Advanced Technique & Process 2A: White balance testing

13th November 2014

Equipment used

Nikon D7100
Tripod
Incandescent light source (HMI discharge)
LED light source
White card
Colour card

The aim in this session was to test out the pre-sets of white balance within our DSLR cameras, and note the effects it had on the colouration, highlights and shade and contrast of our images. We set up a variety of different light sources and tested using the same pre-sets on each light. All light sources are measured in degrees Kelvin – the colour of the light – and this is dependant on how much the light ‘burns’ – because the warmer it burns, the higher the Kelvin degree of that bulb/source. This works visa versa – the ‘cooler’ the light source the lower the Kelvin degree.

The first set up was a ‘Red head’ (large incandescent light) bounced onto a white board (with blue writing on it), on to the subject, creating a Rembrandt style lighting on the subjects face. This kind of light source got really warm really quickly because it literally burnt inside the bulb like a fire to give a warm ambient tone. Without changing the exposure, we took an image on each of the following pre-sets and took a shot:

The second set up was a ‘cold’ light source – an LED light head with a soft box attachment. This light is on at a constant and doesn’t flicker/dim or get warmer, it is almost the equivalent to day light. We had this light source head on to the subject, and the background behind the subject was Tungsten lighting (from the regular lights from the ceiling). We tested the pre-sets to see how they differed from the last set up…

The third set up was interesting because we used the daylight coming in from the window as the ‘backdrop’ and used the ‘cold’ light source to light the subject. We wanted to balance out the 2 ‘daylight’ sources but also test setting Custom white balance in camera, exposing using a white card and then a colour card, to then test the pre-sets on the colour card and see what the outcomes were.

White card test exposure:

DSC_1992RESIZED DSC_1993RESIZED DSC_1994RESIZED

I exercised custom white balance in camera, using a white card, then saw that the colour of what the subject was wearing had a big impact on the colour cast: the mustard colour top gave the image a yellow tone, and the grey/bage cardigan gave a blue/grey tone to the image (with the day light light behind and in front of the subject.

Pre-sets with colour card:

Notice how the colours on the card appear different on each shot because of the different pre-sets?

I found this session really interesting to see how the different light sources and their scientific behaviours affected the actual appearance of the light itself, and then how the pre-sets all gave the different sources different tones and colours, also working with the subject and how skin tone and colour of clothing also affected the Custom white balance setting. I definitely need more practice setting Custom white balance in camera, and using my own camera and grasping how these pre-sets work for my model and to test it in different lighting situations.

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