Problems with White Balance ...

Joined: August 28th, 2018, 8:39 pm

August 29th, 2018, 4:48 pm #1

I have a Konica Minolta 'Dimage Z10', and am trying to calibrate the 'White Balance' for 
indoor work. The instructions suggest that the camera should be focused on a sheet of 
white paper (with the whole area in the frame), and with Aperture Priority selected (and no flash), 
the 'Custom Set' be used to register the 'white' value of the paper. I then photograph my subject 
(a single model or a diorama) against a similar white background. Although the result is successful 
in taking away the yellow cast from the artificial light, when the images are viewed on my computer, 
the background invariably appears grey. Am I missing something important?
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Joined: August 19th, 2001, 6:41 pm

August 29th, 2018, 8:44 pm #2

White balance is normally calibrated using either white paper or a grey card. Now the process is normally as you describe and it does remove the colour cast from your final image. The background may look grey as the subject diorama or model is correctly exposed the background will not be. You can try to apply exposure compensation to lighten your image especially if you are using a smaller f-stop. I always shoot RAW image files as I have a much larger latitude for any exposure corrections than I would if I shoot jpg - but that’s me not you.
The alternative is to check the ‘value’ assigned by your calibration shot and then manually input the value - measured in Kelvin. Another point to remember is that the white paper should be in the same position as your model. An alternative colour for the background is blue.

I hope this helps.
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Joined: August 19th, 2001, 6:41 pm

August 29th, 2018, 10:29 pm #3

Cromwell Final (10).JPG This is the Airfix Cromwell - shot on a white background.
Final (1).jpg
...and the Dragon/Orange Box M1A1
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Joined: August 28th, 2018, 8:39 pm

August 30th, 2018, 11:00 am #4

On reflection, looking back at my own photos, the grey backgrounds provide a more natural tone, 
rather than the stark appearance of white. The two images you have shown here confirm this thought.   
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Joined: August 19th, 2001, 6:41 pm

August 30th, 2018, 7:26 pm #5

These images were for Airfix Model World, I recall having to reshoot them to get the background whiter. The magazine specifies white for completed and blue for in progress shots.
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Joined: August 28th, 2018, 8:39 pm

August 30th, 2018, 9:31 pm #6

Many of my dioramas have appeared in Military Modelcraft International over the years. Fortunately, they have been able to remove the grey from the backgrounds without any problem, but I have often struggled to get a satisfactory white myself. The problem with adjusting the 'exposure compensation' setting on the camera is that this (presumably) affects the tonal values in the subject, as would any adjustments on the computer.   
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