Looking for a colour of paint or dye that stands out as much as possible at distance against a rural background – trouble is I’m colourblind to red so, for instance, bright orange just looks like dirty yellow to me from a distance – and only jumps out at me as bright orange when I get within a few metres.

Rural colours include green – grass and shrubs, grey – shadows, brown – sticks and stalks, and yellow – too many dandelions and other yellow flowers.
Dark blue really stands out against rural colours, but only at distances of about 10 metres or less.

I need a colour that stands out as brightly brightly as possible against a rural background at distances of 50 to 60 metres during the day.

What I’m thinking of would possibly be one of the following:
a) Gloss white
b) Fluorescent white (extra brightness from converting the Sun’s UV)
c) Reflective white that shines in torchlight – like paint on road signs and lines on roads.
d) Very pale blue
e) Metallic (especially crumpled metallic that twinkles as different surfaces reflect in different directions)
f) Fluorescent orange paint
g) Fluorescene (green)
h) Chemiluminescence, eg. white phosphorus
i) Battery-powered white or blue LED

Comments, feedback please.

Why do T shirts fluoresce white? Cotton? Starch? Bleach?

Sounds like experimentation is in order.

If you are even considering a battery powered light of some sort, make it blink. That will make it stand out far more than a steady light.

mollwollfumble said:

Looking for a colour of paint or dye that stands out as much as possible at distance against a rural background – trouble is I’m colourblind to red so, for instance, bright orange just looks like dirty yellow to me from a distance – and only jumps out at me as bright orange when I get within a few metres.

Rural colours include green – grass and shrubs, grey – shadows, brown – sticks and stalks, and yellow – too many dandelions and other yellow flowers.
Dark blue really stands out against rural colours, but only at distances of about 10 metres or less.

I need a colour that stands out as brightly brightly as possible against a rural background at distances of 50 to 60 metres during the day.

What I’m thinking of would possibly be one of the following:
a) Gloss white
b) Fluorescent white (extra brightness from converting the Sun’s UV)
c) Reflective white that shines in torchlight – like paint on road signs and lines on roads.
d) Very pale blue
e) Metallic (especially crumpled metallic that twinkles as different surfaces reflect in different directions)
f) Fluorescent orange paint
g) Fluorescene (green)
h) Chemiluminescence, eg. white phosphorus
i) Battery-powered white or blue LED

Comments, feedback please.

Why do T shirts fluoresce white? Cotton? Starch? Bleach?

I think they spent a great of money before they came up with those large green signs.

If this is specific for you, you will have to experiment for yourself to a fair degree. There are a couple of types of deficiency, with different colour confusions. Do you know if you are protan (red is dull) or deutan (green is washed out).

I’ll find an online paper for you which shows the confusions.

There is an enormous amount of information in this paper:

http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2004.tb05056.x/abstract

Go to the PDF, and have a read. You are probably after a blue, people with red/green colour confusions don’t have a very colourful world.

And another one:

http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2007.00135.x/abstract

This one is a bit less technical.

white will always stand out

> Do you know if you are protan (red is dull) or deutan (green is washed out).

I used to know that, I’ve only ever visited one optometrist who tested for the difference and that was many years ago. Just did test on computer – deutan.

Know anything about either:
Where to get “optical brighteners”?
Where to get “day-glo colours”?

> Sounds like experimentation is in order.

Using paint charts from the local hardware store?

> Make it blink.

Wish I’d thought of that :-)

Have a look at those links. You are basically living in a blue and brown world (by a ‘normal’‘s perception). So as you suggested, pretty much only blue is going to stand out. And because there are different levels of deutan, you will need to experiment for you.

But as sibeen pointed out, where colour fails you, change or movement will not. You need to work with what your visual system is capable of doing.

> people with red/green colour confusions don’t have a very colourful world.

It didn’t occur to me until last year, and no optometrist has ever mentioned it, that people with red-green colourblindness could benefit greatly by having rose-coloured glasses. They may not even make rose-coloured glasses any more.

mollwollfumble said:

> people with red/green colour confusions don’t have a very colourful world.

It didn’t occur to me until last year, and no optometrist has ever mentioned it, that people with red-green colourblindness could benefit greatly by having rose-coloured glasses. They may not even make rose-coloured glasses any more.

Won’t really make a lot of difference. As evidenced by the fact that no big multinational company is selling them and making millions.

buffy said:

There is an enormous amount of information in this paper:
http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2004.tb05056.x/abstract
Go to the PDF, and have a read. You are probably after a blue, people with red/green colour confusions don’t have a very colourful world.

