Sepia Image

Sepia image effect: give any photo a warm, vintage tone

Sepia is the warm brown of old photographs. The name comes from the ink of the cuttlefish Sepia, and the look from a darkroom process: sepia toner converted the silver in a print into silver sulfide, which looked brown and lasted far longer. Today it is the quickest way to give a picture a nostalgic, timeless feel. The sepia image tool applies the classic sepia colour matrix used by CSS filters, or a duotone that maps shadows and highlights to two colours you choose.

A strength slider blends between the original and the full effect, the before/after split shows exactly what changed, and batches of photos are processed at full resolution in your browser and saved as a ZIP. Transparency in PNGs is preserved.

How to use the Sepia Image

1. Add the photos you want to tone by dragging them in, clicking the upload area or pasting with Ctrl+V.
2. Choose a Style: Classic sepia for the familiar CSS look, or Duotone for a softer gradient that never clips.
3. Set the Strength. 100% is fully toned; 30–60% keeps a hint of the original colours.
4. In Duotone, pick your own Shadow tone and Highlight tone, or start from the Coffee or Selenium presets.
5. Compare with the split view and download, or save all photos as a ZIP.

Sepia Image features

The sepia formula

Classic sepia multiplies each pixel’s red, green and blue values by a fixed matrix — the one published in the W3C Filter Effects specification for sepia(100%):

• R′ = 0.393 R + 0.769 G + 0.189 B
• G′ = 0.349 R + 0.686 G + 0.168 B
• B′ = 0.272 R + 0.534 G + 0.131 B

Why bright areas turn cream

The three rows are almost proportional to one another, so every colour lands on nearly the same brown hue — the original colours disappear. The rows add up to 1.351, 1.203 and 0.937, so the result is always warmer than the input. A mid-grey of 128 becomes (173, 154, 120), a light brown. White would need a red value of 345, so it is clipped to (255, 255, 239): a cream highlight with no detail left. That clipping is why bright skies can look flat in classic sepia.

For a strength a below 100%, each coefficient is blended with the identity matrix exactly as the specification describes — the red-from-red coefficient becomes 0.393 + 0.607 × (1 − a), and so on — so 0% leaves the image unchanged.

Duotone: a gentler, adjustable sepia

Duotone first measures the luma of each pixel, Y = (0.2126 R + 0.7152 G + 0.0722 B) ÷ 255, then picks the colour at that position on a gradient from the shadow tone to the highlight tone: out = shadow + (highlight − shadow) × Y. Black becomes exactly the shadow colour and white exactly the highlight colour, so nothing clips and paper whites stay creamy instead of burnt. Changing the two colours recreates other historical tones: cool, purplish selenium, warm coffee, or the blues of a cyanotype.

Tips

• Sepia works best on photos with clear light and shade; if the picture is flat, add a little punch with the contrast tool first.
• For a neutral black-and-white instead, use Grayscale Image.
• A single-colour tint with any hue is also possible with Colorize in Image Hue.
• Combine with vignettes and other looks in Image Filters.