What is Mired Shift in white balance?

Mired stands for Micro Reciprocal Degrees (Mired = 1,000,000 / Kelvin). While Kelvin changes non-linearly to human vision, Mired shifts are perceptually uniform. The Mired shift formula is: Mired Shift = (1,000,000 / Target Kelvin) - (1,000,000 / Source Kelvin). A positive value indicates warming filtration (e.g. 85B), while negative indicates cooling (e.g. 80A).

How do I use an 18% Gray Card to set custom White Balance?

Place an 18% neutral gray card in the same light hitting your subject. In our tool, click on the gray card surface with the eyedropper probe. The engine analyzes the RGB disparity and computes chromatic gain multipliers (G_R, G_G, G_B) that neutralize unwanted color casts.

What is the difference between Color Temperature (Kelvin) and Tint?

Color Temperature governs the blue-amber axis (warm vs cool light along the Planckian black-body locus). Tint governs the orthogonal green-magenta axis (Duv offset), essential for balancing artificial lights like industrial fluorescents or LED panels that exhibit heavy green spikes.

What are standard camera white balance presets?

Standard camera presets include: Tungsten (3,200K), Fluorescent (4,000K), Daylight (5,600K), Flash (5,500K), Cloudy (6,500K), and Open Shade (7,500K).

White Balance Calculator, Kelvin & Gray Card

White Balance Parameters

Tungsten → Daylight

Camera WB Presets Quick Kelvin calibration

Source Kelvin 312 Mireds

Target Kelvin 179 Mireds

Source Scene Color Temperature 3,200 K (Tungsten Incandescent)

1,800K Candle 3,200K Tungsten 5,600K Daylight 7,500K Shade 10,000K Sky

Tint Balance (Green – Magenta Axis) 0 (Neutral ±0.0 Duv)

-40 Green Tint 0 Neutral +40 Magenta Tint

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Upload image with gray card or neutral surface

Instant Preset Scenes Test color casts & gray card

Source Temperature

3,200 K

312.5 Mireds • Tungsten Incandescent

Target White Point

5,600 K

178.6 Mireds • Direct Noon Daylight

Mired Shift & Filter

-134 Mireds

Requires 80A Cooling Filter (Blue)

Tint & Duv Offset

0 Tint

Neutral • Balanced on Planckian Curve

18% Gray Sample Patch

RGB 180, 140, 95

Gain Multipliers: R:0.75 | G:0.96 | B:1.42

Detected Color Cast

Warm Amber Cast

+42 Blue gain needed to neutralize

Interactive Gray Card Eyedropper & Correction Viewport

Click gray card to sample

💡 Click on the 18% gray card or any neutral gray/white surface to auto-calibrate white balance

Sample: RGB(180, 140, 95)

Complete 10-Tool White Balance & Kelvin Calibration Matrix

10 Tools Evaluated

Tool Name	Calculated Value / Metric	Category	Standard & Technical Detail

Complete Photographer's Guide to White Balance, Kelvin & Gray Cards

White balance is the calibration of color values in an image to ensure neutral objects (such as pure whites, grays, and black textures) appear truly neutral without unnatural warm amber, cold blue, or fluorescent green casts.

1. The Mired Shift Formula & Optical Warming/Cooling Filters

In analog photography and cinematography, physical glass filters on camera lenses or gel sheets over strobe lights shift color temperature. Because Kelvin scales non-linearly to human vision, the photographic industry uses Mireds (Micro Reciprocal Degrees):

Mired Value (M) = 1,000,000 / Kelvin (K)
Mired Shift (ΔM) = (1,000,000 / Target Kelvin) − (1,000,000 / Source Kelvin)
Example: Shooting Tungsten (3,200K = 312.5 Mireds) to Daylight (5,600K = 178.6 Mireds)
ΔM = 178.6 − 312.5 = −133.9 Mireds → Requires Kodak 80A Cooling Blue Filter

A positive Mired shift requires amber warming filtration (e.g. 81A, 85B), whereas a negative Mired shift requires blue cooling filtration (e.g. 82A, 80A).

2. How an 18% Gray Card Calibrates Digital RAW Files

Human eyes adapt dynamically to ambient light through chromatic adaptation (a white sheet of paper looks white under indoor incandescent bulbs and outdoor noon sun). Digital camera sensors, however, record raw spectral radiance without adaptation. Sampling an 18% neutral gray card computes exact gain multipliers:

Sampled Patch = (R_sample, G_sample, B_sample)
Luminance Reference Y = 0.2126·R + 0.7152·G + 0.0722·B
Chromatic Adaptation Gains: G_R = Y / R_sample, G_G = Y / G_sample, G_B = Y / B_sample
Corrected Pixel: R_new = min(255, R × G_R), G_new = min(255, G × G_G), B_new = min(255, B × G_B)

3. The Tint Axis: Green vs. Magenta (Δuv)

While Kelvin governs the correlated black-body curve from warm amber to cool blue, many modern light sources—such as cheap LED panels, street sodium vapor, and office fluorescent tubes—radiate off the Planckian locus. Fluorescent tubes emit high mercury vapor peaks resulting in an obnoxious green spike. A positive Tint value adds Magenta compensation to neutralize green casts.

4. Kelvin to Photographic Lighting Reference

1,800K – 2,000K (Candlelight / Match Flame): Deep warm amber glow, heavy red radiation.

2,800K – 3,200K (Domestic Tungsten / Halogen): Standard indoor incandescent bulbs; warm household feel.

4,000K – 4,200K (Cool White Fluorescent): Commercial offices; often requires +15 to +30 Magenta tint correction.

5,500K – 5,600K (Photographic Strobe / Direct Noon Daylight): Clean neutral white baseline for commercial, portrait, and product photography.

6,500K (Cloudy / Overcast Sky): Diffuse cool light; requires slight warming to prevent pale skin tones.

7,500K – 8,500K (Open Daytime Shade): Deep blue sky reflection without direct sun; cool blue shadows.

10,000K+ (Clear Blue Sky in High Mountains): Intense blue radiation; requires heavy warming filter (+150 Mireds).

Frequently Asked Questions

Yes! RAW files store unbaked sensor data. The camera white balance setting is simply metadata attached to the file. You can change Kelvin and Tint in post-production with zero image degradation. However, JPEG files have white balance baked into their 8-bit pixels; adjusting JPEG white balance can cause banding and color noise.

Most white copy paper contains Optical Brightening Agents (OBAs) that fluoresce in ultraviolet light, introducing an unwanted violet/blue spike. Professional 18% gray cards are spectrophotometrically neutral across the entire visible spectrum (400nm to 700nm) and reflect exactly 18% of light without specular glare.

Color Compensating (CC) filters—such as CC30M (30 Magenta) or CC15G (15 Green)—adjust the orthogonal green-magenta axis. When shooting under fluorescent lights, placing a CC30M filter on your lens or adding a "Minus Green" gel over your flash balances the light spectrum before it hits your sensor.

If your camera is set to Tungsten (3,200K) while shooting outdoors in daylight (5,600K), your photos will have an extreme, unnatural blue cast. Conversely, if set to Shade (7,500K) indoors under incandescent lights, your image will turn intensely orange and yellow.