Have followed you advice, and also showed mrs m parts of that paper to help her understand, it’s harder for a normal-sighted person to understand colourblindness than for a colourblind person to understand normal sight. I have a tetrachromat mother, sister and daughter, and a normal sighted sister.

The second paper I linked has some pictures you could show her, which show a normal how a colour defective (don’t you love the terminology?) sees.

But she probably won’t let you cook the steak again….

buffy said:

There is an enormous amount of information in this paper:

http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2004.tb05056.x/abstract

Go to the PDF, and have a read. You are probably after a blue, people with red/green colour confusions don’t have a very colourful world.

Of course we do. It’s just different to you lot.

>>Of course we do. It’s just different to you lot.<<

Yes, and no. You have perception of far fewer hues.

mollwollfumble said:

Know anything about either:
Where to get “optical brighteners”?
Where to get “day-glo colours”?

Could I perhaps mix paint with laundry grade Optical Brightener ?

buffy said:

But she probably won’t let you cook the steak again….

Mrs m nodded as she read that one. :-) It’s something she’s noticed. It has to be VERY raw for me to see the red.

buffy said:

>>Of course we do. It’s just different to you lot.<<

Yes, and no. You have perception of far fewer hues.

But there’s all sort of mental compensations go on. For instance ever-so-faint differences in shades, textures and reflectivity are perceived. Shape recognition is more pronounced. And normal battle camouflage s quite laughable…

I may not be able to see a cricket ball on the outfield grass, but I can see where a motorcar has been repaired.

>>For instance ever-so-faint differences in shades, textures and reflectivity are perceived. <<

Is there any reason you think ‘normals’ don’t have those things?

>>Shape recognition is more pronounced.<<

Probably not.

But the thing about battle camouflage is right. It’s do do with pigments and dyes.

And interestingly, my colour perception is improving with age (as did my father’s). I’m not sure I understand why, but I suspect the mental compensations get more experienced.

buffy said:

>>For instance ever-so-faint differences in shades, textures and reflectivity are perceived. <<

Is there any reason you think ‘normals’ don’t have those things?

I’m sure they do, but like where sightless people have “better” hearing by way of compensation, I suspect poor colour vision people compensate in those areas mentioned.

>>And interestingly, my colour perception is improving with age<<

In terms of living in the world, or in terms of doing better on the tests we do?

buffy said:

>>And interestingly, my colour perception is improving with age<<

In terms of living in the world, or in terms of doing better on the tests we do?

Both.

I am interested in improvements on the tests. Do you know which ones you have done? The confetti book is the Ishihara. There is also D15 and Farnsworth 100 hue is the hardest one to do.

And particularly in discussing colours with Mrs V.

buffy said:

I am interested in improvements on the tests. Do you know which ones you have done? The confetti book is the Ishihara. There is also D15 and Farnsworth 100 hue is the hardest one to do.

Ishihara, for sure. The others? Don’t know. Doubt it.

Michael V said:

buffy said:

I am interested in improvements on the tests. Do you know which ones you have done? The confetti book is the Ishihara. There is also D15 and Farnsworth 100 hue is the hardest one to do.

Ishihara, for sure. The others? Don’t know. Doubt it.

Looked them up. I have done the F100. Once. On a computer. It is quite difficult and time-consuming.

buffy said:

But the thing about battle camouflage is right. It’s do do with pigments and dyes.

I must admit that does surprise me. The military spend shedloads on developing these things. To discount that a fair percentage of the human race are going to be colour blind, and therefore be able to pick it out quite easily seems very strange.

>>Ishihara, for sure. The others? Don’t know. Doubt it.<<

I’m going for a learning effect on the Ishihara. You’ve probably done it so many times by now that you are starting to do pattern recognition. All Ishihara books are the same. I can see the numbers on the colourblind plates, because I know what they are. (I may be a carrier, my Mum is and I’m a poor colour matcher).

I was going to be competely scathing about that session, but luckily Watson smashed a 6 off the last over to ensure that we made more than a 100 in the session.

sibeen said:

I was going to be competely scathing about that session, but luckily Watson smashed a 6 off the last over to ensure that we made more than a 100 in the session.

Err…bugger. Sorry about that.

sibeen said:

buffy said:

But the thing about battle camouflage is right. It’s do do with pigments and dyes.

