Color slide film · Discontinued

3M Ferrania CR50A

3M Ferrania CR50A is a color slide film rated at ISO 50, developed in Agfacolor. Below: specs, an exposure guide and similar stocks.

ISO 50AgfacolorDiscontinued135120
ISO 50
Box speed
Color slide
Type
Agfacolor
Process
Discontinued
Status
c1967–c1975
Years made

Film specifications#

Manufacturer
3M
Film
Ferrania CR50A
Speed
50
Process
Agfacolor
Formats
135, 120
Base
Triacetate
Made in
Italy
Status
Discontinued

Character & history#

Color reversal film for artificial light.

Description adapted from Wikipedia’s “List of discontinued photographic films” (CC BY-SA 4.0).

Exposure guide at ISO 50#

Sunny 16 for this film: f/16 at 1/50 s in bright sun. Negative film tolerates 2–3 stops of overexposure; slide film needs accuracy within about ⅓–½ stop.

Lightf/2f/4f/8f/16
EV 16 · Snow / beach, bright sun—1/2000 s1/500 s1/125 s
EV 15 · Bright sun—1/1000 s1/250 s1/60 s
EV 14 · Hazy sun1/2000 s1/500 s1/125 s1/30 s
EV 13 · Cloudy-bright1/1000 s1/250 s1/60 s1/15 s
EV 12 · Overcast / open shade1/500 s1/125 s1/30 s1/8 s
EV 10 · Sunset1/125 s1/30 s1/8 s0.5 s
EV 8 · Bright interior1/30 s1/8 s0.5 s2 s
EV 5 · Home interior at night1/4 s1 s4 s15 s
EV 3 · City street at night1 s4 s15 s> 1 min

Long exposures#

Most films suffer reciprocity failure beyond about 1 second: they need more exposure than the meter says. As a rule of thumb add ⅓–1 stop for 1–10 s and 1–2 stops beyond 10 s for older emulsions; modern T-grain films (and Fuji Acros) need much less. Check the manufacturer's datasheet.

More 3M films#

Frequently asked questions#

What ISO is 3M Ferrania CR50A?

50 — set your meter to ISO 50 for box speed.

Is 3M Ferrania CR50A still made?

No, it has been discontinued (c1967–c1975).

How do I develop 3M Ferrania CR50A?

Agfacolor process.

Is 3M Ferrania CR50A available in 35mm?

Yes — formats: 135, 120.

Sources & licences#

Last updated October 03, 2026 · How we calculate · Sources

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