White balance, before or after?

Every digital camera features an essential setting: white balance. This setting neutralizes unwanted color casts and can be adjusted during shooting or in post-production.

White balance is crucial for accurate color reproduction, ensuring colors appear as the human eye perceives them, free from unwanted color casts. The camera’s automatic mode excels in this regard, faithfully rendering the gray concrete of Leitz Park in Wetzlar, Germany, as seen in the Nikon D850 image.

To experiment, set your camera to automatic white balance and observe the results on the camera screen. Under natural light, the displayed colors will typically match the scene seen with the naked eye. However, differences may be more noticeable, and sometimes less tolerable, particularly in photos taken under artificial lighting.

How Human Vision and Cameras Handle White Balance

Unlike cameras, human vision constantly adjusts to neutralize color casts, ensuring that white is always perceived as white, regardless of the light source. This is particularly effective in natural light.
However, in specific environments like a darkroom with red light or under narrow-spectrum lighting such as colored LEDs, objects will appear to take on the hue of the light source.

Currently, cameras cannot replicate the adaptive and neutralizing capabilities of human vision, which are the result of millions of years of evolution. Camera white balance algorithms still have significant advancements to make.

In daylight, the camera’s automatic white balance accurately reproduces colors without any noticeable cast. However, in artificial light, particularly under street lighting at night, the white balance often struggles, resulting in the camera displaying colors that are not perceptible to the human eye. Leica M10-D.

Daylight

Color and motion picture films are balanced for specific color temperatures: 5500 K for daylight or 3200 K for tungsten light. Deviations from these values result in a color cast. Digital cameras, however, provide greater flexibility. For instance, the Nikon D850 offers 16 presets, which include 4 automatic settings, one for tungsten lighting, one for flash, 3 for daylight, 7 variations for fluorescent lighting, and a custom setting.

A Nikon D850’s menu offers a comprehensive range of white balance settings. Although automatic mode often yields good results, manual options like Incandescent, Fluorescent, Sunny, and Flash are crucial for maintaining consistent color temperature across multiple images captured under identical lighting conditions.

White Balance: Automatic vs. Manual Presets

White balance presets are valuable for achieving accurate colors and avoiding unwanted color casts, especially when saving images in JPEG format, where post-production color correction is limited. However, using presets effectively requires photographers to be disciplined and anticipate significant changes in color temperature. While the automatic white balance function often performs well, photographers accustomed to Kodachrome and reversal film might prefer the sunny preset for outdoor photography, which is set at 5500 K.

Setting the white balance outdoors to the “Direct Sunlight” preset simulates shooting conditions with reversal film, like the classic Kodachrome, that was balanced for 5500 K daylight.Leica M10.
The incorrect white balance during the photo capture was due to the Nikon D600 being set to Incandescent mode. This resulted in a blue cast, similar to using 3200K film in daylight. If the image was saved as a JPEG, and not in RAW, correcting the blue tones would compromise the accuracy of other colors.

In the studio, the reference chart

For optimal color fidelity, especially in post-production, it’s essential to save files in Raw format. In the studio, the flash preset matches the color temperature of the flashes, similar to daylight (5500 K). A calibration chart, such as those from Calibrite, X-Rite (ColorChecker), or Datacolor (Spyder Checkr), is valuable for determining a custom white balance during shooting and offers a similar function in post-production. These charts are particularly useful when a subject lacks a neutral value that could otherwise be used to correct color casts.

Accurate white balance, for both shooting presets and post-production, can be achieved in the studio using a chart like the X-Rite ColorChecker or Calibrite ColorChecker.

Postproduction

White balance presets are available in all Raw processing software, though they are often overlooked in favor of custom adjustments using the eyedropper tool. Presets can offer satisfactory results, particularly when the initial balance is unsatisfactory, or when it’s unclear which reference area to use for an eyedropper balance. For instance, in a portrait without a reference chart, selecting the white of the eye to neutralize a color cast may not always be appropriate. If neither the eyedropper nor a preset provides the desired outcome, manual adjustment will be necessary, focusing on the blue-yellow color temperature axis and the magenta-green hue axis.

Image processing programs like Lightroom offer basic camera presets for Raw files. These presets, often bypassed for the eyedropper tool, can produce effective results when standardizing a series of images captured under identical lighting.
The white balance eyedropper tool effectively neutralises undesirable colour casts. When a reference chart is unavailable, locate a neutral grey area within the image. Metal, due to its reflection of ambient light, can serve as a suitable reference for this purpose.

Color fidelity and intentional color cast

Your monitor must be calibrated so that the white balance is accurate and truly matches what you see. In post-production software, start with the preset that is closest to what you want to achieve, then begin by adjusting the temperature slider (the arrow keys on the keyboard change the CT in increments of 50 K). Then move on to the tint to neutralize the magenta or green cast. Finally, remember that white balance is also a personal choice and that a slight cast often adds character to the image.

Manual white balance can be adjusted along two axes: blue-yellow (color temperature) and magenta-green (hue). Although color temperature adjusts in single-unit increments, changes are more perceptible in increments of 10 to 50 K.

Discover the photography courses at Spéos

Spéos offers various training courses ranging from simple one-week photography workshops (initiation and advanced level) to 3-year courses. The long courses to become professional photographers allow you not only to master all the photographic techniques and its vocabulary (blurs, hyperfocus, sharpness zone, depth of field, backlighting, focal length, shutter release, autofocus, wide-angle, rule of thirds, etc.), but also all the stages of shooting and image processing.

Visiting the school allows you to discover the premises, the studios and the equipment, and is undoubtedly the best way to familiarize yourself with your future way of working. This is why, in addition to the open days, Spéos offers throughout the year personalized visits by appointment to come and discover the school with a member of the team.

Text and photos: Philippe Bachelier, teacher of Printing techniques at Spéos