I must admit that does surprise me. The military spend shedloads on developing these things. To discount that a fair percentage of the human race are going to be colour blind, and therefore be able to pick it out quite easily seems very strange.

From wikipedia “Color blindness is usually classified as a mild disability, however there are occasional circumstances where it can give an advantage. Some studies conclude that color blind people are better at penetrating certain color camouflages.”

Morgan MJ, Adam A, Mollon JD (June 1992). “Dichromats detect colour-camouflaged objects that are not detected by trichromats”. Proc. Biol. Sci. 248 (1323): 291–5. doi:10.1098/rspb.1992.0074. PMID 1354367

Also in “Unweaving the Rainbow” by Richard Dawkins
“bomber crews in the Second World War liked to include at least one colour-blind member, who could penetrate certain kinds of camouflage on the ground.”

See also BBC News article
“the (Cambridge) researchers found people with deuteranomalous colour blindness gave large difference ratings to pairs of colours which appeared indistinguishable to others. The researchers, led by Dr John Mollon, said: “The present findings recall reports from the Second World War, which suggested that ‘colour blind’ observers might be superior in penetrating camouflage.”

mollwollfumble said:

sibeen said:

buffy said:

But the thing about battle camouflage is right. It’s do do with pigments and dyes.

I must admit that does surprise me. The military spend shedloads on developing these things. To discount that a fair percentage of the human race are going to be colour blind, and therefore be able to pick it out quite easily seems very strange.

From wikipedia “Color blindness is usually classified as a mild disability, however there are occasional circumstances where it can give an advantage. Some studies conclude that color blind people are better at penetrating certain color camouflages.”

Morgan MJ, Adam A, Mollon JD (June 1992). “Dichromats detect colour-camouflaged objects that are not detected by trichromats”. Proc. Biol. Sci. 248 (1323): 291–5. doi:10.1098/rspb.1992.0074. PMID 1354367

Also in “Unweaving the Rainbow” by Richard Dawkins
“bomber crews in the Second World War liked to include at least one colour-blind member, who could penetrate certain kinds of camouflage on the ground.”

See also BBC News article
“the (Cambridge) researchers found people with deuteranomalous colour blindness gave large difference ratings to pairs of colours which appeared indistinguishable to others. The researchers, led by Dr John Mollon, said: “The present findings recall reports from the Second World War, which suggested that ‘colour blind’ observers might be superior in penetrating camouflage.”

Molly, I can understand all that, but camouflage has come a long, long way since WW2. The military industry really do spend a vast amount of money on getting it right. Not considering the colour blind population, especially given past experience, doesn’t make any sense.

There doesn’t seem to be much recent research sibeen. I found this one:

http://www.ncbi.nlm.nih.gov/pubmed/16637968

But I suspect with the way warfare is getting technological, it’s less of a problem than it used to be. Just use photos, set to find whatever it is you are looking for.

buffy said:

There doesn’t seem to be much recent research sibeen. I found this one:

http://www.ncbi.nlm.nih.gov/pubmed/16637968

But I suspect with the way warfare is getting technological, it’s less of a problem than it used to be. Just use photos, set to find whatever it is you are looking for.

You’re probably right, buffy. I suspect technology on the camouflage front has been rapidly overtaken by the tsunami of technological progress made over the last 20 years or so in the cameras/video area.

colour blindness is a throw back to the hunter gatherer gene in humans – it allows you to see better of a night and allows you to spot targets faster. I was surprised recently to see that this bloke is actually colour blind.

wookiemeister said:

colour blindness is a throw back to the hunter gatherer gene in humans – it allows you to see better of a night and allows you to spot targets faster. I was surprised recently to see that this bloke is actually colour blind.

Got any refs for the above?

Witty Rejoinder said:

wookiemeister said:

colour blindness is a throw back to the hunter gatherer gene in humans – it allows you to see better of a night and allows you to spot targets faster. I was surprised recently to see that this bloke is actually colour blind.

Got any refs for the above?

go looking around

wookiemeister said:

Witty Rejoinder said:

wookiemeister said:

colour blindness is a throw back to the hunter gatherer gene in humans – it allows you to see better of a night and allows you to spot targets faster. I was surprised recently to see that this bloke is actually colour blind.

Got any refs for the above?

go looking around

That’s your job. They’re your arguments.

