https://sci-hub.tw/https://doi.org/10.1111/ceo.13167

Does including colour‐blind men enhance search and rescue teams?

From Clinical and Experimental Ophthalmology.

They set out to find out if colourblind people were, as is often said, helpful in finding things in the bush. The answer turned out to be sort of. If you paired people, and one was colourblind and the other not, those pairs were best at finding things, when compared with colourblind/colourblind and normal/normal pairs. It’s a very small study – I think they were just curious really. But an interesting result.

Unexpected

they knew about it to find camouflaged

Apparently the military likes colourblind people for those sort of things.

Spiny Norman said:

Apparently the military likes colourblind people for those sort of things.

The ADF limits the roles in which colour-blind people can serve. There can be safety and operational risks in some roles.

I think you can be a rifleman in the Army with classification 3 c/b (significant deficiency), presumably based on the premise that c/b people can stop bullets as well as do non-c/b people.

ABC News:

‘Mark Zuckerberg says he understands “frustration” about how big tech companies are taxed in Europe, saying Facebook welcomes reform being undertaken by the OECD’

I understand that Google dodged paying a lot of tax in Britain by maintaining that it had’ no physical presence’ in the country.

As comedian Miles Jupp put it, i presume that this means that you can go to the Google offices at 76 Buckingham Palace Road London, 1–13 St Giles High St
London, and 6 Pancras Square London, and squat the ruddy shit out of them.

captain_spalding said:

ABC News:

‘Mark Zuckerberg says he understands “frustration” about how big tech companies are taxed in Europe, saying Facebook welcomes reform being undertaken by the OECD’

I understand that Google dodged paying a lot of tax in Britain by maintaining that it had’ no physical presence’ in the country.

As comedian Miles Jupp put it, i presume that this means that you can go to the Google offices at 76 Buckingham Palace Road London, 1–13 St Giles High St
London, and 6 Pancras Square London, and squat the ruddy shit out of them.

Wrong thread (sigh).

SCIENCE said:

they knew about it to find camouflaged

That is acknowledged in the introductory paragraph. It’s to do with pigments and light reflection and stuff.
Mostly with aerial photographs is my understanding. And also with black and white photos.

buffy said:

SCIENCE said:

they knew about it to find camouflaged

That is acknowledged in the introductory paragraph. It’s to do with pigments and light reflection and stuff.
Mostly with aerial photographs is my understanding. And also with black and white photos.

For me, “camouflage” stands out strongly – it is not camouflaged.

Michael V said:

buffy said:

SCIENCE said:

they knew about it to find camouflaged

That is acknowledged in the introductory paragraph. It’s to do with pigments and light reflection and stuff.
Mostly with aerial photographs is my understanding. And also with black and white photos.

For me, “camouflage” stands out strongly – it is not camouflaged.

Likewise.

But I think other things are more likely to influence search success: Patience, mental focus, technique, understanding the target, search design, and motivation all play important parts.

buffy said:

https://sci-hub.tw/https://doi.org/10.1111/ceo.13167

Does including colour‐blind men enhance search and rescue teams?

From Clinical and Experimental Ophthalmology.

They set out to find out if colourblind people were, as is often said, helpful in finding things in the bush. The answer turned out to be sort of. If you paired people, and one was colourblind and the other not, those pairs were best at finding things, when compared with colourblind/colourblind and normal/normal pairs. It’s a very small study – I think they were just curious really. But an interesting result.

Good. That makes perfect sense. As red-green colourblind (specifically deuteranomaly), every test I do (other than Ishihara) says that I’m always worse at distinguishing colours. But Ishihara says otherwise, and occasionally, as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

What I want to know is whether tetrachromats, women with one colourblind eye and one normal eye, are as good as pair of people one of whom is colourblind and one of whom isn’t, ie. whether tetrachromats are better at colour search than normal colour vision.

“Deuteranomaly, caused by a frequency shift in the green retinal receptors, is by far the most common type of colour vision deficiency, mildly affecting red–green hue discrimination in 5% of European males. It is hereditary and sex-linked. In contrast to deuteranopia, the green-sensitive cones are not missing but malfunctioning.”

