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UV in clothing

Old 06-18-2008, 12:43 PM
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Default UV in clothing

I'm sure we've all heard about the uv in our hunting clothing that allows nocturnal animals like deer to view us as a big blob of blue.
Is there any proof to this or is it justa catch to make more hunters hunters spend more money?

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Old 06-18-2008, 01:01 PM
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North American white-tailed deer have been tested! The research was conducted from August 24 to 29, 1992, at the University of Georgia D. B. Warnell School of Forest Resources, in Athens, Georgia. Present were Dr. R. Larry Marchinton and Dr. Karl V. Miller of the University of Georgia with a staff of graduate students headed by Brian Murphy as research coordinator. The electroretinograph was administered by Dr. Jerry Jacobs and his assistant Jess Deegan of the University of California, assisting was Dr. Jay Neitz of the Medical College of Wisconsin. The Electroretinograph equipment, provided by Dr. Jacob’s lab, is the culmination of 12 years of refinements. Computer controlled light presentation and signal processing now enable scientists to accurately define the range of vision in animals.

Following is the abstract of what was presented to the Southeast Deer Study Group in February 1993.
PHOTOPIGMENTS OF WHITE-TAILED DEER
Brian P. Murphy, Dr. Karl Miller, and Dr. Larry Marchinton, University of Georgia; Jess Deegan II, University of California; Dr. Jay Neitz, Medical College of Wisconsin; Dr. Gerald H. Jacobs, University of California.
All aspects of vision depend ultimately on the absorption of light by photopigments. The retinas of white-tailed deer (Odocoileus virginianus), like those of other ungulates, contain a mixture of rod and cone photoreceptors. We have used a noninvasive electrophysiological technique to measure the spectral absorption properties of the photopigments contained in these receptors. In this procedure, electroretinogram (ERG) flicker photometry, light-evoked potentials were sensed by a contact-lens electrode positioned on the eye of an anesthetized deer. The eye was stimulated with a rapidly-pulsed, monochromatic light; variations in pulse rate, stimulus wavelength and adaptation state of the eye allowed preferential access to signals from different classes of photoreceptor. Recordings were obtained from nine white-tailed deer. Three classes of photopigment were detected. One of these is the photopigment contained in rods; it has a peak sensitivity of about 496 nm., a value greatly similar to that found for rod photopigments of other mammals. These measurements also reveal the presence of two classes of cone. One contains a photopigment maximally sensitive in the middle wavelengths (peak value of 537 nm); The other cone class has a sensitivity peak in the short wavelengths, at about 455 nm. In light of what is known about the relationships between photopigments and vision in other species, these results suggest two likely characteristics of cone-based (i.e., daylight) vision in deer: (1) deer should be relatively less sensitive to longwavelength lights than many other mammals (e.g., humans), and (2) white-tailed deer would be expected to have dichromatic color vision.
In addition to this study which used the ERG to detail the spectral sensitivity of the deer, there have been recent spectro radiometric studies of ambient light and blaze orange with and without U-V-KILLER treatment. Following is an
interpretation of the results of both of these studies by Dr. Jay Neitz, Medical College of Wisconsin.
[align=center]PHOTORECEPTORS AND DAYLIGHT VISION OF THE DEER [/align]
Vision is initiated when light is absorbed by photoreceptors of the retina, the light absorbing tissue that covers the back of the eye. The limits of vision depend on several factors, which include: In addition to this study which used the ERG to detail the spectral sensitivity of the deer, there have been recent spectro radiometric studies of ambient light and blaze orange with and without U-V-KILLER treatment. Following is an interpretation of the results of both of these studies by Dr. Jay Neitz, Medical College of Wisconsin.
PHOTORECEPTORS AND DAYLIGHT VISION OF THE DEER
Vision is initiated when light is absorbed by photoreceptors of the retina, the light absorbing tissue that covers the back of the eye. The limits of vision depend on several factors, which include:
