Controlling the strength of colour

For this first exercise in Part Three : Colour, the idea was to find a definite colour and take a series of five photographs. All five photographs needed to be composed exactly the same but differently exposed from bright to dark. I chose an outside orange coloured wall providing a rich colour to work with and used a Canon EOS 500D. The images are set out in sequence below starting with the lightest :

P219: f5/6 @ 1/200  ISO 100 37mm

P220: f6.3 1/200 ISO 100 37mm

P221: f7.1 @ 1/200 ISO 100 35mm

P222: f 8 @ 1/200 ISO 100 37mm

P223: f9 @ 1/200 ISO 100 35mm

From what I can see, P223 which is the most underexposed,is the darkest version of the original starting point (P222);the most overexposed image being P219. The hue ranges from orange ( P223- P221 ) to yellow ( P220-219). Saturation varies from pure ( P223) to intense ( P222) to saturated in images ( P221-P219 ). Brightness alters almost in line i.e. slightly dark where the saturation is pure (P223).In P222 where the saturation is intense, brightness is average as it is in P221 and P220 both saturated colours. In P219 brightness is 'bright' where the colour is also saturated.