Neon Glow: Turn a Photo Into Glowing Tubes
Edges become tubes and the tubes light the darkness around them. Two stacked glow radii give a tight core and a wide halo, and everything is screen blended, so the background stays exactly the colour you picked.
Drop images here
or click to browse · or paste with Ctrl+V
JPG · PNG · WebP · GIF · BMP · AVIF
Tube colour
From the photo gives each edge the colour of the object it came from, pushed to full strength.
Presets
Your photos are never uploaded. The edge detection, the glow and the export all run inside this browser tab.
People also use
Everything this tool does
A tight core and a wide halo
Two blurs at different radii are stacked, because a single one gives you either the intense region hugging the tube or the broad faint wash, but never both. The measured falloff decreases the whole way out.
Screen blending throughout
The glow can only ever add light. Pixels far from any edge come back exactly equal to the background colour you chose, and tube centres saturate smoothly toward white instead of clipping.
Colour from the photo
Each edge can take the hue of the object it came from, pushed to full strength so a dull red edge glows as a saturated red rather than a brown one.
Real edge detection
Tubes come from a Sobel gradient rather than from a threshold on brightness, so they follow object outlines rather than simply lighting up whatever was already pale.
Four independent controls
Where the tubes go and how they light the room are different questions, so sensitivity, width, spread and intensity are separate sliders rather than one combined amount.
Any background colour
Near black is the classic choice, but a pale background with lower intensity gives the look of tubes mounted on a light wall.
Drag to compare
Before and after share one frame with a slider between them, which is how you judge whether the sensitivity has left you with a sign or a tangle.
Six purpose-built presets
Neon sign, light painting, electric cyan, wireframe, smoky and on pale.
Batch with one ZIP
Light a whole set with identical settings 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 effect is two separate jobs: deciding where the tubes go, which is the sensitivity and width, and deciding how they light the room, which is the spread and intensity.
| Setting | What it does | Try | Good for |
|---|---|---|---|
| Sensitivity 20-40 | only strong outlines | width 2-3 | Clean sign-like results |
| Sensitivity 70-100 | every detail becomes a tube | width 1 | Dense, wiry look |
| Width 1 | fine tubes | spread 8-16 | Detailed subjects |
| Width 3-4 | thick tubes | spread 20-40 | Bold, sign-like |
| Spread 4-10 | tight halo | intensity 70+ | Crisp, controlled |
| Spread 25-40 | wide atmospheric glow | intensity 60-80 | Smoky, cinematic |
| From the photo | each edge keeps its own colour | any | Colourful subjects |
2
stacked glow radii
0
files uploaded
Screen
blend, only adds light
2
colour modes
ZIP
batch download
Free
no account needed
FlipMyFormat vs other neon filters
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Two stacked glow radii, core and halo | ||
| Background stays exactly the chosen colour | ||
| Tube colour taken from the photo | ||
| Separate sensitivity, width, spread and intensity | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How to get neon that looks lit rather than outlined
A neon sign is two things at once: a bright tube, and the light that tube throws onto everything near it. Filters that only do the first give you a coloured outline on a dark background, which looks like clip art. The light is what makes it read as neon, and it has a specific shape: very bright immediately around the tube, falling away quickly, then a much fainter wash extending a long way further. That is why the glow here is built from two blurs at different radii rather than one, because a single blur can give you either the tight core or the wide halo but not both, and the pair together is what your eye recognises. The practical work is mostly in the sensitivity. Neon is made of a small number of continuous tubes, so the fewer lines you have the more it reads as a sign; turn the sensitivity up and every texture in the photograph becomes tube until you have a tangle of wire rather than lighting. Start low, raise it until the shapes you care about are lit, and stop there. The other decision worth making deliberately is the colour mode. Taking the colour from the photograph gives each edge the hue of the object it came from, which suits colourful subjects and produces something closer to a light painting. A single colour is what an actual sign looks like, and it is usually the stronger choice for a portrait or a piece of lettering. Finally, keep the background genuinely dark. Neon on a pale background has nothing to illuminate, and the whole effect collapses.
- 1
Add a photo with clear outlines
Drag it in, click to browse, or paste with Ctrl+V. Subjects with strong shapes work far better than soft or busy ones.
- 2
Set the sensitivity and width
Sensitivity decides how much of the picture becomes tube. Start low and raise it until you have the lines you want and no more.
- 3
Set the glow and export
Spread is how far the light travels, intensity is how bright. Export PNG so the saturated lines stay clean.
What makes a glow look like light
Two radii, because light falls off twice
Look at a photograph of a real neon sign and the light around the tube has two distinct parts. There is an intense region hugging the glass, only a few pixels wide, and there is a broad faint wash that can extend across half the frame. A single blur can produce one or the other. Make it tight and the sign looks like a sticker with a thin outline; make it wide and the bright core disappears into a general haze. Stacking two blurs at different radii and adding them together reproduces both at once, which is why the tubes here look like they are actually emitting. We measure the falloff along a line perpendicular to a tube and it drops steeply for the first few pixels and then trails off slowly, decreasing monotonically the whole way rather than plateauing or ringing.
