Light Leaks: The Warm Streaks Film Cameras Made by Accident
Light entered through a gap in the camera back, so a real leak always starts at an edge and fades inward. That single rule is what separates a convincing leak from an orange blob floating in the middle of the frame.
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Leaking edge
Light entered the camera through a gap, so it always comes from an edge rather than floating in the middle.
Colour
Warm. Real leaks run warm because film is most sensitive to red at its edges.
Streaking breaks the leak up the way a real one is. It uses a fixed seed, so the same photo always gets the same leak.
Presets
Your photos are never uploaded. The leak is composited and exported inside this browser tab.
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Everything this tool does
Always starts at an edge
Light got in through a gap in the camera body, so the leak is anchored to a side and fades inward. A glow that starts in the middle of the frame is not something a camera can produce.
Falloff that never rises again
Sampling across the frame from the leaking edge, the leak's contribution decreases at every single step. Overlay-based tools break this, because a stock leak image is bright wherever it happens to be bright.
Screen blending
A leak is extra light, so it can only brighten. A strong leak over a pure white frame leaves every pixel at 255 rather than clipping, and shadows lift toward the colour instead of being replaced by it.
Streaking that breaks it up
Light through an irregular gap is uneven, not airbrushed. Smooth interpolated noise along the leak gives that, without dropping to per-pixel randomness which would read as grain.
Five colour ramps
Warm, red, gold, magenta and rainbow, each a real gradient rather than a flat tint, because a leak changes colour as it travels inward.
Deterministic
The streaking uses a fixed seed, so the same photo and settings always give the same leak and a whole batch gets a consistent treatment.
Drag to compare
Before and after share one frame with a slider, which is how you judge whether the leak has gone too far across the picture.
Six purpose-built presets
Classic warm, subtle, heavy fogging, narrow streak, dreamy magenta and one with no streaking for comparison.
Batch with one ZIP
Apply the same leak across a set and take everything as a single archive built in your browser.
Nothing is uploaded
No server, no queue, nothing to delete afterwards. Close the tab and every trace of the image goes with it.
What each control does
The edge and the position say where light got in; reach and width say how much of the frame it covered. Streaking is what stops it looking airbrushed, and it matters more than its size suggests.
| Setting | What it does | Try | Good for |
|---|---|---|---|
| Reach 20-40 | just catches the edge | intensity 50-70 | Subtle, believable |
| Reach 60-100 | crosses most of the frame | intensity 60-80 | Dramatic, obvious |
| Width 15-35 | a narrow streak | streak 40-70 | Slit in the camera back |
| Width 60-100 | a broad wash | streak 20-40 | Whole edge fogged |
| Streaking 0 | a clean airbrushed band | rarely | Graphic, not film |
| Streaking 40-70 | broken up, organic | any | The realistic range |
| Warm or gold | what real leaks look like | any | Believable results |
4
edges
5
colour ramps
0
files uploaded
Screen
blend, only adds light
ZIP
batch download
Free
no account needed
FlipMyFormat vs other light leak tools
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Leaks start at an edge, as real ones do | ||
| Brightness falls off monotonically inward | ||
| Screen blending, so light is only added | ||
| Deterministic streaking, so a batch matches | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How to add a light leak that looks like an accident
Light leaks were a fault. A camera back that no longer closed properly, a foam seal that had perished, a roll of film loaded in bright sun, and stray light struck the emulsion before the picture was taken. Everything people find appealing about the look follows from that physical fact, and getting it right is mostly about respecting it. The single most important rule is that the light got in at an edge. It came through a gap in the body, so it struck the film hardest nearest that gap and fell away as it spread inward. A leak that starts in the middle of the frame is not something a camera could produce, and although people cannot always say why, it reads as fake immediately. So choose an edge, choose where along it, and let it fade inward. The second rule is that leaks are messy. Light coming through an irregular gap and bouncing around inside a camera body does not produce a clean airbrushed gradient; it produces something broken up, uneven, and different every frame. That is what the streaking control is for, and a leak with none of it looks like a graphic overlay rather than an accident. Third, keep it warm. Colour film is more sensitive to red at its edges and stray light usually arrives through amber-ish plastic, which is why almost every real leak sits somewhere between gold and deep red. And finally, restraint: one leak, from one edge, is a photograph with a light leak. Four leaks from four edges is a photograph with a filter on it.
- 1
Add your photos
Drag them in, click to browse, or paste with Ctrl+V. Leaks sit best on photos that already have a warm or nostalgic feel.
- 2
Pick an edge and a position
Light got in through a gap, so choose which side and where along it. Keeping it to one edge is what makes it believable.
- 3
Set reach, streaking, then export
Reach decides how far across the frame it travels. Add streaking so it does not look airbrushed, then save individually or as one ZIP.
Why edge and falloff matter more than colour
Light entered at one place and spread
The physics is simple and it constrains the result completely. Light struck the film through a gap, so its intensity was greatest at the point of entry and diminished with distance as it spread and scattered. Reproducing that means the leak has to be anchored to an edge and has to weaken monotonically as it travels inward, with no bright patches further in than the point it came from. We verify exactly that: sampling across the frame from the leaking edge, the leak's contribution decreases at every step, never rising again anywhere along its path. That property is what your eye uses to decide whether light entered the camera or was pasted on afterwards, and it is the one most overlay-based tools get wrong, because a stock leak image dropped on top has bright areas wherever the original photograph happened to have them.
