Black & White Films- Look Real Life- Colour Blind?
Discussion
TheHeretic said:
Did you guys know that some people can see in ultra violet, (or at least claimed they could... It was a while ago I saw the program).
Apparently we all can potentially, the retina is sensitive to uv but it's filtered out by the lens. Those people who started to see in uv had replacement plastic uv transparent lenses fitted in their eyes.It's thought we don't as we are so long-lived, the uv would cause permanent damage to our eyes in a few years. Many animals see in uv, their life-span is shorter than the permanent damage time so it's not an issue.
Shaolin said:
Apparently we all can potentially, the retina is sensitive to uv but it's filtered out by the lens. Those people who started to see in uv had replacement plastic uv transparent lenses fitted in their eyes.
It's thought we don't as we are so long-lived, the uv would cause permanent damage to our eyes in a few years. Many animals see in uv, their life-span is shorter than the permanent damage time so it's not an issue.
My gran's second husband was an astronomer, and after a cataract operation, he found he could see into the ultra-violet spectrum, which meant a whole new range of sights was opened up when he looked at the stars. It's thought we don't as we are so long-lived, the uv would cause permanent damage to our eyes in a few years. Many animals see in uv, their life-span is shorter than the permanent damage time so it's not an issue.
BuzzLightyear said:
I have red/green/brown colour-blindness although fairly mild as far as I can tell as it's a difficult thing to quantify (lab tests may be able to?).
Even so, I can usually tell the difference between red, green and brown fairly well unless the shades are muted. For example, an apple, a tomato and soil are patently green, red and brown to me but the upholstery of the chair I am currently sitting on could be green or brown to my eyes (but is not red).
However, somewhat strangely, when I was little, my sister and I had matching cups but one was pink and one was blue. The shades were similar and I couldn't tell them apart.
Even more strangely though, I can see variations in shade which people with "normal" colour-sightedness, can't. A relative bought a mix and match suit where the jacket and trousers appeared to be two different colours to me but nobody else could see it. Our kitchen doors are different colours to the frames to me but everyone else sees them as matched.
Does that help???
Eh? You can't be brown colour blind! Red and green yes. Colour blind people have faulty colour receptors usually the red and green ones (there isn't a brown receptor). This means that the colour red or green is not perceived as strongly as any other colour. This also includes any colour that may be made up with red or green like purple or brown! So colour blind people see purple as blue and brown as green, there are of course many other varations. The severity varies too and can be tested for.Even so, I can usually tell the difference between red, green and brown fairly well unless the shades are muted. For example, an apple, a tomato and soil are patently green, red and brown to me but the upholstery of the chair I am currently sitting on could be green or brown to my eyes (but is not red).
However, somewhat strangely, when I was little, my sister and I had matching cups but one was pink and one was blue. The shades were similar and I couldn't tell them apart.
Even more strangely though, I can see variations in shade which people with "normal" colour-sightedness, can't. A relative bought a mix and match suit where the jacket and trousers appeared to be two different colours to me but nobody else could see it. Our kitchen doors are different colours to the frames to me but everyone else sees them as matched.
Does that help???
What has always fascinated me is how and when people realise that they are colour blind. Up until that point, X hue is green, Y hue is red etc. How do I know that what you all see as orange, appears the same to me? It's still a distinct hue that I know is characterised by the fruit, but that's as far as it goes.
A bit Keanu Reeves, i realise, but individual perception and subjectivity like that is intriguing.
A bit Keanu Reeves, i realise, but individual perception and subjectivity like that is intriguing.
dibbers006 said:
Ian974 said:
5G I'm not sure if I'd call green or a dull yellow.
2F. Brown? Green? Browny-green-red? It's a colour, and I can see it, but I have absolutely no idea what to identify it as.
2F is a strange colour. Placenta red does actually seem like the most fitting description! Definitely not green though.
I am really struggling to get a handle on your (the Colour Blind) perception of colours and what ones are more difficult. I cannot fathom why 2F is an anomaly.
xRIEx said:
I know I'm off course as this is about colour blindness, but from a photographic point of view there is not necessarily a 'correct' way of processing black and white film: it can be overexposed and underdeveloped (or vice versa) to change the tone and texture of the photograph (this can be doubled as there are two exposures: the negative and the print).
Also, colour filters affect the light that hits the film when the photo is taken; a classic example is a red filter giving dramatic skies.
Yes, I'm not sure of the correct terminology to what I am referring. I deal with images a lot and a raw black and white image is always preferable to a desaturated colour one. From somewhat the distant past of black and white and colour photographic film. Dedicated Black and White always gave a better shot. But I don't know how to describe the exact difference. (Which is embarrassing really as I can visually appreciate contrast, vibrance etc)Also, colour filters affect the light that hits the film when the photo is taken; a classic example is a red filter giving dramatic skies.
Famous Graham said:
What has always fascinated me is how and when people realise that they are colour blind. Up until that point, X hue is green, Y hue is red etc. How do I know that what you all see as orange, appears the same to me? It's still a distinct hue that I know is characterised by the fruit, but that's as far as it goes.
A bit Keanu Reeves, i realise, but individual perception and subjectivity like that is intriguing.
It's an interesting question - so 'orange' to me may appear in my brain as the same colour as 'green' is to you, (maybe everyone has the same favourite colour but call then different names...?). A bit Keanu Reeves, i realise, but individual perception and subjectivity like that is intriguing.
I seem to remember there being something on mythbusters or similar that went into this and explained how red is actually red to most people for example, can't think how they did it though...
silvagod said:
You lot should go work in the paint shop of a motor manufacturer. After having spent 10 + years in the motor trade (albeit a long time ago) I have no understanding how they come up with the names for the colours of cars. I know it's personal interpretation to a point, but some of them baffled me!!
