Gamma Explained: Why Your Shadows Look Wrong

Gamma describes the curve that maps input signal to displayed brightness. Get it wrong and images look washed out or crushed.

The standard

Most content is mastered for gamma 2.2 (sRGB). That's your target for general use.

The number is an exponent. A signal at 50% doesn't come out at 50% brightness — raised to the power of 2.2, it lands closer to 22%. That's deliberate: human vision is far more sensitive to changes in dark tones than bright ones, so the encoding spends more of its available steps down in the shadows where you can actually see them.

A few places use different targets. Movies mastered for a dark viewing room often follow a curve closer to 2.4, which deepens shadows in a blacked-out room but crushes them in daylight. Apple's Macs defaulted to 1.8 for years before switching to the 2.2 standard, which is why very old Mac-made images sometimes look dark on modern screens. Unless you have a specific reason otherwise, 2.2 is the right answer.

What bad gamma looks like

• Too low (e.g. 1.8): images look flat, washed out, gray blacks.
• Too high (e.g. 2.6): shadows crush to black, picture looks contrasty and "muddy" in dark scenes.
• Uneven: fine in the midtones but wrong at one end — usually a sign of an aggressive picture mode or a bad calibration profile rather than the panel itself.

The everyday symptom is that dark scenes in films and games are unreadable, or that photos you edit look completely different on someone else's screen.

How to check it

Run the Gamma Test and find the patch that blends into the surrounding stripes — that number is your gamma. Cross-check with the Greyscale Test: with correct gamma, the step from black to white looks evenly spaced — no big jump near the dark end and no detail vanishing into black. The mid-gray step should read as a believable middle, not near-white or near-black.

Three things make this reading much more reliable:

1. Sit centered and square to the screen. Gamma shifts with viewing angle, badly on TN panels and noticeably on VA. Check with the Viewing Angle Test — if the pattern changes as you lean, you have to judge gamma from dead center.
2. Step back. The gamma patch is a dithered pattern; up close you see the dither instead of the average tone.
3. Use normal room lighting. A screen judged in a dark room will end up set too bright for daytime use.

Also run the Black Level Test and the Contrast Test afterwards. Gamma set too high hides the darkest steps entirely; too low and the near-black steps separate but the whole image looks hazy.

What throws gamma off

• A picture preset. Modes named Vivid, Dynamic, Movie, Game, sRGB or Cinema each apply their own curve. Some also enable dynamic contrast, which changes gamma continuously as the image changes — turn that off before measuring anything.
• An ICC profile. A profile left behind by a previous calibration, or one downloaded for a different unit of the same model, loads a gamma correction into the GPU at login.
• GPU control panel settings. Nvidia, AMD and Intel each expose their own gamma or digital vibrance sliders that stack on top of the monitor's own.
• Night mode / blue light filters. These shift white point and often gamma with it.
• HDR mode. HDR uses an entirely different transfer curve. If HDR is on but you're viewing normal content, everything will look wrong and no gamma setting fixes it — switch HDR off for SDR viewing.

How to fix it

• Set your monitor's gamma preset to 2.2 if it has one. This is the best place to correct it, because it happens in the display rather than by throwing away signal levels in the GPU.
• On Windows, open Color Management, check the Advanced tab for a stale profile, then use the built-in display calibration wizard, which adjusts gamma by eye with a small hidden-dot pattern.
• On macOS, use the Display Calibrator Assistant, opened from the color-profile options in the Displays settings (holding Option as you launch it reveals the expert version with finer gamma controls).

Correct in the monitor first and in software second. Heavy software correction compresses the number of distinct levels being sent to the panel, which can introduce visible steps in gradients — check for that afterwards with the Color Gradient test and see what is color banding if you spot it.

For reference work, a colorimeter measures gamma precisely — but the greyscale pattern gets most people close. If you're setting up without one, the full by-eye routine is in how to calibrate your monitor without a colorimeter, and photo editors should also read monitor setup for photo editing before trusting what they see.