Herbivores see colours in a slightly narrower spectrum than the human eye does, but the way their brains interpret these neurological signals is completely different to that of a human. The relationship between the rod sensors (night vision) and cone sensors (day vision) in their eyes is greatly biased towards the rods and these are drastically differently arranged than in the human eye.
Human vision is amongst the sharpest of all animals thanks to densely packed “cone” receptors at the centre of our retina. Daylight vision in most animals with a rectangular slit-type iris like herbivores have, is about six times blurrier than ours. If the hunter has normal tri-chromatic vision ability blaze orange indeed is highly visible to the human eye and it no doubt is the obvious choice to increase a hunter’s visibility to other hunters.
The ungulate eye is optimised for low light - the so-called “rods” - which are the low intensity receptors that dominate the retina to the ratio of 9:1 relative to the “cone” receptors which are dedicated to bright light and colour perception.
Colour vision in the ungulate eye is produced by two populations of “cone” receptor cells in the retina. This so-called “dichromatic vision” in the white tail deer also has a further limiting feature to its ability to discriminate between dedicated wavelengths and resolution:
the few available “cone” receptors are widely spread out all over the complete surface of the retina and not clustered at a certain focal point like in the human eye.
The effect of this is that daylight signals and in particularly the green and blue wavelengths are very unfocused to the deer and that there is little or no discrimination ability between blue and green signals.
A large number of “rod” low intensity receptors in the whitetail deer eye are concentrated in a distinct area called the “Macula” which allows for enhanced low light visibility and good perception of near infra red signals.
In deer it was also found that a great many rods are connected to a single neuron, which means that sensitivity is increased, but this wide receptor distribution which all connect to only one neuron again distinctly decreases definition. Furthermore the reflective layer we all have seen when a light is shone into a deer’s eyes is also cause for more degrading of visual acuity.
To reduce the amount of daylight onto all these sensitive areas but still expose the width of the retina, a slit-type iris is employed and not the lens-central radial iris as in a human being; this design greatly decreases resolution or visual acuity.
Do you see the lioness that lay 6 yards away from the car? Only a momentary flick of the ear gave her away. They just wear even-coloured dark shade khaki.
The Zarco Scienctific Safety Camo:
As long as basic stealth principles are applied the blue pattern of this new camouflage clothing breaks up the hunter’s profile against any natural background for the herbivore eye, enhancing the hunting experience for the wearer. Unique to this material is the embedded near infra red (NIR) transmitter substance to certain sections of the pattern. This emulates the high levels of NIR radiation from the nutritious, chlorophyll laden young green leaves for which deer eyes are sensitive and breaks up the large human total NIR profile.
Appearance is a strange driver in us humans. The US rifle hunter schooled in the "RealTree" and other patterns which have become the uniform to be seen in (or not to be seen and therefore needing to wear the blaze orange jackets to be seen) - will never adopt the human very visible blue because it is too easy to be seen in it... This highly human visible but poorly deer visible pattern is ideal for bow and muzzle loader hunters who do not need to wear blaze orange. The blue camo is very visible to the human eye. Because of present low visibility to humans bowhunters also get shot by fellow bowhunters.
Visiting hunters to Africa are often surprised that his PH and tracker do not wear any camo at all. Fact is that it makes no difference to the animal really, camo or no camo. Rapid movement and discreet sounds are the big giveaway. Even scent is highly over rated - except nearer than 40 yards or so, and particularly with elephant.
My own review on the Zarco Safety Camouflage clothing is found in the PDF file here.