> The ADF limits the roles in which colour-blind people can serve. There can be safety and operational risks in some roles.

Handling colour coding on fine electrical wires is more difficult but not impossible for colourblind people, as I found out when wiring up ancillary equipment for Hercules aircraft engine. I heard that’s one area where colourblind people aren’t allowed to serve.

People with my type of colourblindness see every colour on the following chart as distinctly different.

RGB is not a good way to distinguish colours for colourblind people, because that triangle misses a lot of the parabola of colour possible with pigments. But even so, there is a small region of RGB space where colourblind people distinguish colour detail much better than normal colour people. With real pigments, this region is much bigger. I refer to it as the yellow-green to blue-green axis. Very good for spotting changes in the colour of lush vegetation.

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

AFAIK I have normal colour eyesight. The Army tested me, took me in, fed me, trained me in electronics, and never once mentioned a deficiency or abnormality with my eyesight. For me the colour differences between the three mugs is blindingly (sic) obvious.

sibeen said:

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

AFAIK I have normal colour eyesight. The Army tested me, took me in, fed me, trained me in electronics, and never once mentioned a deficiency or abnormality with my eyesight. For me the colour differences between the three mugs is blindingly (sic) obvious.

+1.

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

Yes. Yes it is.

ChrispenEvan said:

sibeen said:

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

AFAIK I have normal colour eyesight. The Army tested me, took me in, fed me, trained me in electronics, and never once mentioned a deficiency or abnormality with my eyesight. For me the colour differences between the three mugs is blindingly (sic) obvious.

+1.

+ another. Although I’m suspicious I may be a carrier for deuteranomaly, and could therefore have a mosaic retina. I pass the normal colour vision tests, but when you get to the finer detail I’m a bit dodgy.

It’s possible if the mugs are in a dark cupboard the two greens may look more similar in mesopic vision.

buffy said:

ChrispenEvan said:

sibeen said:

AFAIK I have normal colour eyesight. The Army tested me, took me in, fed me, trained me in electronics, and never once mentioned a deficiency or abnormality with my eyesight. For me the colour differences between the three mugs is blindingly (sic) obvious.

+1.

+ another. Although I’m suspicious I may be a carrier for deuteranomaly, and could therefore have a mosaic retina. I pass the normal colour vision tests, but when you get to the finer detail I’m a bit dodgy.

It’s possible if the mugs are in a dark cupboard the two greens may look more similar in mesopic vision.

Anyway, they are all different colours for me as well.

Michael V said:

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

Yes. Yes it is.

Well in the picture the two green mugs are clearly different, but I wouldn’t say the middle one was anywhere near midway in colour.

How the actual mugs look in the ambient light of the actual cupboard, I don’t know, I haven’t seen them.

mollwollfumble said:

People with my type of colourblindness see every colour on the following chart as distinctly different.

RGB is not a good way to distinguish colours for colourblind people, because that triangle misses a lot of the parabola of colour possible with pigments. But even so, there is a small region of RGB space where colourblind people distinguish colour detail much better than normal colour people. With real pigments, this region is much bigger. I refer to it as the yellow-green to blue-green axis. Very good for spotting changes in the colour of lush vegetation.

So, at least in some cases, “colour-blindness” is not actually an inability to differentiate colours, it’s a shift in the bands were clear differences are visible?

The Rev Dodgson said:

mollwollfumble said:

People with my type of colourblindness see every colour on the following chart as distinctly different.

RGB is not a good way to distinguish colours for colourblind people, because that triangle misses a lot of the parabola of colour possible with pigments. But even so, there is a small region of RGB space where colourblind people distinguish colour detail much better than normal colour people. With real pigments, this region is much bigger. I refer to it as the yellow-green to blue-green axis. Very good for spotting changes in the colour of lush vegetation.

So, at least in some cases, “colour-blindness” is not actually an inability to differentiate colours, it’s a shift in the bands were clear differences are visible?

