Mobile photographers want film-like color grades but find existing filter apps too generic.
Build an app with authentic Japanese film stock presets (like Fujifilm simulations) and advanced tone curve controls.
Monetize through one-time purchase like the reference app, avoiding subscription fatigue in this market.
MVP could launch with just 3-5 signature looks and basic adjustments before adding pro features.
Risk: competing against free filter apps that dominate casual users.