The problem of star colours is an interesting one. Much has been written about star colour and very likely much will be written about it in the future. During the 1800’s observations of star colours were adopted with great interest. Without the advantage of astronomical spectroscopy little was known about the temperatures of the stars, and with careful observation some information could be obtained but much of it today could be discarded as unimportant. Today, there still are many poor and inaccurate views about star colours - some which have persisted for more than one-hundred years. One of the worst aspects that have been adapted are the colour descriptors used, and it is a little hard to understand how border-line colours like gold, crimson, lilac, grey or ashy can be described.
Some will often innocently exaggerate the colours they see and want to present more exotic colours to make them either original or accepted in the amateur astronomical community. Few can be seen as faux pas that still appear in articles in the popular astronomical press. In my own opinion several of them can only be described as “new-age charlatans” by claiming either personal superior colour vision based on the whimsical notion of the observer being the better sex or having better colour perception. I have even seen star colours seriously presented as apricot, peach, amber, silver-white, lemon-brown, beige, khaki, or even turquoise! These were even mixed with so-called reflectance terms like gloss, translucency or shadowy. Such descriptions are just pure and utter nonsense because they are visual colours which verbally have arbitrary meanings - meanings that convey nothing at all to another person and are only useful to the individual that gave them.
Worst with these people is that colours they are describing are physiologically impossible to see at night as they are highly rich saturated colours (Something we will discuss in this very page.) or are odd mixtures with the tones of black and/or white - something that is not seen in the continuous spectra of the stars. These types of amateur observers should be discredited immediately because they give a poor representation of the many good, dedicated and sensible amateur astronomers.
Perhaps here I’m being a bit too critical, but I only wish to highlight that using more specific simpler colours are far more useful than to try to match precisely what shade of colouration one particular star or double appears to be.
Much of the mechanism about colour vision unfortunately does not work as well at low illuminations. The main flaws lie with the cones in the retina of the eye which gain nearly all of the light needed for interpreting colour. It seems the human eye for all its biological wonder was just never designed for good night vision. Worst, there is no doubt that an observer’s age is likely the main cause for the eventual loss of the ability to interpret the spectral range. More unfortunate is that the younger the individual, the less able they can describe the colours they see just through lack of experience! However, the real experts in recent times about eye colour perception have been by several French observers, with several interesting papers in the last twenty to thirty years or so. For example, I have a translated version by Paul Biaze written in the 1980’s which is quite analytical and very innovative. An excellent summary of this subject about star colour appears in David Malin’s Colours of the Galaxies (1996).
The study of colour perception about stars is incomplete, and this general article is about the cause of colours that we see in telescopes and why they are so hard to observe. It was also written to counteract the seeming avalanche of some new double star observers who have been claiming to have superior vision or colour perception. Please, if you are one of those observers that believe what I am saying is wrong, then I suggest you reading the next four paragraphs carefully before reading the rest of the text.
At the telescope any observed colour is more often than not fairly poor. This certainly is a physiological problem as the human eye at night cause the loss of colour vision. The mechanism of vision lies with the so-called "rods" and "cones" within the human retina. Each eye contains an average 137 million light-sensitive cells at a mean density of 650 per square millimetre. These are ratioed to some 617 black and white rods with 33 beiing colour cones. Some 7 million of the total are cone cells, whose density are divided into thirds equally being either red, blue or green-sensitive. There is no known difference in the number of rods or cones between males and females.
Rods measure the intensity of light in the eye (greyness) and respond very little to colour. As light intensities vary so much, ranging from full sunlight to the near pitch-blackness of night, the need for such a mechanism is obvious. It also affords the detection of contrast. An analogy of this is similar to the controls of a black and white television. The "rods" will work whatever the intensity of light.
Cones are the colour receptors, and as their names suggest, are in the shape of a cone whose diameters reduce almost to a point. For this reason they are poor light receptors, but with enough illumination, the wavelengths coming into to eye can be separated in to their component colours. The signals are then sent along the optic nerve of the brain and interpreted as colour. The details on how our eyes do this in unnecessary, and chemically complex, for an understanding.