Not really. It’s more an insensitivity to some colours. Protan people have dull red perception. Protans used to be quite capable of not even seeing the red reflectors on the back of parked tray trucks, with fatal consequences sometimes. The colours of reflectors have been tweaked in the last 50 or so years. Deutans have desaturated greens. So a green light can look white. But to complicate matters, there are degrees of protan and deutan. A protanope is the worst case, very dull red. A protanomal (has protanomaly) has some red perception but it’s poorer than a full normal. A deutanope will see a green light as white, a deutanomal will perceive a washed out green.

Do you need the paper with the pictures of simulated protan and deutan put into this thread?

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1444-0938.2007.00135.x

Go down to the Advice to Patients section. Pictures show you how things look to colourblind people. They live in a dull sort of world. But it is normal for them. See how they have difficulty with telling when red meat is cooked. Look at the carpark pictures.

If you want a lot of technical stuff:

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1444-0938.2004.tb05056.x

sibeen said:

mollwollfumble said:

> as in the case of two green mugs in my kitchen cupboard, people with normal sight have a lot of difficulty telling them apart whereas the difference to me is blindingly obvious.

Picture included. To me, the colour of the middle mug is extremely different to that of the right hand mug. So different that its colour is almost midway between the colour at left and that at right.

AFAIK I have normal colour eyesight. The Army tested me, took me in, fed me, trained me in electronics, and never once mentioned a deficiency or abnormality with my eyesight. For me the colour differences between the three mugs is blindingly (sic) obvious.

Good! Thanks for the info. That shows that the RGB triple is not at all representing to full colour space. There has to be a big conversion error from true colour to rgb.

buffy said:

The Rev Dodgson said:

mollwollfumble said:

People with my type of colourblindness see every colour on the following chart as distinctly different.

RGB is not a good way to distinguish colours for colourblind people, because that triangle misses a lot of the parabola of colour possible with pigments. But even so, there is a small region of RGB space where colourblind people distinguish colour detail much better than normal colour people. With real pigments, this region is much bigger. I refer to it as the yellow-green to blue-green axis. Very good for spotting changes in the colour of lush vegetation.

So, at least in some cases, “colour-blindness” is not actually an inability to differentiate colours, it’s a shift in the bands were clear differences are visible?

Not really. It’s more an insensitivity to some colours. Protan people have dull red perception. Protans used to be quite capable of not even seeing the red reflectors on the back of parked tray trucks, with fatal consequences sometimes. The colours of reflectors have been tweaked in the last 50 or so years. Deutans have desaturated greens. So a green light can look white. But to complicate matters, there are degrees of protan and deutan. A protanope is the worst case, very dull red. A protanomal (has protanomaly) has some red perception but it’s poorer than a full normal. A deutanope will see a green light as white, a deutanomal will perceive a washed out green.

Do you need the paper with the pictures of simulated protan and deutan put into this thread?

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1444-0938.2007.00135.x

Go down to the Advice to Patients section. Pictures show you how things look to colourblind people. They live in a dull sort of world. But it is normal for them. See how they have difficulty with telling when red meat is cooked. Look at the carpark pictures.

If you want a lot of technical stuff:

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1444-0938.2004.tb05056.x

> A deutanope will see a green light as white, a deutanomal will perceive a washed out green.

To me as a a deutanomal, a green traffic light looks blue with a little bit of green added. The light looks slightly bluer than cyan.

The greatest region of confusion to me in rgb space is around “dirty yellow”, as in “dirty yellow” looks very much like both “dirty orange” and “dirty yellow-green”. Slightly less but still strong confusion between brown and “dirty green”.

> So, at least in some cases, “colour-blindness” is not actually an inability to differentiate colours, it’s a shift in the bands were clear differences are visible?

Yes. And the bands where clear differences are visible get narrower. In my case the red sensor moves in frequency towards the green sensor (from 580 nm towards 550 nm). So the differences between green and yellow-green are intensified, but between yellow green and red are muted. It’s more subtle than that because that description assumes a smooth spectrum – paints pigments are not smooth spectrum and the subtle jaggedness in colour due for example to the chlorophylls, xanthophylls and carotenes in green plants makes a big difference in appearance.