Witty Rejoinder said:

wookiemeister said:

Witty Rejoinder said:

Got any refs for the above?

go looking around

That’s your job. They’re your arguments.

in my job I have to go to ask someone about stuff that not much information exists – he doesn’t know everything but he can give me enough breadcrumbs for me to start looking and finding answers.

just have a look around its a suggestion for why colour deficiency exists

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

Skunkworks said:

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

I think its the other way around

zebras have that striped pattern to confuse predators when they are running as a herd I believe?

Skunkworks said:

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

-

Huh?

wookiemeister said:

Skunkworks said:

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

I think its the other way around

zebras have that striped pattern to confuse predators when they are running as a herd I believe?

I can see that, but horses and cattle both I think see in greys, predators I think see in colours.

Skunkworks said:

wookiemeister said:

Skunkworks said:

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

I think its the other way around

zebras have that striped pattern to confuse predators when they are running as a herd I believe?

I can see that, but horses and cattle both I think see in greys, predators I think see in colours.

Somewhere in the deep recesses of my brain spills out the factoid that among mammals it is only primates that re-evolved colour vision.

Skunkworks said:

wookiemeister said:

Skunkworks said:

Would it be fair to generalise that in mammals at least (insects get into all sorts of spectrums) that prey animals are colour blind compared to predator animals? If true maybe that colour blindness helps them see through predators camouflage?

I think its the other way around

zebras have that striped pattern to confuse predators when they are running as a herd I believe?

I can see that, but horses and cattle both I think see in greys, predators I think see in colours.

Yes they do. Eyes have two kinds of receptor cells, called rods and cones because of their structure. Rods are mainly responsible for black and white vision, and cones do the colour bit. Human eyes have a predominance of cones – we see colours very well, especially in the red spectrum of light, but consequently we have a problem with night vision no matter how many carrots we eat. Lions have fewer cones so see less colour but have great night vision especially since their eyes also have a membrane that concentrates weak light back to the retina and their pupils are able to enlarge to an extent much bigger than ours. Basically, what you are asking is a very good question. We humans have a perception of the world around us that is very different from other animals, and it is mainly visual. A dog, for example, perceives the world very differently as information about the environment accumulates from a great sense of smell, a great sense of hearing, and wonderful eyesight. Humans are equipped to see wonderful differences in shades of red, but we cannot hear the crack of a small branch 20 feet away nor can we gain a whiff of the presence of drugs in a suitcase. It made selective sense in our history to have good colour vision, and it made selective sense for a dog (who can also see some colour) to hear and smell at a level we cannot even begin to appreciate!

https://www.lionaid.org/faqs_lions/do-lions-see-colour.htm

i would dispute the crack of a branch 20 feet away

i used to have to walk 3 – 4 miles through a wood in total darkness to a small cottage in national park where i was living in (where there was no sky visible). knowing the track relatively well i could feel my way through sections where the track disappeared (wasn’t particularly well defined under foot).

in these situations it was impossible for someone to jump you or approach without you knowing from some great distance – in total silence you’ll find that even the beat of wings will carry great distances of a night.

party_pants said:

Somewhere in the deep recesses of my brain spills out the factoid that among mammals it is only primates that re-evolved colour vision.

To see which berries are ripe? Fairy nuff, I have been unsure and framed my questions and suppositions with caveats.

IWMV.

I easily see very slight variations in colour (repaired cars are a good example) and military cammo is, as MV says, laughable – It’s so visually obvious to me I have trouble believing ‘normal’ sighted people can’t see it.

To address the question, I find flouro yellow, lime green or silver, especially when flickering or blinking, easiest to see at a distance.

>i used to have to walk 3 – 4 miles through a wood in total darkness to a small cottage in national park where i was living in (where there was no sky visible). knowing the track relatively well i could feel my way through sections where the track disappeared (wasn’t particularly well defined under foot).

I call shenanigans. In total darkness it is virtually impossible to find your way through a wood, track or no track. I have lost my way walking between my shed and the house when there is total darkness, on a track I walk a dozen times a day.

wookiemeister said:

i would dispute the crack of a branch 20 feet away

Yeah, as some of you will hopefully recall, my favourite rant about how the brain locates sound includes the factoid that sharp cracking sounds that spray across a broad spectrum of frequencies, like a twig breaking, are the easiest to locate in space. I would also be extremely surprised of the Human brain could not hear and locate a tiny branch, even a toothpick, at 20 feet.

morrie said:

>i used to have to walk 3 – 4 miles through a wood in total darkness to a small cottage in national park where i was living in (where there was no sky visible). knowing the track relatively well i could feel my way through sections where the track disappeared (wasn’t particularly well defined under foot).

