Monday, 23 May 2011

Colour: Project - Building a library of colours

Exercise: Primary and secondary colours

Aim:  The aim of this exercise is to take images dominated by a single colour from the colour wheel, vary the exposure (over and under) and then select which is the closest match to the colour wheel.

Approach and results:

The exercise suggests changing the aperture to get the different over/under exposure.  When taking pictures where a colour fills the frame you are usually close or zooming in.  Either way you will generally have a fairly shallow depth of field.  Altering the aperture rather than the shutter has a more noticeable effect on the image.  I altered the shutter for the violet pansies as I was so close that the depth of field would be lost.  I was working with a shallow depth of field anyway as I needed to capture the flowers without motion blur created by the breeze.

Metering – the evaluative meter is ok if the colour fills the frame.  If the colour fills part or even the majority then the spot meter is better, especially if the other elements in the frame are of a distinct difference in brightness as the evaluative metering starts to compensate.  The orange tulips are an example of this.

 The results varied due to the metering on the camera and shrinking the images for the blog has made many of them look the same.  My preferences are as follows;

Yellow - overexposed.  This was closest to the real thing.  The large area of yellow (naturally bright) has caused the camera to underexpose.
Orange - correct exposure.  Over exposure produced false colour.  Under exposure lost the original brightness.
Violet - Underexposed - To keep the depth of colour the underexposed shot was most accurate.
Red - Overexposed.  Here the camera has compensated for the bright tomatoes and bright background by under exposing.
Green - Correct exposure.  A wide range of greens and more varied brightness has resulted in an even exposure.
Blue - Underexposed.  As a transparent subject with quite a lot of white reflections this looked more accurate underexposing, keeping the depth of colour.

The main learning point is that the brightness of the colour determines how the scene is metered and this needs to be taken into acount when taking the final shot.  I have experienced this when shooting in woodland and finding the camera wants to brighten the scene all the time.  I generallt need to underexpose to recreate darker scenes.

Interestingly it is the brighter colours from the colour wheel that benefitted more from overexposing to maintain the brightness and the darker colours that benefitted more from under exposing to keep the original depth of colour.

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