Posts on The Image Plane occasionally deal with subjects other than photography. The entire contents to date are listed to the right. Non-photographic subjects include: dementia, space exploration, and the Border Terrier.
The specific links below will take you to pages that may be of interest to photographers:
If you’re a new amateur digital photographer you may have been wondering about White Balance. What is it? What can it actually do for you?
Put very simply, white balance is an electronic process that defines how a camera represents colour in a digital image. The system will respond uniquely to the colour temperature of different light sources—warm to cool, red to blue. Think of the difference between a cloudless sky at dawn and at noon. A camera can be set to assess colour temperature automatically (auto white balance), or the photographer can make precise manual adjustments to suit the light and the subject. In this strict context we should note that a regularly calibrated monitor is essential to further evaluate images for exact colour editing.
We should also remember at the outset that auto white balance is in fact very effective in most situations. So we should ask ourselves how useful white balance control will actually be in practice. Will it play a significant role in more typical day-to-day shooting? Well, to be honest, probably not.
Shoot a snow scene under an overcast dawn sky (see bottom of page) and you’ll find that auto white balance will typically respond differently as the camera is moved, or as the masked, rising sun influences the light’s hue. But no image can be said to be clearly ‘wrong’. Some images may look a little blue; others may have the slightest hint of red or pink. Of course both can be altered in software to suit personal preferences or just to get a totally neutral result. What are we actually looking for and why? What do we actually notice? We expect midday clouds to be more neutral and typical Caucasian skin tones not to be too cool or too warm, but beyond such contexts there is scope for personal expression.
Very often it’s simply impossible to say what is right or best—it’s in the eye of the beholder, a personal preference. A lot depends on how critical the work is. Essential, finely tuned colour balance isn’t common and rarely necessary. How critical does the dedicated amateur need to be to get strong images and prints? Well, it depends…
It depends how critical colour is to the image you’re about to create. It depends if you need to shoot indoors away from natural light and without flash. It depends on whether or not you’re shooting several linked shots when it’s usually best if the colour balance is fixed rather than automatic. For example, you may want to stitch individual shots together to create a panoramic image and you won’t want to use the camera’s auto white balance calculations because they may well create slightly different colour casts and tones for each shot. Setting the colour balance may be useful in a particular situation where the position of the camera and a lens’s focal length are constantly changing.
If the prevailing light source results in an extreme auto-generated cast, manually selecting the most appropriate white balance will produce a consistent result and so avoid demanding corrective work later in software. Locking in the colour balance with a manual white balance setting will be helpful too if you have to shoot a variety of subjects under exactly the same light. Adjusting white balance in-camera can enrich colour tones in an image in a way you wouldn’t get with automatic calculations, so experimentation can be rewarding.
White balance can be adjusted in RAW-editing software.
Of course, if you’re shooing RAW files you can adjust the white balance shot settings later in software (see above). It makes sense to adjust colour balance before using other tools like curves—tonal adjustments affect the appearance of colour. In tricky situations more typical of professional product photography, where colour tones are very important, it’s often more efficient to make the best possible adjustments in-camera. This approach simplifies the workflow.
Auto white balance is often a better option when shooting JPEGs due to powerful in-camera white balance processing that works on the colour tones before the image is saved to the card. This may explain the RAW+JPEG unedited images below. The JPEG’s red channel has been much better aligned with the mid- to darker tones in the image to produce a more neutral, acceptable result. However, take a look at the slight red shift in the JPEG’s brighter tones to the right. This marginal difference will subtly affect the colour tone of the snow. But both files can be tonally adjusted to taste.
It’s also possible to create a custom white balance reading that enhances or best suits the light in the scene, or the specific light source that’s falling on the main subject. To do this you set the camera to neutralise colour balance by reading a white card that is placed in the same light source.
It’s fun to creatively experiment with white balance. But it’s likely that busy professionals operating in strict environments to industry standards will find white balance much more useful than the average amateur.
Camera: Fujifilm X10. Aperture priority, ISO 200, 1/400, F2.5.
Over the summer I was involved with an ambitious landscaping project. Well, it was certainly ambitious for just two people. When it was finished, and we were feeling weary but very pleased with ourselves, on a July evening I wandered around taking shots of whatever caught my eye.
A hanging basket of petunias was lit by the late evening sun. I put the lens almost into the flower and managed just one hand-held shot. What makes this image for me is the soft light that’s shining through the flower rather than on it.
Why ISO 200? I forgot to check.