I call shenanigans. In total darkness it is virtually impossible to find your way through a wood, track or no track. I have lost my way walking between my shed and the house when there is total darkness, on a track I walk a dozen times a day.

yes really – no light at all – no reference

when you walked the path long enough you could predict what was coming next, a tree root that fell in a particular way

if i were walking somewhere strange i would get lost so never left the path

Rule 303 said:

wookiemeister said:

i would dispute the crack of a branch 20 feet away

Yeah, as some of you will hopefully recall, my favourite rant about how the brain locates sound includes the factoid that sharp cracking sounds that spray across a broad spectrum of frequencies, like a twig breaking, are the easiest to locate in space. I would also be extremely surprised of the Human brain could not hear and locate a tiny branch, even a toothpick, at 20 feet.

you could hear people’s voices at great distance of a night

the other great advantage of the darkness is that even nutters would give you a wide berth – WTF are you doing walking around silently in the woods? you’d hear anyone approaching, in total darkness remaining still gives you an immediate advantage – assuming they weren’t using night vision.

After smelling cigarette smoke I thought someone was very close to my house, I couldn’t see anything when I looked out the door but the smell persisted. I snuck out the back and sat for a good 20 minutes doing a listening post and waiting till my eyes adjusted. Then I did a sneak using the looking off technique where you try not to look at your target but see it peripherally.

In the military you use red lights to read maps etc and when going into lighted tents try and keep an eye closed to preserve one eye for night vision. PS don’t use red markers on map overlays used for night work.

wookiemeister said:

morrie said:

>i used to have to walk 3 – 4 miles through a wood in total darkness to a small cottage in national park where i was living in (where there was no sky visible). knowing the track relatively well i could feel my way through sections where the track disappeared (wasn’t particularly well defined under foot).

I call shenanigans. In total darkness it is virtually impossible to find your way through a wood, track or no track. I have lost my way walking between my shed and the house when there is total darkness, on a track I walk a dozen times a day.

yes really – no light at all – no reference

when you walked the path long enough you could predict what was coming next, a tree root that fell in a particular way

if i were walking somewhere strange i would get lost so never left the path

—-

The blind leading the blind.:)

Skunkworks said:

After smelling cigarette smoke I thought someone was very close to my house, I couldn’t see anything when I looked out the door but the smell persisted. I snuck out the back and sat for a good 20 minutes doing a listening post and waiting till my eyes adjusted. Then I did a sneak using the looking off technique where you try not to look at your target but see it peripherally.

In the military you use red lights to read maps etc and when going into lighted tents try and keep an eye closed to preserve one eye for night vision. PS don’t use red markers on map overlays used for night work.

in training they tell you about the third man with the third cigarette

you first see the first drag – the glow of the fag

you then look through thr scope and see the second drag by the second man

you see the third drag and fire at the glow – bang – dead

in a forest environment the glow of a fag can be seen easily

from what i saw the dutch have no training in keeping torches covered

wookiemeister said:

Rule 303 said:

wookiemeister said:

i would dispute the crack of a branch 20 feet away

Yeah, as some of you will hopefully recall, my favourite rant about how the brain locates sound includes the factoid that sharp cracking sounds that spray across a broad spectrum of frequencies, like a twig breaking, are the easiest to locate in space. I would also be extremely surprised of the Human brain could not hear and locate a tiny branch, even a toothpick, at 20 feet.

you could hear people’s voices at great distance of a night

the other great advantage of the darkness is that even nutters would give you a wide berth – WTF are you doing walking around silently in the woods? you’d hear anyone approaching, in total darkness remaining still gives you an immediate advantage – assuming they weren’t using night vision.

One evening I went to a local cemetery and climbed a tree to investigate a luminous mushroom that was growing up there. It wasn’t totally dark, but the light was fading and it was starting to rain. When I jumped to the ground I landed right in front of a bloke walking his dog. I don’t know who got the biggest fright. :)

the 5.56 SUSAT was very useful for shooting of a night

the needle head would be exposed to a tritium source and would glow (phosphor)

you could very easily zero down onto any lit target of a night

the steyr has that silly cross hairs thing – i found the needle head very useful and better for target practice oh yes it has 4times magnification rather than the abysmal 1.5 mag of the steyr – which helped immensely to see what the hell you were shooting at

make that 5.56mm rifle with SUSAT

Skunkworks said:

After smelling cigarette smoke I thought someone was very close to my house, I couldn’t see anything when I looked out the door but the smell persisted. I snuck out the back and sat for a good 20 minutes doing a listening post and waiting till my eyes adjusted. Then I did a sneak using the looking off technique where you try not to look at your target but see it peripherally.

