Turn a picture into a grey relief that looks pressed into metal or stone, with the light coming from any of eight directions. Adjust the depth and download.
Runs a 3 × 3 directional kernel over the image. For every pixel it subtracts neighbours on one side and adds neighbours on the other, then centres the result on mid-grey. Flat areas become grey, edges facing the light become bright ridges and edges facing away become dark grooves, which is exactly how a raised stamp looks under a lamp. The kernel changes with the light direction you pick, so the same photo can read as raised or sunken.
A 1600 × 1200 product photo of a coin: Top left light at 50 percent strength gives a clean pewter relief where the lettering stands out and the flat field is an even 50 percent grey. Flipping to Bottom right makes the same lettering look engraved rather than raised. At 100 percent strength fine texture turns into harsh black-and-white speckle, which suits grunge posters but not photos. With Grey only off, faint colour fringes remain along strong colour edges, useful for a subtle metallic-paint look.
Use it for watermarks, letterpress and foil mock-ups, background textures, stamp and seal designs, and to reveal surface detail in scans of coins, textiles or paper. It is a poor choice for portraits, where skin becomes lumpy, unless that is the effect you want. If you want to keep the picture’s colours while adding depth, use Color Emboss; if you only need the outlines, Edge Detection gives a cleaner line map.
Light direction picks one of eight kernels; opposite directions swap raised for sunken. Strength scales the edge response before it is added to mid-grey; 25 is a whisper, 50 is a typical pressed-metal look, 100 clips to pure black and white on strong edges. Grey only converts the result to luminance so no colour fringes remain. The one-pixel border of the output is flat mid-grey because the kernel needs neighbours on all sides.
Why is everything grey? That is the emboss look: flat areas have no edges, so they land on mid-grey. Only edges become light or dark. For a coloured version use Color Emboss.
Which direction should I choose? Top left is the convention for a raised look because we expect light from above and to the left. Pick the opposite corner for an engraved or sunken feel.
Can I use the result as a watermark? Yes. Emboss at 40 to 60 percent, then overlay it on the photo at low opacity with Overlay Image. The relief shows without hiding the picture.
Why is the border a flat line? The 3 × 3 kernel needs a neighbour on every side, so the outermost pixel ring is filled with mid-grey. Crop one pixel off with Crop Image if it matters.
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