Silverlog Reciprocity

Silverlog Reciprocity calculates corrected exposure times for long exposures on film, compensating for reciprocity failure — the point where film loses sensitivity during extended exposures.

HOW IT WORKS
Select your film stock from a comprehensive database covering Kodak, Ilford, Fujifilm, Fomapan, CineStill, Lomography and more. Enter your metered exposure time and instantly see the compensated time you should actually use.

Calculations use manufacturer-published reciprocity data or established empirical formulas, and each correction shows which method was used: interpolation from a published data table, or a Schwarzschild exponent formula.

FEATURES
• Over 70 film stocks with reciprocity data
• Instant calculation — no submit buttons, results update live
• Method shown with each correction — data table or Schwarzschild exponent
• Built-in countdown timer for the corrected exposure
• Favourite and recent films for quick access
• Works offline — no internet connection needed
• Clean, focused interface designed for use in the field
• Dark mode support

BUILT FOR PHOTOGRAPHERS
Whether you're shooting Velvia at sunset, Tri-X under moonlight, or Delta 3200 in a cathedral, Silverlog Reciprocity gives you the corrected time without fumbling with charts or guesswork.

Part of the Silverlog photography toolkit. No account required. No data collected.