C-41 Process
The standardised chemical process for developing colour negative film.
Formula / rule
3′15″ at 38 °C
Measured in
minutes at °C
In depth
C-41 runs at a tightly controlled 38 °C, far hotter than black and white processing, because the reaction must be fast and consistent across every lab in the world. That standardisation is its point: any C-41 film processed anywhere yields comparable results, which is what made mass-market colour photography possible.
Examples in practice
A roll processed in a high-street minilab and one processed at home in a heated bath produce matching negatives.