Colour negative. Soft, diffuse dye clouds optimised for skin-tone reproduction. Grain concentrated in the midtones.
Measured parameters
Crystal size0.5
Luma RMS0.30
Chroma RMS0.40
DistributionBlue noise · dual octave
Tonal responseShadow 0.25 · Mid 1.0 · Highlight 0.2
Chroma ratio1.75×
Format35mm
ProcessC-41
Visual samples
Portra 400 · graded frame · grain applied
400% crop · midtone region
Tonal response · characteristic curve
Comparison
Clean
BEFOREClean footage — no grain
Portra 400
AFTERSame frame with Portra 400 grain applied