How to brighten a video on a Mac

iMovie gives you more direct control than the single Light slider, and it suits clips that are already part of a project. The Mac version’s colour tools sit in the row of buttons above the viewer.

1. Select one or more clips in the browser or the timeline.
2. Click the Color Correction button above the viewer.
3. In the multislider, drag the grey handle in the middle to the right to brighten the clip.
4. Drag the black handle to lift the shadows, the white handle to set the highlights, and either half-moon handle to change contrast.
5. If the colour looks thin afterwards, drag Saturation up a little; Color Temperature corrects an orange or blue cast.
6. To export, choose File → Share → File, set Format, Resolution, Quality and Compress, click Next, name the file and click Save.

For a one-click fix, the Enhance button improves a clip’s picture and sound together, and Color Balance → Auto removes colour casts and maximises contrast. Neither is aimed at dark footage specifically, so check the result against the manual controls. Reset next to the colour balance controls removes the automatic change.

QuickTime Player is a viewer with a few editing commands. Apple’s guide lists trim, split into clips, rearrange clips, add a clip, rotate or flip, and remove the audio or video track. There is no brightness, exposure or colour control, so it can’t produce a brighter copy.

What it can do is export. File → Export As offers 4K, 1080p, 720p and 480p, with sizes larger than your movie dimmed. Exports are QuickTime movies (.mov); QuickTime Player doesn’t export MP4. Raising your Mac’s display brightness makes playback look lighter on your screen but changes nothing in the file.

If you only need a brighter picture while watching, VLC for Mac has Image Adjust sliders under Window → Video Effects...; see how to brighten a video in VLC.

These sliders sound alike but move different parts of the picture. Knowing which is which saves a lot of back and forth.

• Exposure scales the whole image, much like a longer shutter or wider aperture would have. Every tone rises, so bright areas reach pure white first.
• Brightness in Photos and the grey handle in iMovie also raise the overall level. Apple doesn’t publish how they differ from Exposure, so try both: if Exposure blows out a bright area, Brightness may lift the scene with less clipping.
• Shadows in Photos and the black handle in iMovie target the darkest areas. This is the one to use when a face is lost in shade but the background is fine.
• Black Point sets where the image becomes completely black. Pulling it down after brightening restores some depth.
• Brilliance in Photos brightens dark areas and adds richness without adding colour saturation.

A dark clip with a bright window behind the subject needs shadows lifted and highlights held back, not more exposure; brightening a backlit video goes into that case.

• Grain appears because low light leaves random noise in the dark parts of each frame, and brightening lifts the noise along with the picture. Stop as soon as the subject is clear rather than pushing the slider to the end.
• If the clip looks grey and flat, the darkest tones have been lifted too far. Lower Black Point in Photos or move the black handle back in iMovie.
• If skin looks orange or green, correct the colour after the brightness: Color Temperature in iMovie or the Color adjustment in Photos.
• If the clip came from an iPhone, check the exported copy on the screen you will watch it on; brightening iPhone videos covers the phone side.

Every export from Photos or iMovie writes a new compressed file. Choose the same resolution as the source so you don’t add softness on top of the grain.

brighten.video works in a modern browser on your Mac. The clip is processed on your Mac and never uploaded, and there is no account or watermark.

• Click Select video, then press Auto brighten or choose Night video, Dim room, Backlit or Slightly dark and set Strength.
• Drag the Before and after divider to compare. More options adds Exposure, Midtones (gamma), Shadows, Highlights, Blacks, Whites, Noise reduction and a Histogram or Waveform readout.
• Click Export video, set Format, Size and Quality in Export settings, and keep Keep sound on for the audio. Then click Download video.

It always re-encodes the video, and no tool can recover detail that was recorded as pure black. What it offers is a draggable before and after split, and an Auto brighten that keeps very dark clips looking like night rather than daylight.