Why do I see this brown patch?

If a brown spot or patch appears on a Polaroid photograph, it is usually a sign that the developing chemicals have not spread evenly across the entire image. When a Polaroid is ejected from the camera, the rollers squeeze the film and spread the developer paste across the frame. If this process does not happen properly, parts of the photograph may not develop correctly, leaving a brown or discolored area.

There are several possible reasons why this can happen. One common cause is expired or dried-out film. The chemicals inside an old film pack can become less effective or partially dry out, preventing them from spreading evenly. Another possibility is dirty camera rollers. Dried chemical residue, dust, or dirt on the rollers can interfere with the even distribution of the developer. Finally, the rollers themselves may be damaged, worn, or misaligned, meaning they do not apply enough pressure to spread the chemicals all the way to the edges and corners of the photograph.

Fortunately, there are a few things you can do to prevent or reduce this problem. First, check and carefully clean the camera's rollers. With the film door open and no film inside, gently remove any dried chemical residue or dirt using a slightly damp cloth or cotton bud. Be careful not to damage the rollers.
It is also important to check the age of your film and avoid using film that has been stored for too long. For the best results, use relatively fresh film and follow the manufacturer's storage recommendations. Unused film should generally be stored flat in a refrigerator, not in the freezer, as cooler storage helps preserve the developing chemicals.