Screen blending keeps the night black
Every layer here is combined with screen blending, which inverts both values, multiplies them and inverts the result. The useful property is that it can only ever brighten a pixel, never darken one, and adding light to something already at full brightness leaves it there rather than pushing it out of range. That has two consequences worth relying on. The background stays exactly the colour you chose everywhere the glow does not reach, which we verify by checking pixels far from any edge against the chosen background value and finding them identical. And the centre of a bright tube saturates smoothly toward white instead of clipping into a flat patch, which is what the core of a real neon tube does when photographed.
What people use it for
Music and event posters
Neon reads as nightlife instantly, and a neon portrait is a staple of gig and club design.
Social media graphics
Bright saturated lines on black are extremely visible in a feed, which is most of the job.
Logo and lettering treatments
Text photographed or rendered flat turns into a convincing sign, especially in single colour mode.
Cyberpunk and synthwave art
The whole aesthetic is built on glowing lines against darkness, and this produces it from any photo.
Game and UI concept art
Neon outlines suggest holographic displays and heads-up interfaces.
Video thumbnails
The effect survives being shrunk to thumbnail size better than most, because the glow carries the shape.
Party and club invitations
A neon treatment on a venue photo sets the tone without any other design work.
Wireframe and technical looks
High sensitivity with thin tubes turns a photo into something closer to a wireframe render.
Six tips worth knowing
Start with a low sensitivity and raise it slowly. Neon is a small number of continuous tubes, and too many lines becomes a tangle of wire.
Keep the background genuinely dark. Neon on a pale background has nothing to illuminate and the effect collapses.
Single colour reads as an actual sign. Colour from the photo reads as a light painting. Both are good, and they suit different subjects.
Pair a wide spread with a lower intensity. Wide and bright together washes the whole frame out.
Subjects with strong outlines work best. Soft, hazy or very busy photos give the edge detector nothing clean to follow.
Export PNG. Saturated lines on near black is the worst case for JPEG, which adds coloured blocks around every tube.
Troubleshooting
It looks like a coloured outline, not neon
Raise the glow intensity and spread. The light thrown onto the background is what makes it read as lit rather than drawn.
The whole image is a tangle of lines
Sensitivity is too high, so every texture has become tube. Lower it until only the shapes you care about are lit.
The background is not the colour I chose
It will be, everywhere the glow does not reach. If the whole frame is tinted, your spread and intensity are high enough that light is reaching all of it.
The colours look muddy in photo mode
Your subject may be low in saturation, so the edges have little hue to take. Switch to single colour, which is usually stronger for portraits anyway.
Frequently asked questions
How does the neon effect work?
Edges are found with a Sobel gradient and turned into tubes, then those tubes are blurred at two different radii and added back as light on a dark background.
Why two glow radii instead of one?
Because real neon light falls off twice: an intense region hugging the tube and a broad faint wash extending much further. A single blur gives you one or the other, never both.
Why does the background stay exactly the colour I chose?
Because every layer is screen blended, which can only brighten. Where no glow reaches, nothing is added, so those pixels come back exactly equal to your background value.
What does the colour from the photo mode do?
Each edge takes the hue of the object it came from, pushed to full saturation so a dull red edge glows as a saturated red rather than a brown one. It suits colourful subjects.
Which colour mode should I use?
Single colour reads as an actual neon sign and is usually stronger for portraits and lettering. Colour from the photo reads as a light painting and suits colourful, busy subjects.
Why is my image a tangle of lines?
The sensitivity is too high, so every texture in the photograph has become a tube. Neon is a small number of continuous lines, so start low and raise it only until the shapes you want are lit.
Can I use a light background?
Yes, and there is a preset for it, though you should lower the intensity. Neon works by illuminating darkness, so a pale background weakens the effect considerably.
What is the difference between spread and intensity?
Spread is how far the light travels from the tube, intensity is how bright it is. Wide and bright together washes the whole frame out, so pair a wide spread with a lower intensity.
Why use edge detection rather than brightness?
Because tubes should follow object outlines. A brightness threshold would simply light up whatever was already pale in the photograph, which has nothing to do with where a sign maker would bend the glass.
Which photos work best?
Subjects with strong, clean outlines: portraits against plain backgrounds, buildings, lettering, bottles, cars. Soft or very busy photos give the edge detector nothing clean to follow.
Does the tube centre clip to white?
It saturates smoothly toward white rather than clipping into a flat patch, because screen blending leaves an already bright pixel where it is instead of pushing it out of range.
How is this different from the glow effect?
The glow effect blooms light from areas that were already bright in your photo. This creates light where there was none, along edges it detects, which is a different operation with a different result.
Which format should I export?
PNG. Bright saturated lines on a near black background is the worst possible content for JPEG, which surrounds every tube with coloured blocks.
Are my photos uploaded to a server?
No. Edge detection, the glow and the export all run in your browser using the canvas API. Nothing is sent anywhere.
Is transparency preserved?
The output is filled with the background colour, so it is opaque. The alpha channel is left untouched for PNG and WebP output.
Can I process a batch?
Yes. Add as many photos as you like and the same sensitivity, width, spread and colours are applied to each.
Can the effect be undone?
No. The original picture is replaced entirely by the tubes and their glow. 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.