In the military you use red lights to read maps etc and when going into lighted tents try and keep an eye closed to preserve one eye for night vision. PS don’t use red markers on map overlays used for night work.

I have found people wandering on my place from the smell of cigarette smoke, from 100 metres away on the track they had walked down.

morrie said:

Skunkworks said:

After smelling cigarette smoke I thought someone was very close to my house, I couldn’t see anything when I looked out the door but the smell persisted. I snuck out the back and sat for a good 20 minutes doing a listening post and waiting till my eyes adjusted. Then I did a sneak using the looking off technique where you try not to look at your target but see it peripherally.

In the military you use red lights to read maps etc and when going into lighted tents try and keep an eye closed to preserve one eye for night vision. PS don’t use red markers on map overlays used for night work.

I have found people wandering on my place from the smell of cigarette smoke, from 100 metres away on the track they had walked down.

now you wait for them in the branches and jump down with your arms holding a cape wide open bearing your fangs with with a small UV light for max impact – only the foolhardy and drunks dare walk the track now

>>holding a cape wide open bearing your fangs<<

Rubbish! Capes don’t bear fangs. Fangs belong in mouths.

OK, about colour vision in animals….I haven’t read this in its entirety, but it looks like a rather good overview:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781854/

Lots of technical stuff, but readable.

I am red/green colour blind as indicated by the Ishihara colour blindness test, but I can’t understand what this means, as I can tell the difference between signal red, signal green, and white light. Does this mean that I see blood the way non-colour blind people see grass and vice-versa?

Have a look at the links I put up early in this thread bob.

Ta buffy.

Skunkworks said:

I can see that, but horses and cattle both I think see in greys, predators I think see in colours.

Horses, dogs and cats are dichromats – their colour vision is somewhat like red-green colour blindness in humans.

Primates are trichromats and birds are tetrachromats.

Ian said:

Skunkworks said:

I can see that, but horses and cattle both I think see in greys, predators I think see in colours.

Horses, dogs and cats are dichromats – their colour vision is somewhat like red-green colour blindness in humans.

Primates are trichromats and birds are tetrachromats.

>>Fish

The goldfish (Carassius auratus auratus) and zebrafish (Danio rerio) are examples of tetrachromats, containing cone cells sensitive for red, green, blue and ultraviolet light.

Birds

Some species of birds such as the Zebra Finch and the Columbidae use the ultraviolet wavelength (300–400 nm) specific to tetrachromatic color vision as a tool during mate selection and foraging. When selecting for mates, ultraviolet plumage and skin coloration show a high level of selection. A typical bird eye will respond to wavelengths from about 300 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430–1000 THz.

Insects

Foraging insects have the ability to see wavelengths that flowers reflect (ranging from 300 nm to 700 nm). Pollination being a mutualistic relationship, foraging insects and plants have coevolved, both increasing wavelength range: in perception (pollinators), in reflection and variation (flower colors). Directional selection has led plants to display increasingly diverse amounts of color variations extending into the ultraviolet color scale, thus attracting higher levels of pollinators. Some pollinators may use tetrachromatic color vision to increase and maintain a higher foraging success rate over their trichromatic competitors.<<

http://en.wikipedia.org/wiki/Tetrachromacy

Bubblecar said:

Sounds like experimentation is in order.

Preliminary experiments in a nearby park.
Chose to try white, pale blue, deep blue, fluoroscein-like green, yellow, orange and alfoil metal.

First experiment – in sunshine on green grass – from best to worst:
white, deep blue, yellow & green, orange, pale blue, metal.
White was visible at 45 metres.

Second experiment – in shadow on grey bark – from best to worst:
green, white, deep blue, yellow & orange & pale blue, metal.
Green was visible at 20 metres or more.

So in summary so far, white seems best followed by either deep blue or fluoroscein-like green. Results not definitive yet, because colour cards came in several different sizes, and I couldn’t match orientations. I also have a whole swathe of different “white“s to try. Including white glitter and white paper. Unfortunately, I wasn’t able to find the advertised whitest white paint, with 10% brighter white.