- Think about the space. Do you want people to stop & look or do you want it to be "decor" that people walk past?
- Think about the size of your images - hallways are generally narrow, so large images can't be viewed from standing back.
- Think about the lighitng - Is the hallways gloomy? Darker images might not work well.
- Think about your "style" - Do you like minimal & clean with a lot of space between evenly distributed images, or haphazard collections?
- Same for layout - Do you like ordered rows or uneven spacing?
Once you've made a decision on how many, how big and how they look, consider blu-tacking your images to the wall for a week to see if you like the arrangement or it bugs you (or other people using the house) before framing up and mounting properly.
Consider image rotation. Rather than displaying (e.g.) 20 tiny images for 10 years, how about 5 images a bit more spaced out, but change them every 12 months?
There's no right answer Ronin. Your house, your wall, your photos, your taste. But it is worth thinking about.
Many thanks for you excellent advice. I’ve got a few ideas now and have started placing on the wall. I’m using a4 and 7 x 5 ikea frames which are very light. I’ve ended up using a thin strip of 3m Command Strips on the top part of the frame. So far has stayed up well. When I’ve finished I’ll upload the photo.