Film Resolution Calculator

Real Hollywood negative sizes → Digital megapixels & K (with correct anamorphic lens behaviour)

80 lp/mm
35mm 4-perf Spherical
Red = 35mm Full Open Gate reference (24.89 × 18.59 mm)

Real-World 35mm Film Resolution – Summary of Credible Sources

Practical measured values with excellent lenses and high-end scanning (drum / Imacon / Flextight).

SourceFilmMeasured lp/mmReal-world equivalent
Roger Cicala (Lensrentals)Velvia 50 / Ektar 10070–85 lp/mm~20–25 MP
Tim Parkin / Joe Cornish (OnLandscape)Fuji Velvia 5080–100 lp/mm (center)22–28 MP
Ken RockwellBest 35mm colour films~80 lp/mm average~22–25 MP practical
Hamrick Software (VueScan tests)4000–5400 ppi scans23–26 MP effective
Imacon/Hasselblad Flextight usersVelvia 50 drum-scannedcommonly 24–30 MP files
Theoretical max (100+ lp/mm)Tech Pan, Adox CMS 20120–160 lp/mm35–45 MP (rarely achieved)

20–25 megapixels is the most widely accepted real-world figure for a perfectly shot and scanned 35mm frame of Velvia 50 or Kodak Ektar 100 with a top-tier prime lens.
Higher numbers are possible only in ideal lab conditions with ultra-slow B&W technical films.