soap film(n = noun.artifact) - a film left on objects after they have been washed in soap;
is a kind of film

bar soap, bath soap, castile soap, cling film, collage film, documentary film, face soap, feature film, film, film advance, film clip, film company, film director, film editing, film fern, film festival, film industry, film maker, film making, film over, film producer, film projector, film star, film writer, green soap, invert soap, leather soap, liquid soap, motion-picture film, movie film, orthochromatic film, panchromatic film, photographic film, pilot film, plastic film, roll film, saddle soap, shaving soap, silent film, soap, soap bubble, soap dish, soap dispenser, soap flakes, soap opera, soap pad, soap powder, soap tree, soft soap, sound film, stag film, toilet soap, x-ray film