For nighttime observers much of the colour is lost to our eyes during the night. The simple reason is that cones have a threshold for colour sensitivity and below particular light energies (flux) almost all completely cease to work. Consequently, when we look at our surrounds during the night, we see only a slight range of "greyness". Looking through any telescope, we are immediately exposed to the illumination by the field stars and the astronomical object(s) in question. Most stars just appear white in colour, but in some circumstances like the very blue or very red stars, we do see some colour. Also the fainter the star or object the less colour we see, hence colour is also magnitude dependant. These colours we see are different from what we mostly see during our everyday living because at night we perceive very few hues. This is due to the colour component known as saturation that can be described as the degree of whiteness in any perceived colour. Saturation is fairly weak for stars. In astronomical objects these produce only pale colours and never intense ones. The only true exception is the deep-red carbon stars which have little blue or yellow light contributing to their spectra, but such stars are unusual and rare. Seeing colours at night with is unusual because we can see no more than about 10% Saturation. Experience finds that the more intense colours simply cannot be observed. The amount of saturation varies slightly between different individuals, and is visually dependant on the background colour it is seen against.
The colour able here shows the colours red, orange, yellow, light blue and deep blue. Colour saturations above 10% are never seen in stars or nebulae. 0% colour saturation is the pure white. 100% saturation colours are often termed as pure colours.
The following figure shows the effect on 20% saturated colours seen against either a black or a white background. Each colour against each alterative background are identical, but visually our eyes see that those against the lighter background make the inside circle’s colour seem to be slightly darker. This is caused by the colour contrast as seen by the eye and is comparable to looking at stars, for example, during darkness as compared to either twilight or daylight (as the background). Similarly, pairs with quite different temperatures finds a similar visual effect which enhances the visual colour differences. Amateur observers should also note that as the magnification is increased by using different eyepieces that background field is seen as slightly darker and this has an effect of changing the observed colour slightly.
Any real need for estimating colour in telescopes is likely not very important for most visual observers, but for those engaged in writing astronomical descriptions or promoting astronomy, such colour reports are both interesting and important to advise, interest and can guide other deep-sky observers and amateurs.
Based on the experiments by the visual physiologist Denis Baylor in 1978, it is possible to conclusively dismissed the ecumenical misconceived notions of colour discrimination through the telescope. (See References) These original detailed experiments were conducted at the Department of Neurobiology at Stanford University whose aim was specifically to measured the eye’s photon response in darkness. Attaching a photometer to individual rod and cone cells in the human retinas, he then measured photoelectrically the response of the photons of various monochromatic colours. His main conclusion found that at low illumination, all the cone cells switch off, and nearly ceasing their electrical function. It is for this reason that the loss of colour vision at night was explained and the first time quantatively determined. Baylor says about his results;
‘This state of affairs makes it impossible for one cell, either a rod or cone, to signal separately wavelength and intensity. Consider a single rod upon which falls 100 photons of 550nm wavelength. These photons will be absorbed with the probability of say 10%, so that a total of ten absorptions will occur. Ten absorptions would also occur if 1000 photons were incident at 600nm. A particular wavelength therefore has the mean probability of absorption of only 10%. Since the cell reports only the number of photons absorbed, the signals generated by the two coloured lights are identical, even though their wavelengths are different. Hence no colour (wavelength) information is available. This explains why in starlight, where only the rods contribute to vision, we have no colour sensation.’
From this we can conclude as the rods receive the light, then it is the brain which tries to interpret the colours it is seeing. Furthermore, as the star colours are never saturated, so what we generally see is only slight variations in hues.
