Apply a duotone gradient to any image
Map your photo's luminance to a gradient between two custom colours — a Spotify-style cover effect that runs in your browser.
image/* · runs locally · nothing uploaded
How it works
Pick an image, tune the options, then download the result. Everything runs in your browser.
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Pick an image
Photos with clear shadows and highlights work best.
Files stay in memory as an
HTMLImageElement— the original bytes are never uploaded, and EXIF metadata is preserved until you explicitly transform it.uploadcanvaslocaldecodeinput · bytesimage · loadedportrait.jpg
loaded · decodedcanvas · ready - 02
Choose two colours
Shadow maps to the darkest pixels; highlight to the brightest.
Encoder quality is exposed where the format supports it — JPEG and WebP get a
0–1quality slider; PNG is lossless. Options re-render the canvas immediately.colouroptionslive previewencoderqualitypair · tunableshadow + hi · live#1d3557 ↔ #f1faee
options applied · liveencoder · live - 03
Watch it remap
Each pixel's luminance becomes a position along the gradient.
Pixel work runs on the Canvas 2D context —
drawImageresamples with the browser’s bilinear filter andgetImageData/putImageDataback per-pixel passes.maprenderCanvas 2Dpreviewpx-perfectlerp · resampledrec601 · px-perfecty = 0.299r + 0.587g + 0.114b
preview · livepx-perfect - 04
Download
Grab the PNG with full transparency preserved.
Downloads ship via a hidden anchor with an object URL — no server round-trip, and the file on disk is untouched. The output filename inherits a sensible suffix.
exportdownloadblobclient-sideobject URLok · blobready · savedphoto-duotone.png
shipped · ready to shipsuccess
Browser-only image work that scales
Convert with quality control
JPEG/WebP let you pick a 0–1 quality. Default 0.92 is a good compromise of size and visible quality.
PNG isn’t free
Use PNG only for transparency or sharp edges. For photos, WebP is smaller at the same perceived quality.
Strip EXIF for privacy
Photo EXIF often contains GPS, camera model, and timestamps. Strip before sharing public uploads.
Watch the colour profile
Convert to sRGB before web export. Wide-gamut images render oversaturated in non-managed browsers.
AVIF when it’s available
AVIF beats WebP on size at the same quality. Detect support via <picture> with fallbacks.
Lazy-load below the fold
Add loading="lazy" on <img>. The browser handles scheduling — no IntersectionObserver needed.
When to use this tool
Common workflows it speeds up.
Album / podcast covers
Spotify-style duotones in two clicks. Decoded into a Canvas 2D context — original bytes never leave the tab, so you can process customer-uploaded photos, internal screenshots, or sensitive diagrams without privacy concerns.
px-perfectEditorial mood
Unify hero photography across a feature. Encoders expose quality 0–1 where the format supports it (JPEG, WebP); PNG and AVIF stay perceptually lossless. Pick 0.85 for web, 0.95 for archival, 0.7 for thumbnails.
quality-tunableBrand colour overlay
Tint stock photos in your palette. Pair with the EXIF Stripper before sharing user-uploaded photos publicly. Camera serial numbers, GPS coordinates, and timestamps often hide in image metadata and leak more than the picture itself.
format-awareSection dividers
Use as a tinted backdrop behind text. Output preserves colour profile (sRGB) so it renders consistently across browsers, monitors, and print pipelines. Wide-gamut workflows can opt into Display P3 for modern Apple devices.
EXIF-safeQuick mockups
Faster than reaching for Photoshop. Re-runs only on option changes, never on window resize, so the canvas stays responsive on large images. drawImage uses the browser's bilinear filter for fast resampling.
client-sideSocial posts
Cohesive Instagram or LinkedIn feeds. Downloads as .png, .jpg, .webp, or .avif with the correct MIME so editors apply native handling on save. The filename inherits a sensible suffix derived from the input.
compression-readyFrequently asked questions
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