0ApVZWxoCyWIQAvD_BwE

Thought this was interesting- anyone here tried these or anything similar? Do they help?

I suspect there is a range of responses.

Mike

[Kim]

The £BloodyHellHowMuch-factor is offputting...

[Rod Marton]

Yes. I use something similar, and they do help. Though don't expect miracles.

Mine date from the eighties, when I was taking part in some colour vision research, and the researcher mentioned that colour discrimination could be improved by using selective filters. So then it was down to a friendly optician, a set of stock filters and the Ishihara test, and finding which worked best. The one that did improved my colour vision from appalling to poor, but even that is definitely an improvement.

Ever since then I have colour-matched the filter when getting a new set of glasses, and whilst I suspect there has been a bit of drift over the years and my glasses aren't as effective as they used to be, they are still better than my colour vision without.

[sojournermike]

The £BloodyHellHowMuch-factor is offputting...

Yep, H did say, ‘but they are very expensive’ - before commenting on my immediate search for how they work!!

[sojournermike]

Yes. I use something similar, and they do help. Though don't expect miracles.

Mine date from the eighties, when I was taking part in some colour vision research, and the researcher mentioned that colour discrimination could be improved by using selective filters. So then it was down to a friendly optician, a set of stock filters and the Ishihara test, and finding which worked best. The one that did improved my colour vision from appalling to poor, but even that is definitely an improvement.

Ever since then I have colour-matched the filter when getting a new set of glasses, and whilst I suspect there has been a bit of drift over the years and my glasses aren't as effective as they used to be, they are still better than my colour vision without.

That’s interesting. I have normal colour vision as far as I can tell - albeit my left eye is distinctly yellow compared to my right eye (which has a new lens courtesy of the cataract surgery required as a consequence of the retinal repair…). That’s aging. I also now have a -9 prescription for the left and 0 for the right!

[PeteB99]

I looked at them about 10 or so years back and rapidly ran into the bloodyhellhowmuch factor. I decided against them on the grounds that having got to a reasonably advanced age with my current vision I'm not sure how much I'd want to change to a completely new vision (though it would be nice to try it).

The other problem with enchroma seems to be that they are in effect fairly heavy duty sunglasses and thus little use indoors and at night when their capabilities might be most useful.