(1) The optical properties of the eye, i.e., the size of the eye, the size of the pupil, the refractive power of the eye's optical elements.
(2) The properties of light absorbing filters through which light must pass before reaching the photoreceptors. In humans these include filters in the lens and in the central region of the retina that absorb strongly in the short wavelengths, blue, violet and ultraviolet.
(3) The light absorbing properties of the photoreceptors themselves, the number of different classes of photoreceptors and their distribution in the retina.
(4) The reflectivity of tissues that lie behind the photoreceptors. For example, many animals that are active in dim light have a reflective layer at the back of the eye that enhances sensitivity.
Some of these properties have been recently investigated for the eyes of whitetailed deer. A non-invasive procedure (harmless to the deer) was used on anesthetized deer to measure the sensitivity of the deer's eyes to wavelengths of light across the spectrum.
Deer like all other mammals have two types of photoreceptor, rods and cones. The rods are responsible for vision in dim light and the cones are responsible for vision in daylight. The light absorbing properties of the rods in deer were found to be similar to those found in other mammals, including humans. Two classes of cone photoreceptor were detected in the deer. One most sensitive to shortwavelength light (blue-violet); the other most sensitive to middle-wavelength light (green-yellow).
The lens of the human eye contains a yellow pigment that absorbs ultraviolet light almost completely; it absorbs strongly in the violet and into the blue spectral regions. In contrast, the transmission of short wavelength light is very high for the lens of many mammals that are active at dusk, dawn and at night. The recent experiments indicate that this is true for the deer. The relative sensitivity of deer eyes to short wavelengths (blue and violet) is high compared to that of humans, as expected because deer lack yellow pigment in their lens.
In humans, the very central region of the retina (the fovea) is specialized for high acuity vision. Among mammals, this specialization is found only in humans and other primates. Also unique to primates is an additional yellow pigment, the macular pigment that covers and thus screens the central region of the retina. Humans use the central region of the retina whenever we look directly at an object; it is this region that we depend on most heavily for vision. Thus, when comparing the daylight vision of deer to that of humans it makes sense to consider human foveal vision.
The recent experiments suggest important differences between the daylight vision of deer compared to that of humans:
(1) Humans have three classes of cone photoreceptors which are the basis of trichromatic (literally three-color) vision. In humans this three-receptor system confers excellent color vision. Humans can distinguish small differences in wavelength across the spectrum. In contrast, only two classes of cone photoreceptors were detected in deer. Deer can have no better than dichromatic (two-color) vision. Thus, the color vision capacities of deer are, at best, limited compared to humans. The two classes of cones in deer allow for the ability to see color differences between short and long-wave lights, e.g., blue and yellow, however, they lack the photoreceptor basis for seeing differences in the color of objects that reflect middle-to-long wavelength light, e.g., yellow-green, green, yellow, orange, and red.
(2) Since humans have yellow pigments that screen out short-wavelength light, the relative sensitivity of deer to short wavelength light is much higher that the sensitivity of humans. This same difference would apply to low light conditions under which only rod photoreceptors operate.