I wish there was a way to study the vision space of deuteranomaly that did not rely on the three colour space assumption. I’ve done the best I can in RGB space, but but that’s woefully inadequate.

One way would be to obtain pure pigments from a paint supply company. But that falls into the problem of being subtractive colour, and therefore can’t be tuned to a specific wavelength or set of wavelengths.

Using a true white light (incandescent high temperature not LED or fluorescent) and glass prism still only gives a 1-D description of colour. To get 2-D we need complete control over brightness as well. And we would need two prisms to combine pure colours to get purples and browns.

There’s also the problem of glass. I’ve noticed, have you? That glass of any description mutes the vibrancy of colour. It’s like the way that every recording of music loses the subtleties possible only with a live performance of acoustic instruments.

Using a tunable laser might be possible, but laser speckle (random flashes of light and light intensity variations in the 0.1 second time domain) dominates over colour in every laser that I’ve seen.

A true white light with a reflective diffraction grating? Not sure. Would depend on the quality of the diffraction grating and require multiple similar diffraction gratings and variable white light intensity.

I wonder if an optics lab has already done this. Determine the colour space as actually seen by deuteranomaly rather than the reduced colour space based on the rgb triangle. It’s a cross-disciple project of physics + biomedicine so may not have been done.

Quick check on web found the following chart. Spectrum of white light sources. Diagram of the spectrum a LED lamp (blue), a CFL (green) and an Incandescent (purple) superimposed the solar spectrum (yellow). Note that the energy used by each lamp is at least the area underneath its curve.

From this we can see that neither LED, incandescent or fluorescent produces anything like the flat spectrum needed for evaluating visual perception colour space. Even with sunlight it would have to be sunlight without glass (eg. without the glass on the front of a mirror).

A xenon arc lamp gets closer over the visual range, but not as good as sunlight.

mollwollfumble said:

I wish there was a way to study the vision space of deuteranomaly that did not rely on the three colour space assumption. I’ve done the best I can in RGB space, but but that’s woefully inadequate.

One way would be to obtain pure pigments from a paint supply company. But that falls into the problem of being subtractive colour, and therefore can’t be tuned to a specific wavelength or set of wavelengths.

Using a true white light (incandescent high temperature not LED or fluorescent) and glass prism still only gives a 1-D description of colour. To get 2-D we need complete control over brightness as well. And we would need two prisms to combine pure colours to get purples and browns.

There’s also the problem of glass. I’ve noticed, have you? That glass of any description mutes the vibrancy of colour. It’s like the way that every recording of music loses the subtleties possible only with a live performance of acoustic instruments.

Using a tunable laser might be possible, but laser speckle (random flashes of light and light intensity variations in the 0.1 second time domain) dominates over colour in every laser that I’ve seen.

A true white light with a reflective diffraction grating? Not sure. Would depend on the quality of the diffraction grating and require multiple similar diffraction gratings and variable white light intensity.

I wonder if an optics lab has already done this. Determine the colour space as actually seen by deuteranomaly rather than the reduced colour space based on the rgb triangle. It’s a cross-disciple project of physics + biomedicine so may not have been done.

Quick check on web found the following chart. Spectrum of white light sources. Diagram of the spectrum a LED lamp (blue), a CFL (green) and an Incandescent (purple) superimposed the solar spectrum (yellow). Note that the energy used by each lamp is at least the area underneath its curve.

From this we can see that neither LED, incandescent or fluorescent produces anything like the flat spectrum needed for evaluating visual perception colour space. Even with sunlight it would have to be sunlight without glass (eg. without the glass on the front of a mirror).

A xenon arc lamp gets closer over the visual range, but not as good as sunlight.

There is a reason we are “tuned” to sunlight you know…evolution and all that…

:)

And there is further confusion in some of the newer research on colour vision…it’s not just the photopigments in the cones. There is probably processing at the retinal level of the inputs. I’ll see if I can find you something on that.

I’m afraid it’s rather long and involved…

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5306459/

“Evolution of the circuitry for conscious color vision in primates”

Another one:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6345392/

“A tour of contemporary color vision research”