Part 3: Colour – Initial thoughts and reading around colourPosted: June 2, 2011
Part 3 : Colour – Some Initial thoughts and reading
I set out on Part 3 with with some questions in mind. How do we see colour; do different people have different responses to it; what happens when people are colour-blind and how might this affect them as photographers, also how is our emotional response to colour affected by our culture as well as our physiology? I read around it all and did some research but am now attempting overall to keep it as simple as possible for myself. This curiosity about colour and colour perception was intensified when I read about the difference between saturation and brightness in the workbook whilst preparing for the first exercise on colour. I decided I need to understand more.
The effect of colour
Colour works on 3 levels. They are: Visual – this is the objective, immediately obvious level; Expressive – the emotional level, evoking sensations that are often subjective and non-visual; Symbolic – the cultural level, where certaincolours and combinations are associated with things that we have been brought up with. (Basic Colour Theory, Course Supplement). Individual colours have a variety of cultural associations such as national colours (as in flags), and the use of white (weddings in Western cultures and funerals in China). The same colour may also have different associations within the same culture at any time, e.g. red for danger with its connotations of blood, but also for romance/passion.
The earth’s colours change from one season to the next. Grasses change their hue and sunsets differ in intensity and hue. Generally winter flowers are more subdued than summer flowers in both blossoms and leaves. This means that colours can be used differently to evoke a feeling of one particular season or another. Nature routinely uses several color combinations. Flowers tend to have mono-chromatic, analogous and complementary colour schemes. Leaves are more apt to use a mono-chromatic or analogous colour scheme.
Analogous, split-complementary and complementary colour schemes are often displayed in sunsets and sunrises. The ocean, lakes and other bodies of water appear monochromatic or analogous unless a sunrise’s or sunset’s hues intermingle with them. Warm colours are associated with sunlight, heat, excitement and happiness. They have more ability to be luminous than cool colours do. Warm colours advance visually , for example red in the forground can enhance sense of depth. Yellow, the brightest of colours, has obvious associations with sources of light. Cool colours tend to recede into the distance, for instance blue recedes more than yellow. Its primary symbolism derives from its occurrences in nature – the sky and water. Manipulating adjacent hues can make any colour register as either cool or warm.
The human’s eye ability to distinguish colours is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. The message is passed to the optic nerve and then on to the brain. Humans are trichomatic which means that the retina contains three types of colour receptor cells – cones of which there are about 6 to 7 million.. One type is most responsive to light that we see as violet (wavelength around 420 nm) and this is distinct from the other two which are closely related both genetically and chemically. Red cones are most sensitive to light we see as greenish yellow (wavelengths around 564 nm) and green cones are most sensitive to light perceived as green (wavelengths around 534 m).
The other type of light sensitive cell in the eye is the rod, of which there are about 120 million in the eye.. The rods are more sensitive thant cones, but sensitive to low light, not to colour and they perceive images as black, white and different shades of grey, responding better to blue light than red. The cones, which require a greater intensity of light, are sensitive to colour. When the light is bright enough to stimulate the cones the rods play little part in vision. In dim light, when the cones are understimulated, leaving only signals from the rods and this leads to a ‘colourless’ response. These effects are described in the Kruithof curve that describes the change of color perception and ‘pleasingness’ of light as a function of temperature and intensity.
“…the color of an object is a complex result of its surface properties, its transmission properties, and its emission properties, all of which factors contribute to the mix of wavelengths in the light leaving the surface of the object. The perceived color is then further conditioned by the nature of the ambient illumination, and by the color properties of other objects nearby, via the effect known as color constancy and via other characteristics of the perceiving eye and brain.”
Combinations of cones are stimulated when we see perceive a colour that has a wavelength between that of the primary colours red, green and blue this results in our being able to detect light of all colours in the visible spectrum. I’m thinking of a rainbow here.
So far I have understood that the perception of colour is mainly due to the absorption and scattering properties of whatever we are looking at being different from the incoming wavelengths of light that illuminate it. There are other effects in the mix. For example, we see green leaves as green because leaves and other green plants use chlorophyll to change light into energy. Chlorophyll absorbs the red and blue colours of the spectrum and reflects the green. The cones and rods of the eye pick up on this particular wavelength and frequency of green and send the message to the brain.
Differences in Colour Perception
One website that I looked at states that if we lose our eye sight the body adapts and receives colour rays through our skin, but I couldn’t find any other references to that. Another website described a lady who lost her eyesight and then became a painter. It quoted her as saying that she painted from memory and distinguished the different colours of paint by dipping her fingers into the paint because each colour had a different texture which she could feel.
I wanted to find out whether everyone sees colours the same. Certainly my husband and I often disagree as to whether a colour is blue or green, M. Freeman (2007) also comments that many people have difficulty in judging the colour of blue precisely. Certainly, as I have become older I’ve needed more light to see clearly, so presumably age affects the rods and cones in the eyes and therefore their response to wavelengths of light. I found a brief report on a 2010 Project, “Do you see what I see”, which was presented at the California State Science Fair. The hypothesis was that people see colours differently, especially as they age. The method involved an LED light box, consisting of two different coloured lights, red and green, each separately controlled. The red light was set to a constant colour as measured by the DMM and subjects were asked to adjust the green LED in such a way as to produce a third colour. The voltage of the green LED was then measured to determine an individual subject’s colour perception. The DMM reading of each subject was placed on a graph and plotted by age and gender. It was shown that in both genders, as a person ages, the DMM measurement gets higher, which means they see colours as duller. In particular, the colour perception of men decreases significantly past the age of 45. Although colour perception also changes in women as they age it is not as significant as men. The results also show that male and female colour perceptions differ from each other slightly when younger. This was an interesting experiment but, unfortunately the Project Summary didn’t give information on how many people were tested and the other necessary information to establish whether the experiment was scientifically valid.
People who suffer from colour-blindness have less numbers of particular cones than normal which means they get colours confused. There are different types of colour blindness the most common form being red-green. I am particularly interested in the effect of colour blindness on photographers and how that impacts upon their photography.
One of my fellow students linked me to a relevant Flickr site which I found fascinating. One of the discussion threads was, “ what makes a colour-blind photographer or hobbyist different from others?”
Photographers commented on such areas as basing photographs on feelings and composition and not colour; more easily understanding the abstract nature of black and white; being more sensitive to differences in tone and that being colour-blind helps to get tones and contrasts just right.
I liked the effects of their images. With many of them I could see a difference in the tones, in both black/white and colour which I find difficult to describe – something slightly duo-toned/de-saturated, maybe more on the low-key side and, in the black and white, more of a hint of sepia which I imagined might be due to a particular use of filters. Even with HDR effects I found the images more calming to my eyes. I’ve joined the group because I find the images very interesting and maybe in time and with more knowledge/experience I’ll be able to work out the differences more precisely.
This has been a brief summary of my reading around colour to give me a starting point on Part 3. I’m going to return to this as I carry out the various Exercises, particularly the use of colour in photography and how this can be used symbolically and to evoke particular emotions/sensations.
1st June 2011
“Basic Colour Theory”, Photography Course Supplement
Freeman, M, The Photographers Eye, 2007
Wilcox, M, “Blue and Yellow don’t make Green”, 1987, Artways, Perth, W. Aus
Wolfrom,J, “Color Play”, 2000, C & T Publishing, California