Judging Colour Temperature (Part 1 and 2)

The aim of this exercise was to get us to start thinking about the white balance (WB) setting on the camera and how this can be used to "colour" the photograph. This is a useful exercise if you shoot predominantly in jpeg format as you let the camera do the work and the thinking at the time of shooting. If, however, you prefer to use RAW files, then it should be noted that white balance settings can be adjusted post shooting at the processing stage. To maximise the learning of this exercise I have accordingly used jpgs taken by the camera (as opposed to my usual habit of shooting RAW)

 

I have combined the 2 parts of the exercise into a combined exercise. The brief was to take initially 3 photos with a WB daylight setting at different times and/or locations: one in full sunlight, one in shade and one at a time of the day when the sun was close to the horizon- I chose sunset). The second part of the exercise was to alter the WB setting to "shade" and then Automatic and then identify and assess the different colour temperatures.

 

As mentioned above, I have combined the 2 parts of the exercise and have arranged the photographs in 3 separate sections: Full sun; shade and sunset. Within in each section the photos will be set out according to their respective WB settings of  custom (my own based on setting the WB using a white card in situ), auto, daylight and shade. I would add that I used spot metering and set the camera's picture style to "portrait" mode. I used a canon 5D mkii and the 100mm L macro lens. I shot in Aperture Priority mode and the settings are set out in each picture.

Full Sunlight





WB: Custom; f 11.0; shutter speed:1/250; ISO 100
I used my own custom setting for the white balance in this shot.  You can see that skin tones appear natural and fairly neutral. I deliberately chose a light terracotta background which easily changes colour to orange or pink depending on the WB setting. In custom mode the background colour is reflected accurately but skin tones appear  less accurate than expected (it seems that they have a yellowish tinge and this may well be due to the colour of the light at the time of day) and perhaps not the most flattering; and due to the time of shooting (around midday) the photo is very contrasty and shadows appear harsh and unflattering. The light also makes it difficult for the subject to keep their eyes fully open.

 

WB: Auto; f 11.0; shutter speed:1/250; ISO 100
Using Auto WB setting in full sunlight has produced a softer picture but the colour rendition is not accurate. Skin tones appear washed out and the background has been rendered less accurately and has taken on a more salmon colour. again due to the time of day the photo has harsh contrasts and the subject's hair colour is subtly different from the custom WB. 

 WB: Daylight; f 11.0; shutter speed: 1/320 ISO 100

The daylight setting has rendered the colours slightly more accurately than Auto WB but they are still biased towards a red/ pinkish hue. Again the hair colour is subtly different from the custom WB setting but the background colour appears the most accurate  in hue, even above the custom WB setting which had rendered tones slightly yellow.

 

 

  

WB: Shade; f11.0; shutter speed: 1/200 ISO 100

The shade setting has created a photograph with the least contrast of the 4 but has given the photograph a distinct orange hue. this can be seen in the skin tones and particularly in the hair as it now appears ginger.

In full sunlight the best setting to use appears to be the camera's daylight setting. even using a custom WB setting has created difficulties with the colours being biased towards yellow. Auto WB is biased towards red and the Shade setting towards orange.

Shade

WB: Shade; f 11.0; shutter speed: 1/20; ISO 100

Colours appear accurate and somewhat richer. Contrast in shade is less pronounced and harsh shadows are minimised.

WB: Daylight;  f 11.0; shutter speed: 1/20; ISO 100

Daylight setting in shade whilst still rendering colours well, tends to  bias towards the red creating an unrealistic pink skin tone.

WB: Auto;  f 11.0; shutter speed: 1/20; ISO 100

similarly to daylight setting in shade, auto WB is biased towards the red end of the spectrum and it too creates unnatural skin tones.   

WB: Custom;  f 11.0; shutter speed: 1/20; ISO 100

On this occasion the custom WB setting has rendered colour much the same as the shade WB setting. colours appear accurate and natural if somewhat less saturated than the shade setting.

Sunset

 

 

WB: Auto; f 11.0; shutter speed: 0.3 sec (hence the blurring) ISO 100

unfortunately this shot suffers from blurring due to camera shake. the shutter speed was too low and whilst the image is accurately exposed it is blurred. Blurring aside the colour rendition of Auto WB can still be assessed.  This set of photographs was taken at sunset  and the colour of light at this time of day is rich in reds and oranges. Nevertheless, the auto WB has not rendered the colours satisfactorily. It is biased towards red (what you would expect at this time of day) but it gives no indication that this is a photo taken at sunset. there is no golden glow and areas in shadow appear unnaturally red and the background is decidedly pink!

WB: custom; f 11.0; shutter speed: 1/6 ISO 100

Of the 4 photographs this appears to be the best setting. The colours appear realistic and natural and there is a definite sense that the photo has been taken at sunset. Skin tones are rich and vibrant and the background is rendered accurately.

 

WB: Daylight; f 11.0; shutter speed 1/6; ISO 100

The daylight WB setting has worked well and there is little difference between this and the custom WB setting except that perhaps the colours do not appear as rich  and highlights are perhaps brighter. Again, skin tones are accurate and the background is the right colour.

WB: Shade; f 11.0; shutter speed: 1/4; ISO 100

The Shade setting at this time of day is almost as inadequate as the auto setting. It does not reproduce the colour at the time of day and as with the auto setting the colours are biased towards red under these lighting conditions (interestingly this is not the case in  the other light conditions where Shade WB setting was biased towards orange). Skin tones appear unnatural and unrealistic in the circumstances. The background whilst not pink is till too salmon compared to how it is rendered by the custom and daylight WB settings.

 

In conclusion then this exercise has made it apparent that  the WB setting of a digital camera is crucial to rendering colours accurately and is one of the factors influencing the subtle messages that you want your photo to make (like mood; ambience and emotion). There is no single setting that will work all the time and it is for this reason that I tend to use a custom setting. However, in the absence of a white (or grey) card as a rule of thumb, the auto WB setting should be avoided and you should take into account the lighting conditions at the time of shooting and choose  the appropriate setting, i.e daylight in daylight shooting irrespective of time of day and  shade WB  in shady conditions.