The cut-out decides the result
Hard-edged products such as boxes, bottles and electronics take a clean path. Soft edges need a proper alpha mask: hair, fur, knitwear, feathers, frayed fabric. Transparent and translucent products are the hardest, because the new background has to show through glass or liquid with believable refraction and tint, not as a pasted-in grey. Check edges at full size against both a dark and a light background, since halos hide on one and show on the other. Deliver cut-outs as PNG or TIFF with transparency; JPEG cannot carry an alpha channel, so a JPEG always has something behind the product.
Shadows, reflections and light that sell realism
A product without a contact shadow floats. Every object needs a thin, dark occlusion line where it meets the surface, then a cast shadow whose direction, length and softness match the light in the new scene. Glossy floors and tabletops need a faded reflection. The product reflects its surroundings too: a chrome kettle still showing the softboxes of the original shoot gives itself away in a kitchen. Match the camera height and horizon line, colour temperature and depth of field, so a pin-sharp product does not sit in front of a background that implies a different lens.
Colour spill and outpainting for new ratios
Coloured backdrops bounce light onto a product's edges: green from a chroma screen, warm tones from a wooden table, blue from a sky. Remove that spill, then add a little of the new scene's colour back, because an object in a green garden picks up some green. Outpainting, extending a scene beyond its frame, turns a square packshot into a 16:9 banner or a 9:16 story. It is also where generators invent things at the edges: a second product, a duplicated handle, a sign in nonsense lettering. Check the new margins as carefully as the centre, and never let the extension crop or redraw the product.
Marketplace rules and background changes at scale
Marketplaces want main images plain, not busy. Amazon's main image must sit on pure white, and generated backgrounds can land on an off-white that fails automated checks and can get a listing suppressed, so sample the pixel values rather than trusting the screen. Google Shopping rejects promotional overlays and watermarks. Scenes belong in secondary images, ads and social posts. In Synthetic White, background changes run in batches from a product feed, with product-lock keeping the product pixel-accurate while only the scene changes, so one product can be set into white, seasonal and regional backgrounds from the same feed.
Updated 25 September 2026