Dive Color: fix blue-green underwater video and photos

Examples

After: coral heads on a reef, colour corrected — Coral heads on the reefA shallow reef full of detail.

Before: coral heads on a reef, straight from the camera — Coral heads on the reefA shallow reef full of detail.

Step-by-step guide

I made Dive Color for my own clips. Everything runs in your browser, so your file never leaves your phone or laptop, and there is no account. This is how I use it, in five steps.

The Dive Color page before you pick a file: the drop area on the left, the sliders on the right. — The page before you pick a file. It works in Safari, Chrome, Edge and Firefox, with nothing to install.

STEP 1 OF 5

Drop your clips

Drag a file onto the picture, or press Choose a file (on a phone it says Pick a dive video or photo). MP4 and MOV videos work, and so do JPG and PNG photos. You can drop several files at once.

The page reads your clip about twice a second to learn how the colour changes as you move. It also guesses the kind of water, and a badge in the Correction card says what it picked, like Looks like green water. You can already see the first frame while it works.

With several files, a list appears under the picture. Each row has a name, a water badge and a status. Click a name to look at that file. If one can't be opened, its row says why and the rest carry on.

GoPro preview files (.LRV, .THM), 360 files, AVI, MKV and RAW photos are not supported. The page tells you if you pick one.

Right after opening a 5 second clip. The strip of small pictures under the video is the timeline, with a trim handle at each end. The status line says Auto-corrected when the reading is done. — A 5 second clip, just after the reading finished. The strip is the timeline.

Four files dropped: three are ready with a water badge, one failed and its row says why. The Export card offers Export all. — Four files: three ready, one failed with the reason in its row.

STEP 2 OF 5

Slide to compare

Left of the line is your original. Right of it is the corrected picture. Drag across the picture to move the line.

Press Play to watch the clip, or click or drag along the strip of small pictures under the video to jump to another moment. The correction follows the colour through the clip.

The line in the middle of the picture, and the playhead at 0:03 on the timeline strip. — The line in the middle, playhead at 0:03.

STEP 3 OF 5 · OPTIONAL

Tweak it

I usually stop at the automatic result. If you want to change it, the picture updates as you move things.

Water sets a starting point for the kind of water: Deep blue, Blue water, Reef, Green water, Shallow and bright or Torch or night. Auto uses the guess from step 1. The guess is plain thresholds on the average colour and brightness of your file, not AI, so change it if it is wrong. Moving a slider doesn't change the Water choice.

Strength mixes the correction with your original. Warmth makes it warmer or cooler. Contrast adds or removes punch.

More controls opens the rest. Saturation turns colour up or down. Red recovery sets how much red gets put back: lower keeps open water blue, higher warms a reef. Tint moves between green and magenta, so slide it right to take the green out of a lake or quarry. Clear the haze adds local contrast for milky water and eases off near black and white. It is plain maths on a blurred copy of the picture. Denoise (Off, Light or Strong) smooths grain in dark footage with a 5 by 5 edge-keeping filter on the original frame, before the colour fix, because the fix would otherwise make the grain stronger. It is plain maths too, and it makes exports slower.

Lock colour uses one setting for the whole clip instead of following your depth. Reset to auto puts everything back.

Pick something white: if sand or a white object still has a cast, press it, then tap that spot in the picture. A ring follows your pointer, and Esc cancels. The tool scales red, green and blue so the spot comes out neutral. It is plain maths, and the change is limited so a bad tap can't wreck the picture. On a video, pick on a typical frame: the same change applies to the whole clip.

Strength 80%, Warmth +15, Contrast +10 and, under More controls, Saturation 130% on the same frame. — Strength 80%, Warmth +15, Contrast +10, and Saturation 130% under More controls.

Picking mode on: a small ring on the sand in the corrected side, and the status line asks you to tap something white. — Picking: the ring sits on the sand.

After the tap the sand is neutral and the status line says White point set. — After the tap the sand is neutral.

STEP 4 OF 5

Pick how to export

For a video, the line under the button tells you the route. Fast export processes every frame at the original frame rate and copies the sound across. Real-time export (slower) means your browser can't encode directly, so the clip plays through once at normal speed while it records.

Bitrate starts on Auto, a bit above your original. Slide it up for more detail and a bigger file. For a photo you get Save PNG and Save JPG at full size.

Keep only part of a clip: drag the two handles on the strip under the video, or move the playhead to where it should begin and press Set start, then do the same with Set end. The dimmed parts are left out. With a handle selected, the arrow keys nudge it by a tenth of a second (Shift: one second). Clear puts the whole clip back. Only the kept part is exported.

Show has two choices. Corrected is the normal export. Before and after puts the line into the video or photo where you left it, with small Before and After labels. The file name ends in -beforeafter.

Several files: the card says Export all, and it unlocks when every file has been read. Each file keeps its own correction, trim, white point, water type, Show choice and line position. The sliders and bitrate apply to all of them. Photos in the list are saved as JPG.