One of the first important colour scheme in stars was first made by the as astronomer Chandler (1901) (Chandler Scale - CI) producing seven basic colours. The southern double star observer R.T.A. Innes was one of Chandler’s greatest critics stating that he placed little credence in knowing star colours as they could be obtained photographically using two films or by instrumentally by photometry. I could not find any information relating to whether Hagen accessed Chandler’s work, but personally I see much usefulness in Chandler’s Scheme because I can easily distinguish these colours in the telescope and I assume the same for the majority of people !
J.G. Hagen, who incidentally specialised in
eclipsing binaries, produced a new logical colour
scale in 1924 - essentially the later version of
the previous and poor adopted Chandler Index. Now
known as the Hagen Colour Index (HCI)
labelled star colours ranging between the values of
-3 for Blue and +10 for
Red with 0.0 corresponding to the B-V value
of 0.0. This particular colour scheme has remained
the nomenclature now often adopted by amateurs who
do variable star observations or for the
measurements of pairs.
Colours in this scheme were Blue, Bluish, White, Yellowish, Yellow, Orange and Red. Hagen simply just adds additional colour values for these seven basic colour elements.
|-2||Pale Blue (Bluish)|
|-1||Blue / White|
|2||Pale Yellow (Yellowish)|
|5||Yellow / Orange|
|7||Reddish / Orange|
|8||Orangey / Red|
|9||Red / Orange|
Most visual observers tended to use the Hagen Colour Index (HCI) which relates closely to stellar surface temperatures and the B-V Colour Index. No one truly adapted this as an “analytical” method, but as an extra means of determining the “correct” position angle of both the stars, especially when the magnitudes are nearly equal.
Note: The original observer’s designation overrides the estimation of the brightest against the faintest star. This means the designation of "A" and "B" components are preset by the discoverer. The HCI has some analytical basis, however the linearity with visual divisions in quite poor. Ie. The values of say white to yellowish are different from say from blue to bluish or red to reddish.
Figure 3 shows the Hagen Colour Index Scale with both 10% Saturation, the likely maximum visible colour, and 20% Saturation. I have contrasted the colours against both black or white backgrounds so the visibility of the colours and the contrast effects can be seen. The Figure above clearly shows these differences. All observed colours will be also slightly different when they are pinpoints, and the colour presented here are closer to the defocussed star images that can be seen in the telescope. Observers should note that I have calculated the colours to be approximately 10% and then I have had to make several small adjustments so that the colours look a bit more consistent. However this changes are quite likely inconsequential for many visual observers. Most stars will be fainter than the colours presented here and nearly all of the fainter stars will have almost insignificant saturations.
Anyone using the colours for observational comparison should ONLY use the 10% SATURATION SCALE.
It was M. Minnaert who first discussed star colour in modern terms. If we assume that star colours are based on the black body properties of objects, as seen in a ultra-hot furnace (Ie. The famous simple experiment it to heat a small piece of metal (like Tungsten) where, as the temperature rises, the metal is coloured from red-hot, yellow-hot, white-hot then blue-hot.) we will find this will follow the observed spectral sequence and B-V colour index - but without green.
Minnaert then adopted the series of eight separate colour groups he could distinguish by eye, and then by doing a "blind" experiment, compared his colour estimates with the B-V colour index. This proved to have a high correlation. From this, he first achieved the feat of distinguish the spectral class letter of the object. Minnaert gained much kudos for this in his day !
Minnaert also investigated the colour of the white and yellow stars, finding that they could distinguish the yellow ones into white-yellow, light yellow, pure yellow and deep yellow. (The reason for this, I think, is that the eye is more sensitive to seeing this part of the spectrum, especially when compared with the red, and the far blue.) Interestingly, his experiments validates the problems of colour saturation. His book concludes that only eight major or "primary" star colours corresponding to the mid-spectral classes of O, B, A, F, G, K, M, S.
Figure 4 shows the colours of the Spectral Classification at 10% Saturation. The colours can be estimated in the telescope with care, but observers should note that these are the maximum colours and most of the stars have much lower saturated colours. I have contrasted the colours against both black or white backgrounds so the visibility of the colours. The colours here are suitable for using in drawings of star charts where the spectral class is required.