(3) The three classes of cone photoreceptors in humans are each sensitive to a different region of the visible spectrum. Together these confer sensitivity to a wide band of wavelengths. The three classes of human cone photoreceptors can be termed red, green and blue cones. One of the two cone photoreceptors detected in deer is similar to the human blue cones; the other is similar to human green cones. Thus, compared to humans, deer effectively lack red cone photoreceptors. This suggests that deer should be relatively less sensitive to long-wavelength light (orange and especially red) than humans. Human sensitivity is highest in the green-yellow region of the spectrum and, for equal intensities, these wavelengths are perceived as brightest. Humans are relatively insensitive throughout the short-wavelengths (blue and violet). Sensitivity also drops off rapidly in the very long wavelengths, e.g., we are relatively insensitive to deep reds. Humans can distinguish four basic colors; blue, green, yellow and red. We also distinguish dozens of intermediate colors, e.g., violet, blue-green, yellow-green, orange etc. Humans can make subtle color discriminations across the visible spectrum.
The region of highest sensitivity for the deer is at a shorter wavelength than that of humans. The relative sensitivity of deer to short-wavelength light is dramatically higher than human sensitivity to those wavelengths. For equal intensities, deer are expected to see short- and middle-wavelengths as brightest. Because of the absence of red cones, the drop off in sensitivity at the long-wavelength end of the spectrum occurs at shorter wavelengths for deer. They are less sensitive in the spectral region that appears orange to humans and are virtually insensitive to deep reds. With only two classes of cone photoreceptors, deer can distinguish no more than two basic colors, one for the short wavelength end of the spectrum and another for the middle-to-long wavelength end of the spectrum. Animals with dichromatic color vision do not see an intermediate color in the spectral region between the two colors. That is, they do not see a color that appears bluishyellow. Instead they see the intermediate spectral region as colorless (gray).
The issue of how deer see blaze orange is of considerable interest to hunters and those interested in hunter safety. Recent results lend insight into how deer may perceive blaze orange. Blaze orange is highly visible to humans because, for us, it is both intensely bright and intensely colored. The worst news for hunters would be if blaze orange was seen by deer as intensely colored and intensely bright as it is for humans. At the other extreme, perhaps the best news would be if blaze orange was not seen at all by the deer. Given what is known about deer vision neither of those extremes is likely to be true. The recommended specification of blaze orange requires a dominant wavelength between 595 and 605 nanometers. Deer are expected to see this band of wavelength. However, the deer’s relative sensitivity to 605 nanometers is less than half the relative human sensitivity. Although 605 nanometers is expected to be seen by deer as colored, that color would not be different from long-wavelength lights (the ones we see as red, yellow and yellowish-green).
Wavelengths that deer are likely to be able to distinguish from 605 nanometers are the ones we see as violet, blue, blue-green, and pure green. A garment that emitted only an intense band of light at 605 nanometers would be less colored and less bright to deer than it is to humans. However, it is important to understand that such a garment would be far different from an ideal camouflage. It would still stand out as colored and/or bright against dark backgrounds, against bluish-greens, pure greens, browns, tans, and grays.
Finally, the issue of how deer see short-wavelength light has received considerable attention. Recent results also lend insight into this issue. �The difference between daylight human foveal vision and daylight deer vision is expected to be even more dramatic for short-wavelength light than it is for longwavelength light. Humans are very insensitive to wavelengths below 450 nanometers. For example, relative to other wavelengths, deer are about eight times more sensitive than humans to lights of wavelengths near 430-440 nm (such as those emitted by UV brighteners). Garments can reflect (or emit) considerable light in this spectral band. Because of the deer�s high relative sensitivity to short wavelength light, the presence of blue, violet and UV components would make a garment stand out as both bright and colored against natural backgrounds. Those same components could be barely noticeable to humans.� Dr. Jay Neitz
This information about color vision is also summarized by the graphs on the outside front cover. More examples of Dichromatic vision are found on Dr. Neitz’s web site www.edu/cellbio/colorvision/test.htm.