The Export card for an 8 second clip: auto bitrate, the Show choice set to Before and after, and the fast export line. — The Export card for an 8 second clip, with Before and after chosen.

STEP 5 OF 5

Wait, then save

A progress bar and a pill on the picture show how far along it is, with a rough time left. Cancel stops it any time. Keep the tab open until it finishes, and in front if the page is on the real-time route. The browser warns you if you try to leave.

When it says Done, the file downloads, named like your original with -divecolor added. On a phone, tap Save to Photos / share and choose Save Video. There is a plain Download button too.

Export all does one file at a time, and the bar says which, like File 2 of 3. A file that fails doesn't stop the rest. In Chrome and Edge the page asks for a folder once and writes each file straight into it. Other computers download each file as it finishes. On a phone the queue stops after each file and says Save this one to continue.

Export just started. The bar sits at 0% and fills as frames are done. — Export just started, the bar at 0%.

The finished message on a computer. The phone buttons only appear on touch screens, so they aren't in this picture. — The finished message on a computer. The phone buttons only show on touch screens.

After Export all: three rows say done, the failed one still shows its reason, and the line under Export all counts them. — After Export all: three done, the failed one still shows why.

When it looks wrong

Too strong or too red: Lower Strength to 60 to 80%.
Too cold or too warm: Move Warmth.
Flat or milky: Raise Contrast. For real haze, open More controls and raise Clear the haze.
Grainy night dive: Open More controls and choose Denoise: Light. Torch or night in Water already does this.
Colours too strong or too dull: Open More controls and change Saturation.
Open water looks purple: Choose Deep blue in Water. Still purple? Lower Red recovery in More controls.
Reef still looks blue: Choose Reef in Water.
The Water badge guessed wrong: Pick the right one: Deep blue for open water and big animals, Blue water for open sea, Reef for a colourful reef up close, Green water for lakes, fjords and quarries, Shallow and bright for sunlit reefs and sand, Torch or night for dark dives lit by your light.
Green water: Open More controls and slide Tint right, towards magenta.
Sand looks pink: Press Pick something white and tap the sand.
The colour shifts with depth and you don't want that: Turn on Lock colour.
Very deep or dark shots barely change: Little red is left to rebuild at depth, so expect less from them.
Export is slow or stops: Keep the tab open and in front. A long 4K clip is slow on a phone, so trim it first with Set start and Set end.
Sharing the before and after: Move the line where you want it, set Show to Before and after, and export. The line and labels are in the file, so it works anywhere you post it.
A whole dive's clips: Drop them all together, check the sliders on the first one, and press Export all.
The file won't open: Check it is MP4, MOV, JPG or PNG. On iPhone, use Safari.

How it works

Step-by-step guide with screenshots

Why dive footage goes blue-green. Water soaks up red light first, then orange and yellow. A few metres down almost no red reaches the camera, so everything turns blue-green, and the camera's white balance can't bring back colour that never arrived.

For every picture, the tool does three things:

Rebuilds the red. Green light survives much deeper than red. So the tool adds red back to each pixel based on how much green it has, more where the red is weakest, and never takes any away. This is the red-compensation step from Ancuti et al., 2018.
Balances the colours. It assumes the scene should average out to neutral grey (the "gray world" idea) and scales red, green and blue until they do.
Clears the haze. The darkest 0.5% of the picture becomes black and the brightest 0.5% becomes white, which stretches out the flat, milky look.

No flicker on video. The colour isn't re-measured every frame. The tool reads your clip about twice a second, then smooths those readings, so the colour follows you as you change depth without pulsing.

Where it runs. All of this happens on your own device, in this browser tab, on your graphics chip. Your file is never uploaded: there is no server and no account, and once the page has loaded it even works with Wi-Fi off. Strength, Warmth and Contrast let you dial it back or push it further. Under More controls, Saturation blends each pixel towards its own grey, or away from it, and Red recovery turns the red rebuilding in step 1 down or up. Tint shifts the picture between green and magenta, for green water. Clear the haze adds local contrast: it compares each spot with a blurred copy of the corrected picture and pushes it further from that, easing off near black and white. Pick something white scales red, green and blue so the spot you tap comes out neutral. Water sets those sliders to a starting point for the kind of water you dive in. Auto guesses the kind from the average colour and brightness of your file, with plain thresholds, not AI.

Limits

Speed depends on your device, so long 4K clips take a while, especially on phones. On a phone the finished video is held in memory until you save it, so very long 4K clips may be too much: trim them first (Set start / Set end sit under the video). Video exports as MP4 at the original frame rate and, where the browser can encode it, the original size (5.3K GoPro footage comes out at 4K-class size). iPhone HDR (Dolby Vision) clips come out in standard range. Very dark or very deep shots have little red left to rebuild, so expect less from them.

Dive Color