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?
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.