Color Temperature, White Balance, and Exposure – Quick Reference

White balance defines how a camera renders white under different lighting; a white object reflects the color of the illuminating light.
- Outdoors: light can skew blue; indoors: orange/tungsten; fluorescents: green.
Color balance changes with lighting conditions; Kelvin is used to measure these shifts and guide adjustments.
Kelvin introduces a common framework for comparing light sources and planning color correction.

Common reference values (approx.):
- $3200\,\mathrm{K}$ = tungsten
- $5600\,\mathrm{K}$ = daylight
- Candlelight: $1700-1900\,\mathrm{K}$
- Sunrise: $2000\,\mathrm{K}$
- Magic hour: ~ $2500\,\mathrm{K}$
- Noon / bright daylight: $5600\,\mathrm{K}$
- Fluorescent lights: ~ $5000\,\mathrm{K}$
- Daylight with sky tint (blue sky): up to ~ $9000\,\mathrm{K}$
- Very blue skylight: ~ $28000\,\mathrm{K}$
Lower Kelvin (warmer) vs higher Kelvin (cooler) — warmer light flatters skin; cooler light shifts toward blue.
Tungsten light is warm; daylight is cooler; fluorescent can have a greenish tint.
Some light values vary by location and moment (e.g., sunrise vs noon), so testing on set is important.
Skin and color performance:
- Skin tones are most flattering under warmer light; skin reflects best around 600–700 nm (orange range).
- Fluorescent light can push a greener tint; correction often involves magenta/green adjustments.
Practical science notes:
- Kelvin scale is tied to black-body radiation: as an object heats from near zero to higher temps, it glows from red to white to blue.
- Kelvin scales are used in various fields (photography, astronomy).

Approaches: Auto White Balance, presets, and manual white balance.
- Best practice: use a mix; avoid relying solely on auto WB mid-shot.
- Use white balance cards for precise manual readings when possible.
- If moving between locations, set and remember multiple WB presets.
On-set tips:
- Test WB before and during shoots; adjust as lighting changes.
- Calibrate WB to maintain consistency across shots; post correction is possible but harder to perfect.

ISO is sensor sensitivity to light; higher ISO = more sensitivity, enabling shooting in darker conditions but with more noise.
Typical camera ranges: $100\text{ to }6400$ (and higher on some models).
Native ISO (Canon C500 example): $800$ .
Exposure triangle: relationship between aperture (f-stop), shutter speed, and ISO to achieve proper exposure.
- Aperture (f-stop) controls how much light enters: larger aperture (lower f-number) = more light.
- Shutter speed controls how long light hits the sensor; slower speeds = more motion blur.
- ISO controls sensor sensitivity; increasing ISO allows shooting in darker light but increases noise.
Stops and doubling:
- Each stop change doubles/halves the amount of light or sensor sensitivity.
- Formula intuition: $\text{Exposure change} = 2^{\Delta\text{stops}}$
Latitude:
- Modern cameras offer substantial latitude (often ~16 stops) for dynamic range, vs film’s latitude historically being different.
Why this matters: higher native latitude lets you push/pull exposure in post, but dynamic range has practical limits.

IRE (Institute of Radio Engineers) scale: 0 to 100; used for brightness/contrast assessment on cameras.
- 0 = crushed blacks; 100 = clipped whites.
False color: overlays mapped to IRE values to gauge exposure without guessing.
- Common mapping (on many cameras):
- Red = clipping whites
- Yellow/ Pink = highlights (skin tone ranges)
- Green = midtones / skin tones
- Blue = shadows / detail in shadows
- Purple = very dark areas with little detail
Zebras: overlays set to a percentage (often around 60–65%) to indicate when skin tones are properly exposed or when highlights are blown.
- Example: set zebras to 65% to monitor facial skin exposure; use as a quick dynamic check.
Practical use:
- False color helps create contrast and avoid flat midtones.
- Zebras and false color can guide lighting decisions on a documentary shoot or interview setup.
- Reading IRE alongside the actual image helps judge texture and detail in shadows/highlights.

0: pure black
1–2: near black with minimal tonality
3: dark shadows with some texture
4: dark foliage / dark materials
5: middle gray / average tones
6: average skin or stone in daylight
7: light with texture (skin highlights, light edges)
8: light with texture (snow/stone with texture)
9: highlight with texture (slightly blown highlights but still texture)
10: pure white highlights
Use as a conceptual guide for desired texture and contrast; aim for a range that preserves texture in shadows and highlights rather than crushing all detail to middle gray.

Dynamic lighting creates more engaging images than midtones-only lighting.
Depth and contrast: place subjects with background elements (windows, landscapes) to add depth and visual interest.
False color is a useful tool for determining how light interacts with skin and surfaces and for guiding lighting adjustments.
On documentary or interview setups, think about where the light is coming from and how it interacts with the subject and background.
When choosing locations, consider background texture and contrast to avoid boring shots (e.g., plain drywall walls).

Common WB targets:
- Tungsten: $3200\,\mathrm{K}$
- Daylight: $5600\,\mathrm{K}$
- Candlelight: $\approx 1700-1900\,\mathrm{K}$
- Sunrise: $\approx 2000\,\mathrm{K}$
- Magic hour: $\approx 2500\,\mathrm{K}$
- Fluorescent: $\approx 5000\,\mathrm{K}$
- Daylight blue variants: up to $\approx 28000\,\mathrm{K}$
Skin tone guidance: warm light around 600–700 nm yields healthier skin tones.
Common lighting tools on set:
- Auto WB, presets, manual WB (prefer manual with card measurements for accuracy)
- False color, zebras, and IRE waveform to monitor exposure and contrast
Key concepts to remember:
- Exposure is a balance of aperture, shutter, and ISO; adjust for the look you want, not just to avoid clipping.
- Higher latitude allows more flexibility in post, but plan lighting to achieve the desired look in-camera.