What does it mean when a photogram turns grey?

When a photogram turns grey, it typically indicates that the light-sensitive material used in the process has been exposed to light but not developed properly, resulting in a lack of contrast. This can occur due to insufficient exposure time, improper chemical processing, or the use of a low-contrast photographic paper. The grey appearance suggests that the image lacks the defined blacks and whites needed for a clear representation. To achieve a more vivid photogram, adjustments in exposure and development techniques may be necessary.