Light adds, it never subtracts
A leak is light arriving at the film in addition to the light forming the image, so it can only ever make an area brighter. That is reproduced with screen blending, which inverts both values, multiplies and inverts back, and has the useful property that it can never darken a pixel and never pushes one out of range. Two consequences follow that you can check. An area that was already pure white stays pure white rather than clipping into a flat patch, which we confirm by putting a strong leak over a white frame and finding every pixel still at 255. And a dark area lifts toward the leak colour rather than being replaced by it, so shadow detail under a leak is reduced but not destroyed, which is how the real thing behaves. The streaking uses a fixed seed rather than a random source, so the same photograph and settings always produce the same leak and a batch of frames gets a consistent treatment.
What people use it for
Film look photography
A leak is one of the strongest single signals that a photograph came off film rather than a sensor.
Social media posts
Warm edge light reads as nostalgic instantly and survives being viewed small.
Wedding and event photos
A gentle leak on one edge suits the warmth of the occasion without looking like a filter.
Album and single artwork
The accidental quality of a leak suits music imagery, which often wants to look found rather than made.
Travel and summer photos
Leaks are associated with holiday snapshots on cheap cameras, which is exactly the feeling.
Video thumbnails
A bright warm streak draws the eye without competing with a face or a title.
Zines and print
The look reproduces well on cheap paper, where a leak reads as intentional rather than as a printing fault.
Moodboards
Applying one leak across a set of references gives a board a single warm identity.
Six tips worth knowing
Keep it to one edge. One leak is a photograph with a light leak; four is a photograph with a filter on it.
Add streaking. A leak with none of it looks airbrushed, and that is the fastest way to make it read as fake.
Stay warm. Real leaks sit between gold and deep red, because film is most sensitive to red at its edges.
Lower reach is usually more believable. A leak that just catches one edge looks like an accident; one that crosses the whole frame looks deliberate.
Try the no-streaking preset once to see how much that control is carrying.
Add the leak last, after your colour work, so you are not grading a picture that already has extra light in it.
Troubleshooting
It looks like an orange blob
Reduce the width and add streaking. A wide clean band with no breakup is exactly what an airbrushed overlay looks like.
The leak washed out my subject
The reach is too high, so it is crossing the whole frame. Bring it down so the leak stays near its edge.
Bright areas turned flat white
They should not, since screen blending cannot push a pixel out of range. If large areas look flat, the intensity is high enough that they are legitimately saturating; lower it.
It looks the same on every photo
It will, because the streaking uses a fixed seed so that batches stay consistent. Change the position or the edge between images if you want variety.
Frequently asked questions
What is a light leak?
A fault where stray light entered the camera through a gap in the body and struck the film before the picture was taken. It shows as a bright warm streak, and it was originally something photographers tried to avoid.
Why must a leak start at an edge?
Because light got in through a gap in the camera body, so it was brightest at the point of entry and spread inward from there. A glow starting in the middle of the frame is not something a camera can produce.
How is that enforced here?
The leak is anchored to the edge you choose and its contribution decreases at every step as it travels inward, never rising again anywhere along its path. That is checked directly across the frame.
Why are real leaks warm?
Colour film is more sensitive to red toward the edges of the frame, and stray light usually arrives through amber-ish plastic or a light seal. Almost every genuine leak sits between gold and deep red.
What does the streaking control do?
It breaks the leak up. Light coming through an irregular gap and bouncing inside a camera body is uneven, not airbrushed, and a leak with no streaking reads as a graphic overlay rather than an accident.
Why does it look identical on every photo?
Because the streaking uses a fixed seed so a batch of frames gets a consistent treatment. Change the edge or the position between images if you want variety.
How is this different from a glow effect?
A glow effect blooms light that is already in your photograph. This adds light that was never there, entering from an edge, which is a different thing with a different shape.
Why screen blending rather than adding?
Because it can never push a pixel out of range. A strong leak over a pure white frame leaves every pixel at 255 instead of clipping, and shadows lift toward the leak colour rather than being replaced by it.
How many leaks should I use?
One. One leak from one edge is a photograph with a light leak; several from several edges is a photograph with a filter on it, and people read the difference immediately.
It looks like an orange blob
Reduce the width and raise the streaking. A wide clean band with no breakup is exactly what a stock overlay looks like.
Should I add the leak before or after colour work?
After. Grading a picture that already has extra light in it means fighting the leak while you correct everything else.
Is the rainbow option realistic?
Less so than the others. Real leaks are usually one warm colour shifting as it travels. The rainbow ramp is there because the look is popular, not because film did it often.
Which format should I export?
Keep the original for photographs, at quality 90 or above. A leak is a large smooth area of saturated colour, which is exactly the content JPEG bands.
Are my photos uploaded to a server?
No. The leak is composited and exported in your browser using the canvas API. Nothing is sent anywhere.
Is transparency preserved?
Yes for PNG and WebP output. The alpha channel is untouched. JPG has no alpha, so transparent areas are filled with the background colour first.
Can I process a batch?
Yes. Add as many photos as you like and the same edge, position and colour are applied to each.
Can the effect be undone?
No. The added light is baked into the pixels. Your uploaded file is never modified, so keep the original.
Does it add a watermark or need an account?
No to both. No sign-up, no email wall, no daily limit and no watermark on the output.