Make a mask from a prompt

Last updated: October 26, 2026

Name an object in an image and get a black-and-white mask of it, so an edit or a composite touches that area and nothing else.

Before you start

  • The image is in a session, or in your library ready to add to one.
  • Each run costs Creative Units. See Creative Units for how runs are charged.

Steps

  1. In the session, press ⌘K (Ctrl+K on Windows) and choose Add asset….

  2. Select the image, then click Select 1 asset. It lands on the board.

  3. Hover the image on the board and click View to open it full-size. The viewer shows the file's details on the left and the Actions panel on the right.

  4. In the Actions panel, under Tools, click Mask from prompt. In the box, name what to mask, as plainly as you would point it out to a colleague: "the backpack", "the left boot", "the sword".

  5. Click Make mask. The viewer stays open while it runs.

Result

The mask opens in the viewer as a new file the same size as the image: white where the object shows, black everywhere else. Where something in front covers the object (an arm across a backpack), the mask stops at it, so it holds only what you can see. The original is unchanged, and both sit in the strip on the left of the viewer. The mask is also added to the session's board.

Production tips

  • Name one thing, specifically. When the image has several of the same object, a plain name may pick one of them. Say which: "the left boot", "the sword in her right hand".
  • Mask in a workflow to edit only that area. Add the Mask from prompt node, then wire its Masks output into the Mask input of an Inpaint image, Prompt edit image or Erase object from image node. The edit then stays inside the mask, on every image the workflow runs.
  • Soften the edge before you blend. The mask follows the object's outline closely, which can leave a visible seam once you edit inside it. In a workflow, put a Refine Mask node between the two to grow the mask a few pixels and feather its edge.
  • Want the object itself, not a mask? Use Segment image instead, which cuts the object out on a transparent background. For a whole subject with no prompt, use Remove image background.
  • Take it into your own tools. Download the mask and use it as a layer mask in Photoshop, or as a mask texture in your engine, where white keeps an effect and black hides it.

If something goes wrong

  • The run fails because nothing matched. The model could not find what you named. Use a plainer, more common word for it ("bag" rather than "rucksack"), or describe it by what it looks like.
  • The mask covers the wrong object, or only one of several. Make the name more specific, with a position or a detail that only that object has.
  • The mask misses a thin or small part. Straps, strings and weapon tips are the usual ones. Mask that part on its own with a second run, or grow the mask with Refine Mask in a workflow.
  • The run failed. The new version shows the failure in the strip. Try again.

Related