Emboss a picture — turn it into a raised grey relief

How to use Image Emboss

1. Choose one or more images.
2. Set Strength from 10% to 100% (it starts at 100%, a pure grey relief).
3. Pick Save as and Quality.
4. Press Apply and download the files ending in -emboss.

What it does and when to use it

Emboss is a classic filter for making a flat design look physical. Use it to preview a logo as a blind-embossed business card or a stamped metal plate, to make a texture for a game or 3D model, or to give a photo an engraved, sculpted look. It also works as a quick edge check: any outline in the picture shows clearly as a light and dark pair.

Because the full effect is grey, many people tint it afterwards with Image Tint, for example gold or bronze. For outlines without the relief look, Image Threshold gives a hard black-and-white line image.

How it works

On your device, in a Web Worker, the tool:

1. Converts the picture to grey with the standard brightness weights.
2. Runs a 3 × 3 relief kernel over every pixel. The kernel subtracts the neighbours to the upper left (weights −2, −1, −1) and adds those to the lower right (weights 1, 1, 2).
3. Adds 128, so a flat area, where the plus and minus cancel, becomes mid-grey.
4. At Strength below 100%, mixes this relief with the original colours in that proportion.

Pixels at the image border reuse their nearest neighbours, so the edges of the image do not get a false line. Transparency stays as it was.

Worked examples

Values from the tool’s own function.

A flat colour. Any area with no detail becomes (128, 128, 128) at 100%. At 50%, a flat red (200, 30, 30) becomes (164, 79, 79).

A sharp edge. We embossed an image that is black on the left and white on the right. Across one row, the pixels read 128, 128, 128, 128, 255, 255, 128, 128, 128, 128: a 2-pixel bright line at the edge and mid-grey everywhere else. Swap the sides (white left, black right) and the line turns dark instead.

A white square on black. Its top and left edges turn bright and its bottom and right edges dark, so it looks like a raised tile.

Limits and tips

• Noisy photos give a gritty result because every speck counts as an edge; blur slightly first with Image Blur at 1–2 px.
• Thin lines only 1 pixel wide produce a faint relief; bigger shapes work better.
• The embossed file is new and has no EXIF data.