Anyone using the colours for observational comparison should ONLY use this 10% SATURATION SCALE.
According to David Malin (AAO), it was the astronomer Leslie Morrison from the Royal Greenwich Observatory who attempted visual observation of stars through the transit telescope, and doing a blind test, could guess the Spectral Class of the star in question! Each class could be seen and ascertained with the eye, with each have only three or four shades of certain colours, with the solitary "non-colour" of white. The fourteen "valid" colours in this second system were (in order);
For double star observers such methodologies have been already established using scales like the Hagen Colour Index (HCI). This scale has values between -3 and +10, describing the possible range of fourteen double star colours - from blue to white to yellow to orange to red. This roughly mimics the range seen in astronomical spectra, the temperature of the star and the spectral classes. However the problems for double stars that use this particular index, finds the fundamental inherent weakness is a scale is that it does not differentiate between the different colour saturations. Furthermore it takes no account of the stellar magnitude. Although this scale is quite arbitrary between observers, different eyes will certainly see different colours. Unfortunately, the HCI system leaves too large a range of observable possibilities for the many different colours. Moreover, detecting colour is also very observationally difficult to see as the stars more often than not appear simply as point sources. Often by just simply defocussing the stars into small plate-like disks can be applied to partly exacerbate this problem.
When reading older books, texts and catalogues, you
will find more often that they not use the
following abbreviations W hite, B
lue, Y ellow, O range, P
urple, R ed, G reen, C grey,
L ilac, A gold, S ashy. With
the following additions: p ale - or d
eep and the tendency towards any colour -
sh. So as an example, a yellow star with the
colour not convincing - Ysh (Yellowish) or
A further usefulness of this colour scheme is that the observer can quickly write down these abbreviations in his or her observation notes. Although the use of colour is likely not important, but it is an additional descriptor when checking the pair at a later date or reducing observations.
Later use of the abbreviations now tend to favour the Hagen Colour Index (HCI), which relates closely to stellar surface temperatures. Using this index, visual observers should report as e.g. " -2 / 3", being a pale blue primary with a pure yellow secondary. Other additional colours were added later Ie. -0.5 for grey and -0.25 for green.
Figure 5. (On the Right-hand Side) gives the approximate look of the vast majority of star colours in the telescope. This is based on 10% Colour Saturation given earlier in the text.A. The White Box on the lefthand side of the Figure shows the Hagen Colour Index Number, the approximate observed apparent colour and the Spectral Class it pertains too.B. The White Box on the righthand side (at the top) is the reported colours sometimes seen by observers. I have labelled this as due to Contrast Effects because more often than not they are only seen in visual double stars.C. The White Box on the righthand side (at the bottom) gives the pure monochromatic colours as they would be seen in a telescope. These of course do not exist in Nature and are given as comparison.
If the colour is a definite colour, report it as eg."White" or "Blue" etc.
If the colour seems a definite tint, report it as eg. "Yellowish" or "Bluish" etc.
If it seems a combination or range of colours report it as "Bluish" or "Bluish-White" etc.
If the colour can not be described, record it as "Unusual" or "Colourless"
If the primary’s colour is seen but not the secondary, record it as "Blue / - " etc.
Interesting discussions often appear every now and then regarding the observation of green stars. This is especially prevalent in the observations during the 18th Century, relevant to observers like Admiral Smyth or Rev. T.W. Webb. In my view, the only star that I have really seen to display green was the companion to Antares / α Scorpii, which I thought was really closer to blue than green.
The challenge about the true existence of green stars was likely first eliminated by M. Minnaert “Light and colour in the open air.” Dover Publications (1954). If the colour green is real in stars, then I would suspect that might be caused by an optical defect of the telescope combined with effects of the eye. An similar example of this effect is what that occurs with visual observations of the planet Mars. For example, Raffaello Braga from the 33-doubles e-group ([email protected]) told that the;
“...companion of Pulcherrima (Epsilon Bootis) has been sometimes described as green. This is surely a contrast colour that may be perceived when the star is observed with obstructed telescopes, as they tend to diffuse light around the primary component...”
