We define colour by hue, saturation and brightness, each individually effecting the overall appearance of the colour, including white balance. Hue is the basis of colour with red, green, blue and yellow the unique hues, these are considered unique as they are the colours the human eye considers to be pure without the mixture of other colours. The hue can be altered with the use of white balance and more specifically the source of lighting in the photograph, or by using filters. Saturation is the colourfulness when comparing it to its own brightness. This is achieved by altering the amount of grey in an image, which has the effect of changing the colour to be more intense and vivid with less grey and rather dull or feeble with more grey. While saturation is more controllable with post production the brightness of a colour, which is relative the to amount of black and white in an image is easily effected in camera with the adjustment of the exposure.
I think understanding colour and the slight and often important differences it has on an image is something that comes with time and experience, being able to correctly expose and bring what it is out of the colour in the image first time. When looking at the images next to each other it is very clear to see the different effects the adjustments in exposure. Firstly in the image at +1EV the added white has given the image a lift, the lighter tones and overall brightness is obvious when compared to the darker images where the colour itself has turned into a darker orange, this difference at both +1 and -1EV are more apparent within the darker image, something I feel is attributed to the basis of the colour itself, in this case orange. When looking at the images and comparing them to what I saw I feel that the +1EV exposure was in this case the more faithful to the original.