Add a Contact Shadow After Extracting an Object from an Image
An extracted jar has a clean outline, but it seems to float above its new tabletop. Moving it downward does not help: the missing cue is the small area of darkness where its base meets the surface.
To add a contact shadow after extracting an object from an image, paint a narrow, soft shadow on a separate layer beneath the object. Match it to the actual contact area, then adjust its opacity against the intended background. Keep any broader cast shadow separate so you can control the two independently.
This suggested Photoshop desktop workflow uses an opaque ceramic jar on a matte tabletop under soft studio lighting. It suits a simple product composition; glass, suspended objects, and strong directional lighting need different treatment.
Check whether the shadow is actually missing
Save a working copy and keep the original photograph available. Hide the jar layer, then toggle the remaining layers individually.
Look for an existing shadow in three places:
- On its own transparent layer beneath the jar.
- Attached to the jar's cutout.
- Embedded in the background photograph.
If a suitable shadow already exists, try restoring its visibility before painting another. Doubling a faint original shadow can create a dark ring that looks like dirt around the base.
Inspect the jar on the intended tabletop rather than judging only against the transparency checkerboard. A shadow can be present but difficult to see on a patterned preview.
The site's object separation guide recommends recreating a missing shadow on a separate soft layer. The procedure below develops that specific finishing task after extraction.
Separate contact from the longer cast shadow
For this example, distinguish two visual components.
The contact shadow is the tight dark region immediately beneath the jar. It establishes where the base touches the tabletop. The cast shadow extends farther across the surface, with its direction and shape influenced by the lighting and object.
Start with the contact region. A broad blurred oval may add darkness yet still leave the jar looking suspended if there is a bright gap directly beneath its base.
Study the source photograph for clues. Where does the jar meet the surface? Is the darker area concentrated toward one side? Does the scene have soft light or a sharply defined shadow?
Use those observations as a starting point, then account for the destination scene. An original shadow pointing left will conflict with nearby objects whose shadows point right.
Prepare a simple layer stack
Image to Layer's download options list AI RGBA layer decomposition with PNG and PSD downloads. These formats provide material for further editing; the page does not promise a separate, reusable contact shadow for every object.
In Photoshop, place the isolated jar above the destination background. Create a blank pixel layer between them and name it Jar contact shadow. If you later need a broader shadow, give it another layer below the contact layer.
Your working order, from top to bottom, should be:
- Jar cutout.
- Jar contact shadow.
- Jar cast shadow, if needed.
- Tabletop background.
Keep a full-image reference hidden while painting. Otherwise, its original jar or shadow may conceal what your new layers actually contribute.
Select the contact-shadow layer's pixel thumbnail. Painting on the jar itself would make subsequent shadow corrections unnecessarily difficult.
Paint the contact area in small passes
Choose the Brush tool and a soft round brush. Set a dark, neutral foreground color for the first trial. Keep the brush's painting mode at Normal and use a low brush opacity, such as 10–20%, as an adjustable starting point.
Adobe documents foreground-color painting, brush softness, opacity, and flow in its painting tools guide. Releasing the mouse and painting another stroke can build additional opacity, so repeated passes may become darker than expected.
Paint a short stroke along the underside of the jar, with much of the stroke tucked behind the object. Let only a narrow soft edge extend onto the tabletop. Follow the visible base rather than drawing a wide circle around it.
For example, if the jar's base is roughly 240 pixels wide, try a brush around 12 pixels across for the initial contact stroke. This is a trial scale for that example, not a universal setting. Reduce it if the shadow protrudes like a thick border.
Toggle the shadow layer. The jar should gain a sense of contact without acquiring an obvious black outline. Undo uneven passes instead of covering them with more paint.
Adjust blending and strength
Try Multiply as the contact layer's blend mode, then lower the layer opacity until the darkness fits the scene. Adobe's blending-mode documentation explains that Multiply darkens the underlying colors; white has no effect, while black produces black at full strength.
Multiply does not determine the right shadow shape or brightness. A thick, opaque stroke can still overwhelm the tabletop texture.
Judge the contact region alongside other dark details in the photograph. If a softly lit cream jar has a base shadow darker than every nearby crevice, reduce its strength. If the base still appears detached, check the shadow's position before increasing opacity.
Also examine both ends of the stroke. Abrupt endpoints often reveal the brushwork. Shorter, lighter finishing strokes can soften those transitions without enlarging the whole shadow.
Add broader softness only when the scene needs it
If the contact stroke looks too isolated, create the optional cast-shadow layer beneath it. With a larger soft brush and low opacity, build a restrained patch extending away from the light source.
Keep this patch weaker and broader than the tight contact region. In the softly lit jar example, a modest spread may be enough. Do not add a long dramatic shadow unless the lighting supports it.
Photoshop also offers a Drop Shadow layer effect through the FX menu, with controls for direction, distance, and other properties. Adobe explains these in its drop-shadow guide. That effect is useful for many graphic elements, but an offset of the whole jar silhouette may not describe its contact with a tabletop convincingly.
For a long, recognizable cast shadow, plan a separate construction based on the object's shape and the receiving surface. A painted contact patch alone does not solve that larger task.
Diagnose the result at delivery size
Check the composite at 100% zoom and at its intended display size.
If the jar still floats, look for a light gap between the base and the darkest part of the shadow. If it looks surrounded by soot, reduce the shadow's width or opacity. If a dark double edge appears, check again for an original shadow attached to the cutout.
Hide the jar briefly to inspect the painted layers. Look for stray marks and sudden changes in density, then restore the jar to assess the actual composite.
Save the layered PSD and reopen it. Confirm that the contact shadow can be adjusted independently. When moving the jar, select its associated shadow layers too, then reassess their placement against the new surface. Finally, inspect the exported composition: the base should feel connected to the tabletop without the added shadow becoming the first thing you notice.