He also reveals, that according to Flammarion, other green stars included the companions of;
“...Zeta Lyr, Gamma Del and Alpha Her.”
Another “classical” green Example commonly described is often Alpha (2) Librae but, I know of no other far southern ones.
The only green I see in any astronomical body are associated with several planetaries and the brightest of the emission nebulae. Ie. The Eta Carinae Nebula (NGC 3372) in Carina or the Orion Nebula, and the outer planets of the Solar System Uranus and Neptune. This is either formed by ionic emission of O-III “forbidden” light or by interaction of light by chemical compounds like Methane.
My main disagreement with the existence of green stars is that the temperature range of these objects falls in the white "A"-type stars where green doesn’t appear in the spectrum of these stars. This is because all the other colours of the spectrum equally "swamp the light" like blue, yellow and red - hence the B-V colour index value of 0.0 indicating no colour excess.
The only possible way I can think possibly to
produce a green star is likely a close visual
binary star that has both blue and yellow
components in about 2:3 magnitude ratio. Then, the
combined colour would be certainly be green.
However, I know no examples of such objects.
I once did a rough search of suitable eclipsing binaries and even some ellipsoidal systems ("E-II’s"), and found only a handful of examples that met the criteria. However, all were far too faint for proper visual colour assessment.
I have read much about what is written about colour, and have found some interesting ideas that are worthy for elaboration and clarification. Below is an adaptation of some of my own notes and essays on colour, which I have slightly updated for relevance to astronomy and double stars.
One of the most interesting aspects is on the perception colour and the alleged differences between the sexes. Much of this has been generated by the fable that women have some superior vision and colour perception. The modern scientific view has shown there are no significant difference between males and females in interpreting colour and most of the current literature still confirms this view. Recently, colour scientists have shown that the main difference in colour perception between males and females to be more psychological rather than a physiological one. The reasoning follows that for women their mothers and peers trained girls in colour perception and colour matching, especially after puberty. Subjects deemed to have improved "perception" were merely based on a vastly better colour vocabulary. Important examples are in colours seen nylon stockings, lipstick and dress colour under fashion parade lighting. Naturally women, who are faced with applying face make-up, soon know the subtleties of colour and the match of cosmetics to achieve the effects they want. This is also shown in the comparison or matching of many additional fashion accessories and with their clothing.
Men in life are generally not faced with any degree of colour matching, and psychologically do not need or use such colour terminology. Others in this field of study say the need for women having the colour knowledge improves their "attractiveness" to their male counterparts. Some have said that certain colours, like red, are more noticeable by males. (Ie. Males more often see red on females rather than on other males because they are more aggressive likely from adrenalin and testosterone.) However, no physiological difference has ever been found to influence either the retina’s rods and cones to account for this. Another likely possibility suggests that colour may be someway affect by the individual’s emotional state. Again this is more likely an environmental difference. Another explanation maybe to do with brain chemistry and the interaction of with various compounds including hormones and adrenalin release. Though they have made some studies on such mechanisms our understanding on this subject remains quite incomplete. All eyes have the main chemical pigment known as 11-cis Retinal; the principle photo-receptor’s photosensitive chemical component that is not too unlike the silver halide crystals used in photography, that measure the light intensity. The 11-cis Retinal in the reaction combines with specific proteins, called amino acid glutamates, which then become the colour chemical "interpreters" for the photo-receptors. The human brain has acquired these latter proteins for colour discrimination and is some cases the erroneous recombinations for the wrong interpretation of colour in colour defects.
