Find a strong, definite colour – a painted door for instance – and choose a viewpoint so that the colour fills the viewfinder frame. Find the average exposure setting […] Then take a sequence of pictures; all composed exactly the same, but differently exposed from bright to dark.

Arrange the […] images together . Apart from the obvious fact that the […] photographs vary from over-exposure to under-exposure, what other difference is there in terms of the colour?

– AOP Coursebook.

The photos that follow were all taken on a sunny afternoon in my back garden using my D50 with a 35mm 1:2 AF lens on it. They are of a Camden Council recycling tub that I’ve used as a laundry basket ever since I moved north of the river at the turn of the century. There are seven pictures rather than five, because it was only a few weeks ago that – playing with the various menus on my camera – I realised that I could set the increments by which exposure compensation worked at anything other than 1/3 of a stop. Further evidence if it was needed that you can never spend too much time playing with your camera…

All h-s-l values were calculated in Photoshop Elements 6 for Mac and were based on the centre of the embossed cross.

From looking at the the pictures, I can see that the lightness (brightness in Adobe-land) does indeed decrease quite dramatically as the sequence goes on; the saturation likewise increases and the colour temperature (hue) moves up from being closer to cyan to a much more obvious blue and end almost in the region of violet. The truest blues seem to be in the three pictures starting with the one shot at the meter reading and continuing into slight underexposure.

Likewise, doing the same thing with a red storage tub and a yellow council grit container showed similar results, although the red showed a slight drop off in saturation below an average exposure and yellow seemed most saturated either at average or slightly higher.

I’ll have a go with some pictures containing more than one colour, to see if I can emphasise a particular colour by choosing the correct level of under (or over) exposure while reducing the impact of the others.

(Postscript – I have also played with one of the standard exposure pictures and have found that  – providing the highlights or the shadows aren’t clipped – a raw image can be moved up and down the exposure range in Lightroom, creating the same colour effects to my eye as can be created in camera by altering the exposure; another thing to try while editing, I guess …).