What makes a private slide worth preserving?

An ordinary room, imperfect framing, someone looking away from the lens. Family slides and amateur photography often preserve a social atmosphere that polished editorial photographs remove.

What do you find most compelling: the colour, the setting, the unfamiliarity of the era, or the accidental composition?

There is no need to identify the person in the picture. Sometimes a photograph is more interesting when we leave the biography alone.