The main problem with colour perception between the sexes is with colour blindness. It is found that the so-called anomalous trichromacy that limits 6% of men’s colour vision, meaning they are unable to properly discriminate the colours between red and green. Another 2% are so-called dichromats, and are deficient in the pigments needed for discrimination of the both the long and middle wavelengths. Men are also ten times more likely to have some form of colour blindness defects than women. Most colour blindness is cause by a defect in a specific gene that causes in the eye by either the red or green cones called protanopia, or the less frequently known blue cone defect known as deuteranopia. Overall, visual colour problems are caused in the incorrect usage of the chemical pigments. In simpler terms, it works like a television where the colour gun is working incorrectly and, not targeting properly or even has one gun is not functioning at all. Ie. Take out the red component so the colours that are seen are mainly yellows, blues and greens etc.
Total Colour Blindness occurs in 1:40 000 individuals, equally between men and women, where the cones do not form from birth. Such persons are sensitive to high intensity light, and have vision that is akin to your surrounds as they appear during normal twilight vision. (Naturally without any colour) Sometime others have no rods, and have to rely on their cone vision. These individuals are "night-blind" are medically termed hemeralopes.
Another more general fault is that the spectral range of the visual wavelengths narrows as you age. The cause for this is likely that the rod and cones reduces in number combined with increasing inefficiencies in the chemical signals being sent to the brain. Although the visible impact is minute during the daylight hours because there is overwhelmingly sufficient amount of light, the effects become far more pronounced when less photons are available. Ie. If the colour degradation were 25%, for example, and then say some million photons were received in one second of time during daylight hours, the loss of light would be of little consequence as there is enough light available for colour discrimination. Yet if a hundred photons were received over the same period the effect would be more dramatic and obvious. To our eyes, this manifests in the gradual loss colour so that the sky would becomes more "greyish". (Note that if this postulate is true, this would have slightly more trouble discerning nebulosity in the telescope as we got older.) A second effect is that the range of colours also diminish such that the ability to see blues and reds at either ends of the visible spectrum becomes harder to see. As our eyes as sensitive to red, then you should find that the perceived blues intensity gradually gets slightly lesser over time. This combined with the decreasing light intensity will find that colours become less obvious. I suspect that the age where these effects start happens at an average age of about fifty-year’s old. (See Figure 5)
Figure 6 shows the expected explanation for most of the loss of colour vision as we age. Although arguably subjective, it does explain what is happening regarding the general discussions about colour perception with people of various ages. It is important to note that some people may experience no loss of colour at all while others may find the changes and differences suddenly and quite dramatic. Again there is no real "better" or "worst" in this situation and certainly no "superior" colour vision.
In nature, and this is still unexplained why this is so much more different from humans, many colour-visioned mammals and primates have known significant difference in colour perception between males and females. Typically males will have two types of colour cones dichromats while females have three colour cones or trichromats. The proposed reason for this has been something to do with either behaviour modification or in "mate" selection. [Some religious discussions have used these facts against Darwin’s "Theory of Evolution".],
Note: Only 2% of human males are dichromats - a genetic eye defect of misaligned X-chromosomes.
The chemical proteins for the coloured-cone photo-receptors are attached to the XX and XY. Interestingly women have a duplication of these cone receptors while males do not. This explains the increased number of males that have imperfect genetically colour vision. However this does NOT mean that females have, as some submissions I have read have claimed, of better or “improved” vision, as the chemical and physical mechanisms are just the same. In evolutionary terms, our eyesight maybe one of the earliest to develop especially as keenness of sight has a definite advantage for hunting animals or spear fishing for food.
Colour genetic defects in women may mean they can be so-called tetrachromatic, which are likely women who have had sons who are “dichromats”. (Jordan, G, Mollon, J.D. “A study of women heterozygous for colour deficiencies.”, Vision Research, 33, 1495-1508 (1993)) Here, they mismatch the colours, and they have slightly better capabilities in separating red to orange colours. However, such women are literally one-in-a-million.
