As discussed in the text, green is easy to find, although a pure green is as rare as a pure red, yellow, or blue. In the image below I selected as neutral colored a patch of grass as I could find. The orange comes from a shop fronts painted surface. In this case I was very careful to establish correct exposure as the camera automatically heavily overexposed the subject and significantly muted the fieriness of the hue. The final hue, Violet was hardest to find, some flowers provided the nearest hue that I was able to discover (in this case I maintained focus to ensure that the green of the stems did not mix into the violet of the petals).
In this case the most accurate representation of Orange is the middle image (Where I carefully set the exposure), likewise with Green. In the case of the Violet, the under exposure by one stop is correct. The green as suggested is nowhere close to a neutral green, the pure spectral colour is far brighter and intense than is found in nature, or at least in nature in temperate regions.
Once again I have built a palette of what I think are pure colours, mixing is not so easy with RGB
Green is RGB = 0,255,0, Orange is RGB = 255,127,0, and finally Violet is RGB = 127,0, 255. Admittedly, these are far to bright, mixing pixels is different from mixing light or pigments.
Once again better colour renditions came from my Autumn shots
I have to admit, I have found this exercise rather frustrating, accurate colour reproduction is a stepwise process that begins with selection, but does not end there. The human brain is quite capable of white balancing itself. I have experienced this when diving, if I spend too much time looking at the review screen on my camera underwater and then look away, the reef takes on a distinct red tinge for a few seconds, then my brain rebalances. In any circumstance perception of colour is highly individual and strongly influenced by the environmental conditions prevailing.
Accurate colour management and reproduction is straightforward:
- White balance the camera to the light relfected by a gray card
- Set an incident light exposure reading and lock the camera into fully manual mode
- Edit photos on a colour calibrated screen
- Print to a colour calibrated printer