[align=center]Significance of these findings to the hunter. [/align]Much has been written lately about how UV brighteners effect a deer's perception of camouflage, blaze orange, and other garments. In order to apply what has been learned about the visual systems of the deer we must define how UV brighteners effect the garment being seen. This is further complicated by the spectral composition of the ambient light in which the garment is viewed.
We can simplify the effects of variations in ambient light by simply assuming that, for the sake of a discussion about the effect of UV brighteners, we are talking about a time and place where Ultraviolet light is a high percentage of available light. In direct sun at high noon the longer wavelengths overwhelm our visual system completely and we see no effect from UV brighteners. As we move to dusk, dawn, deep overcast, or shade the absolute amount of UV and short blue light decreases, but the percentage share of total light contributed by UV increases greatly. We therefore confine discussion of UV brighteners to times and places where their effect is significant.

The garment's color and other optical characteristics are also significant. Ignoring most variations again allows us to focus on the effects of UV brighteners. It should be noted, humans are very insensitive to UV and short blue wavelengths so the effects can only be observed (if at all) on white or light colored garments, unless a UV light source is used to enhance the effect. The deer, however, see these effects on almost any color. The background is also significant. Cones and Rods are classed by their wavelength of maximum sensitivity. Deer have cones sensitive to short (blue & UV) wavelengths and middle (green & yellow) wavelengths and no cones for long (red) wavelengths. Human cones are mostly long (red) wavelengths. We also have a good percentage of medium (green & yellow) wavelength cones, but fewer than 10% of our cones are the short (blue & UV) variety. The sensitivity of our few blue cones is further suppressed by our UV filter. At low light our disadvantage in the short wavelengths is even greater because we have so few rods. Deer are simply able to see short wavelengths better than humans in all conditions.
The research also verified that “Deer are much less sensitive to longer wavelengths than humans”. This means that if a blaze orange vest had no UV brightener dyes and was purely 605-nm blaze orange, the deer would not see it as we do. (See back cover) They lack our red cone completely. They’re green cone peaks at 537-nm, almost 70-nm away. Dramatic as this difference in sensitivity is, it is only part of the story. From studies of colorblind humans who have the same two cones as deer, we know that their color vision is limited to shades of blue and yellow.
“White-tailed deer would be expected to have dichromatic color vision.” Human dichromats called protanopes also lack the red cone function. A human with one dichromatic eye (blue/green cones) and one trichromatic eye (blue/green/red cones) can tell us the difference in color perception. They see blue as blue and the rest of the spectrum from green to red as the color yellow, with their dichromatic eye. Therefore, if blaze orange or most green/brown camouflage is without UV brightener effect, Deer will see it as yellow. It will all blend in well in a world of green leaves, yellow grass, and brown trees, because they too are all yellow.”
Now consider what effect UV brighteners would have on these garments that appear yellow in a yellow world. Blue flags? Yes, especially on blue, white, light shades of gray, and other colors that have some blue content. Other colors will simply appear brighter and whiter much as intended for humans. In low light the problem is even greater.
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Old 06-18-2008, 01:05 PM
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IMO - it's a farse....
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Old 06-18-2008, 02:10 PM
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ORIGINAL: WKP Todd

IMO - it's a farse....
I like short posts!!

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Old 06-18-2008, 02:15 PM
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ORIGINAL: MeanV2

ORIGINAL: WKP Todd

IMO - it's a farse....
I like short posts!!

Dan

I like to copy and paste.[8D]
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Old 06-18-2008, 02:37 PM
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Default RE: UV in clothing

I read the whole dang thing.[:@]
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Old 06-18-2008, 02:53 PM
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ORIGINAL: peakrut

I read the whole dang thing.[:@]
I think there is some pretty good info in there. Didn't you?
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Old 06-18-2008, 05:24 PM
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Default RE: UV in clothing

I believe it, my cuddeback no flash I swear they can see that IR.....flash etc...

makes sense, some animals can't see color...others can, why can't deer see a different range/spectrum than humans? dogs can hear a different range.....etc...very possible, and very likely IMO.


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Old 06-18-2008, 06:54 PM
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Default RE: UV in clothing

Oh boy, it was a 5 day exhaustive study. LOL Probably done as part of a research grant by the guy trying to market UV wash. Don't worry about it. Use unscented clothes was and you're good to go.
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Old 06-18-2008, 07:01 PM
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Oh boy, it was a 5 day exhaustive study. LOL Probably done as part of a research grant by the guy trying to market UV wash. Don't worry about it. Use unscented clothes was and you're good to go.
Sounds like some Government funded studies I've known. No! Wait a minute! They take years and cost Billions, but you get about the same results[8D]

On Gas, I wonder if there really is price gouging? We need a study for that.

I think as long as you use unscented detergent with zero UV brighteners you'll be good to go.

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