1. Malin, David; “The Colours of the Galaxies”, Pub. Cambridge University (1996)
2. “Colour, Art and Science.” Ed. Trevor Lamb and Janine Bourriau, Cambridge University Press. (1995)a. Baylor, Denis; “Colour Mechanisms of the Eye”;3. Gerstner, K.;“The Forms of Colour- The Interaction of Visual Elements.”; MIT Press (1986)
b. Millon, John; “Seeing Colour”
c. Lyons, John; “Colour in Language”
I would like to sincerely thank Tom Teague, Luis Arguelles, Eddy O’Conner and Raffaello Braga for their poignant views and for being the true inspiration for this text on this page. However, Richard Harshaw deserves special credit for some really interesting ideas and innovative solutions regarding the colours seen in doubles. One or two ideas by Richard have shown pure genius and have forced me to question for some time on how to apply it to stars.
Note: All of the above are members of the unique 33-doubles Yahoo! Group.
1. The definitions of the primary parameters of colour are hue, saturation and brightness. This is where hue is the dominant - as Wien’s law dictates for star. Saturation is the observed degree of whiteness, while brightness is the intensity of the observed light.
2. The title of much of the earlier section on green stars I have updated, which appeared in the 33-doubles e-group entitled “It’s Not Easy Being Green”. I commented “In regards the colour Green, perhaps Kermit the Frog is the only being, in this world, who sees these green coloured stars with certainty? (Hence the title...”
3. I been thinking of proposing an experiment using a series of stars in increasing Right Ascension, in which the observer has to estimate the colours, and this is later correlated with the B-V values. This will give an estimate of the observer’s ability to see colours, and even shades of those colours. It would also test the colour acuity of the observer, objectively. Would anyone be interested in such a visual experiment?
4. have some Double Star Colour Estimate results of the seventy-two stars observed by some thirty-two amateurs of the Astronomical Society of New South Wales and other nearby Australian astronomical Society’s. We conducted these, equally among a few northern and many southern pairs. (See Page029d.htm)
5. Luis Arguelles (33-Doubles Communication) commenting on this suggests;“...as commented by other members of the list, probably it was caused from different cultural roles between males and females. I also think it’s more a question of brain processing than the number of cells in our retinas.”
6. Ric Hill (33-Doubles Communication Message 835: 05th April 2000), was the one who inspired some of the text above. However, there is no evidence to support his quote below;“Yes, I remember reading that during WWII a study was conducted by DOD, to determine which were better suited for night watch duty. I can’t remember the source, possibly Science News but if it was then it was from the early 1990’s, or maybe the late 1980’s. Basically, it found that women see colour at a lower light level than men but men can see in an overall lower light level than women but it’s all black and white to us. So if you want to see faint galaxies, be a guy. But if you want to see colour in the Orion Nebula, be a gal. Sorry ’bout that folks, nature is sexist.”
7. I have studied chemistry and worked for a biscuit company for some sixteen years before leaving a few years ago. During 1989, one of my projects was to the set-up for the instrumental measurement of the colour of baked biscuits. I was already fairly interested in colorimetry sometime before this, and actually once did a specific course on colour including colour matching and design. Of course of the seventeen in the class I was the only male, mainly because they designed the course for textiles, cosmetics and fashion. A small portion however was left under architectural design, which I enjoyed the most, but I unfortunately missed a couple of these lectures. Much of the earlier work presented was on colour measurement (colorimetry) and on the creation and nature of pigments. Once I completed the course, I am now considered a colourist, though over the years I have never called myself this. This is mainly because others have often interpreted the connotations of the title, by me presumably being able to improving there lives by advising matching certain colours to their personalities - the ’astrology’ of the colourist. This knowledge, however, has proved to have certain advantages especially with the opposite sex. Ie. Drumming up a conversation, but I have observed, despite my continued advice, most of them still take absolutely no notice! Furthermore, I still continue to wear the “standard issue” black trousers with bright coloured tops and jumpers - and never as the current and costly fashion dictates.