For a related production step, see the straight and premultiplied alpha lab.
A clean cutout can still look pasted onto a new background. Its edge may remain too isolated from a bright surrounding area. Light wrap is a finishing choice for that boundary, especially when you are combining an AI-created character or product with another image. It does not replace a good matte, a contact shadow or a coherent lighting direction.
What light wrap does in compositing
Light wrap introduces background color near the foreground boundary. Foundry's Nuke documentation describes using the background and foreground together and applying the wrap before the final merge. It distinguishes the spread and strength of the effect, with the default effect kept inside the foreground alpha.
The local tool on this page is our own illustrative blend, not a Nuke node or a physically based light simulation. It operates on encoded RGB values decoded by the browser. Its width and amount controls do not reproduce another application's presets or scene-linear color pipeline.
Try a local PNG composite
Start with the original geometric portrait and gradient, then compare the before checkbox with the wrapped version. For your own images, choose a foreground PNG with visible artwork and some transparency, plus a fully opaque background PNG of exactly the same dimensions. Both must be at most 1024 by 1024 pixels and 10 MB each.
Choose both files, then press Apply selected PNGs. Files are decoded and processed on your device without an upload request. The tool does not resize, key, segment or remove a background. If a pair fails validation, the previous valid pair remains displayed and the message explains the problem.
Understand the original edge blend
The tool blurs the foreground alpha and each background RGB channel with a clamped-edge box filter. It forms an inside-edge weight from twice the positive difference between the original alpha and the blurred alpha, limits that weight to one, then scales it by the selected amount. It blends foreground RGB toward the blurred background color using that weight.
The foreground alpha is preserved. The composite then places that foreground over the original opaque background. The foreground download retains transparency; the composite download is opaque. When Show before is selected, the amount used for both preview and download is zero, even if the amount slider still displays a higher setting.
Download the original algorithm source and the sample foreground and sample background. The example is original mathematical artwork rather than a photographed actor or an AI segmentation result. Browser color decoding and transparent-color rounding can affect pixel values.
Start with the matte and lighting
- Inspect the foreground on a contrasting background and correct missing or unwanted edge detail.
- Match the broad color, contrast and intended lighting direction before applying wrap.
- Use a small width and moderate amount, then compare against zero wrap.
- Check hair, fingers, product lettering and high-contrast corners for lost detail.
- Review the composite at actual delivery size before accepting it.
A wide luminous border can make the cutout more visible. If the edge looks wrong at zero wrap, investigate the matte or source lighting first. For video, inspect the changing edge through the whole shot; this browser tool processes still PNGs and does not guarantee temporal consistency.
Use it in an AI product or character workflow
Prepare the approved product or character image in Clout Image and Video, using an operation supported by the selected model. If you need a separate foreground, obtain and inspect that matte in an appropriate editor. An attractive generated background does not automatically supply the missing alpha channel.
For an original courier placed in a bright archive, keep the brighter background region near the intended edge. Compare a restrained wrap with the untreated composite, and inspect the coat silhouette and face. Do not treat edge blending as evidence that the entire character was illuminated correctly by the new environment.
The rotoscoping guide covers the selection and matte-review stage. The native cutout camera study addresses a different issue: how separated layers behave when the viewpoint moves. Keep those tasks separate in the production brief so a depth problem is not mistaken for an edge-color problem.
Export and inspect both deliverables
Save the opaque composite for review and the transparent wrapped foreground when you need to continue compositing elsewhere. Confirm the dimensions and alpha behavior in the destination editor. Keep the original pair and settings too, especially when the final output will enter a different color-management pipeline.
