Start with a dark photo
A bright daytime photo turns into a flat red poster. Night shots and dim interiors keep depth because the shadows have somewhere to go. Photos from blue hour photography work too, since the sky is already dark.
FREE ONLINE PHOTO TOOL
Red light filter.
Moody. Glowing. After dark.
Wash a photo in darkroom red, neon glow or a red flash. Set the intensity, compare with the original and download a free JPG, all in your browser.
This free tool is a photo effect that tints your existing pixels. It is not red light therapy, and it is not the AI relighting used in the Stunna app.
Try it on our sample
Darkroom red · Sample photo; the effect is rendered live above.
Turn the lights red.
Pick a look, then set how red it gets.
or drop it here · JPG, PNG, WebP · up to 20 MB
Free. No signup. No watermark. Up to 3000 px.
Get the full look in Stunna
The Red Light preset in the Stunna app adds a directional red flash with a moody falloff using AI.
Try Red Light in StunnaTry the sample or choose your own photo.
Edited on your deviceNo account neededFree, watermark-free downloads
How to add a red light effect to a photo
Choose a photo
Pick a JPG, PNG or WebP. Night shots, dim rooms and portraits with a visible light source give the most convincing results.
Pick a red look
Try Darkroom red for a single-color print, Red neon glow to keep some original color and bloom the lights, or Red flash to light the centre and let the edges go red.
Set the intensity and download
Lower the intensity to keep natural skin tones, raise it for a full red wash, then save a watermark-free JPG up to 3000 px.
Why everything looks better in red.
A red light look puts a whole photo in red-tinted light: a darkroom safelight, a neon sign, a red-gelled flash in a club. Red sits at the warm end of the spectrum and reads as intimate, nocturnal and a little dangerous, which is why it keeps appearing in night-out photos, album artwork and moody portraits. Red is also a natural fit for Halloween photo ideas.
This free red light filter works with your photo’s own tones. Darkroom red maps shadows to deep maroon and highlights to hot red-orange. Red neon glow keeps more of the original color and adds a red bloom around bright lights. Red flash lights the middle of the frame and lets the edges sink into red. The intensity slider blends between your original and the full effect.
A filter can only recolor what the camera captured. It cannot add a red lamp that was never there or relight a face from the side. That is the job of the AI Red Light preset in the Stunna app, which builds a directional red flash with a night-out falloff.
Try the free toolThree ways to go red
- Darkroom red
- A single-color, almost monochrome print. It simplifies busy scenes and works on almost any photo, in the spirit of a darkroom safelight.
- Red neon glow
- Keeps some of the original color and adds a soft red bloom around lights and bright surfaces. Best on photos that already include signs or lamps. Wet streets from rainy night photography double the glow in their reflections.
- Red flash
- A bright, lightly tinted center with a deep red falloff toward the edges. Made for portraits where the subject sits in the middle of the frame. For a neutral white flash, use the flash filter.
Same night. Different light.
A late-night record shop portrait treated with Darkroom red: a deep red wash, warm highlights and dark shadows. Try Red flash or Red neon glow for other moods.
Try it on your photo
A few details make the difference.
Back the intensity off for skin
Between 55% and 75% keeps skin tones recognizable while the scene still reads as red. At 100% faces become a single red shape.
Control the glow
Glow brightens highlights, which is great for neon and the fairy lights in string light portraits but can blow out windows. Reduce it if bright areas lose detail.
Shoot with the look in mind
Turn the flash off, keep a light source in the frame and stand close to it. The filter has more to work with than in a flat, evenly lit shot.
Get the full look
in Stunna.
The free filter tints the photo you took. The Red Light preset in Stunna goes further with AI: a directional red flash and moody night-out falloff that looks lit, not just colored. Free to download, with optional Pro features.
Free to download. Optional Pro features. AI results vary.
Explore Stunna’s AI looks
Red light filter questions,
answered.
Is this the same as red light therapy?
No. This is a photo effect that tints a picture. It has no connection to red light therapy or to a red screen filter for your phone, and it does not change how your device displays things.
Is the red light filter free?
Yes. Edit and download as many photos as you like without an account or watermark. Downloads are JPG files up to 3000 px on the long edge.
Are my photos uploaded?
No. The effect is rendered in your browser, so the photo stays on your device. Closing the tab clears the session.
How do I get a red flash look?
Choose Red flash, then adjust the intensity. For the most realistic result, start from a night photo with the subject near the center, because the filter brightens the middle and reddens the edges.
What is the difference from the Stunna Red Light preset?
The free tool tints the pixels in your photo. The Red Light preset in the Stunna app uses AI to create a directional red flash with a moody falloff. Results vary, and Pro features are optional.
Related guides
Photo tips and ideas that pair well with this tool.
- Halloween Photo Ideas: 3 Night-Out Flash PhotosCapture the costume, the small details, and the people you came with using a short flash-photo plan.
- String Light Portraits: How to Photograph Fairy LightsGive the face enough light, keep the sparkle behind you, and use four quick checks before choosing the portrait.
- Rainy Night Photography with a Phone: TipsUse reflections, a readable face, and restrained color to give an evening street photo depth.
- Blue Hour Photography with a Phone: Simple TipsBalance a cool sky with city lights, keep the subject clear, and build a small set of evening photographs.