All shot on an iPhone 6s+, then processed in Snapseed iOS app. Here follows the magic formula* for B&W conversion in Snapseed:

1. Contrast +10%
2. Drama +20% (don’t be put off when you open this filter and find it defaulted to a deeply unpleasant 90%)
3. Convert to Black & White: ‘Neutral’
4. Apply a colour filter in the Black & White conversion filter, to taste
5. Warmth +8%
6. Vignette: to taste, depending how cluttered your corners are
7. Frame: whatever (but here’s something I have learnt: the more film-like the frame I use, the more I regret it later).

*Not a magic formula, obviously; but a useful shortcut, hopefully. All values above approximate.