I think the names are mostly b
ks, but have to be sufficiently different to other paint names so they can be trademarked (or registered/copyrighted/whatever, I don't fully understand the differences). It is not possible to trademark 'Red', but 'Candy Apple Red' is absolutely fine.Absorption spectrum of human cones:
You can see that the cones overlap in the spectrum, in particular yellow light is of a wavelength between red and green (forget what you learnt from mixing paint...). The cones in isolation can't report the wavelength of the light they are "seeing", I'm sure someone more learned in the field will correct me but the way I like to think of the system is that it is akin to reporting a score based on where the wavelength lies in the cone's part of the spectrum. So green cones will report a higher score for green light, and a lower score for both yellow and blue light. The brain assigns a final colour based on the combination of all three types. For example, if the red and green cones report a particular balance of scores but the blue cone reports nothing, the brain works out that the colour must be yellow. If all three detect light, the colour is determined to be white. In simplistic terms if you only had, say, green cones, then the brain would be unable to distinguish colours either side of green from each other. How the brain actually draws this is difficult to determine - for example it might assign one or the other but the individual couldn't tell you which one.
The reality is that most colour blindness is a shift in the sensitivity range of one of the cones, e.g. the spectrum of one's green cones is shifted towards red. The result is that certain shades of red and green appear similar. This is deuteranomaly, a form of anomalous trichromacy and the most common form of colour blindness which affects a fairly high proportion of males. For other people, one or more cone types is entirely deficient. This is dichromacy/monochromacy. For example if your red cones do not function, red things will appear dark because as far as your brain is concerned, the object is not reflecting light. Arguably the cone you can most "do without" is green.
I don't know much about about it so take this with a pinch of salt, but I would naively theorise that the particular spectrums that our cones detect influences how we see colours. For example, one doesn't see "reddish green" but "bluey green" is definitely something you hear people say - and disagree on. If we had a cone that detected wavelengths in between these colours (and the brain updated its algorithm to match of course), perhaps these shades would appear very different to each other and bluey green would be as different a colour from either blue or green as blue is to yellow... Some animals do of course have more types of cone, sometimes they are there to detect wavelengths outside the range humans can see, other times they just make it easier for them to see the difference between the colours.
It gets even more complicated when you start to think about the differences between mixing light (e.g. how images are represented on a computer screen) and mixing pigments (e.g. how they are printed). Basically, mixing pigments affects not just the wavelengths of light reflected, but how much light is reflected. That's why mixing many colours of paint gives you brown and not white. Also the more colours you use to print with, the greater the range of colours/shades you can represent. The "standard" cyan/magenta/yellow/black setup actually leaves huge deficiencies in the range of printable colours, and bright colours in particular simply cannot be printed - they are actually converted to duller shades.
You can see that the cones overlap in the spectrum, in particular yellow light is of a wavelength between red and green (forget what you learnt from mixing paint...). The cones in isolation can't report the wavelength of the light they are "seeing", I'm sure someone more learned in the field will correct me but the way I like to think of the system is that it is akin to reporting a score based on where the wavelength lies in the cone's part of the spectrum. So green cones will report a higher score for green light, and a lower score for both yellow and blue light. The brain assigns a final colour based on the combination of all three types. For example, if the red and green cones report a particular balance of scores but the blue cone reports nothing, the brain works out that the colour must be yellow. If all three detect light, the colour is determined to be white. In simplistic terms if you only had, say, green cones, then the brain would be unable to distinguish colours either side of green from each other. How the brain actually draws this is difficult to determine - for example it might assign one or the other but the individual couldn't tell you which one.
The reality is that most colour blindness is a shift in the sensitivity range of one of the cones, e.g. the spectrum of one's green cones is shifted towards red. The result is that certain shades of red and green appear similar. This is deuteranomaly, a form of anomalous trichromacy and the most common form of colour blindness which affects a fairly high proportion of males. For other people, one or more cone types is entirely deficient. This is dichromacy/monochromacy. For example if your red cones do not function, red things will appear dark because as far as your brain is concerned, the object is not reflecting light. Arguably the cone you can most "do without" is green.
I don't know much about about it so take this with a pinch of salt, but I would naively theorise that the particular spectrums that our cones detect influences how we see colours. For example, one doesn't see "reddish green" but "bluey green" is definitely something you hear people say - and disagree on. If we had a cone that detected wavelengths in between these colours (and the brain updated its algorithm to match of course), perhaps these shades would appear very different to each other and bluey green would be as different a colour from either blue or green as blue is to yellow... Some animals do of course have more types of cone, sometimes they are there to detect wavelengths outside the range humans can see, other times they just make it easier for them to see the difference between the colours.
It gets even more complicated when you start to think about the differences between mixing light (e.g. how images are represented on a computer screen) and mixing pigments (e.g. how they are printed). Basically, mixing pigments affects not just the wavelengths of light reflected, but how much light is reflected. That's why mixing many colours of paint gives you brown and not white. Also the more colours you use to print with, the greater the range of colours/shades you can represent. The "standard" cyan/magenta/yellow/black setup actually leaves huge deficiencies in the range of printable colours, and bright colours in particular simply cannot be printed - they are actually converted to duller shades.
Edited by bogwoppit on Wednesday 7th March 10:33
John Kay - the singer from Steppenwolf - is totally colour blind.
He suffers from Achromatopsia
http://en.wikipedia.org/wiki/Achromatopsia
http://www.achromatopsia.info/john-kay-achromatops...
He suffers from Achromatopsia
http://en.wikipedia.org/wiki/Achromatopsia
http://www.achromatopsia.info/john-kay-achromatops...
Gassing Station | Science! | Top of Page | What's New | My Stuff