Film specifications#
- Manufacturer
- Efke
- Film
- Color RD20
- Type
- Color slide film
- Speed
- 80
- Process
- E-4
- Formats
- 135
- Base
- Triacetate
- Made in
- Italy, Yugoslavia
- Status
- Discontinued — replaced by Color RD21
Character & history#
Color reversal film for daylight. Rebranded 3M Color Slide.
Description adapted from Wikipedia’s “List of discontinued photographic films” (CC BY-SA 4.0).
Exposure guide at ISO 80#
Sunny 16 for this film: f/16 at 1/80 s in bright sun. Negative film tolerates 2–3 stops of overexposure; slide film needs accuracy within about ⅓–½ stop.
| Light | f/2 | f/4 | f/8 | f/16 |
|---|---|---|---|---|
| EV 16 · Snow / beach, bright sun | — | 1/3200 s | 1/800 s | 1/200 s |
| EV 15 · Bright sun | — | 1/1600 s | 1/400 s | 1/100 s |
| EV 14 · Hazy sun | 1/3200 s | 1/800 s | 1/200 s | 1/50 s |
| EV 13 · Cloudy-bright | 1/1600 s | 1/400 s | 1/100 s | 1/25 s |
| EV 12 · Overcast / open shade | 1/800 s | 1/200 s | 1/50 s | 1/13 s |
| EV 10 · Sunset | 1/200 s | 1/50 s | 1/13 s | 0.3 s |
| EV 8 · Bright interior | 1/50 s | 1/13 s | 0.3 s | 1.3 s |
| EV 5 · Home interior at night | 1/6 s | 0.6 s | 2.5 s | 10 s |
| EV 3 · City street at night | 0.6 s | 2.5 s | 10 s | 30 s |
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.
Similar films#
Other color slide film around ISO 80.
- Flic Film Chrome ISO 100
- Fujifilm Fujichrome Provia 100F ISO 100
- Fujifilm Fujichrome Velvia 100 ISO 100
- Ilford Ilfochrome 100 ISO 100
- Kodak Ektachrome E100 ISO 100
- Rera Chrome 100 ISO 100
- Agfa Agfacolor CK ISO 80 · disc.
- Foma Fomachrom D 20 ISO 80 · disc.
- Foma Fomachrom-II D 20 ISO 80 · disc.
- Foton Fomachrom II D 20 ISO 80 · disc.
- ORWO UK 20 ISO 80 · disc.
- ORWO UT 20 ISO 80 · disc.
- 3M Color Slide 64 ISO 64 · disc.
- 3M Dynachrome 64 ISO 64 · disc.
- Agfa Agfachrome 64 ISO 64 · disc.
- Agfa Agfachrome CT 64 ISO 64 · disc.
- Fujifilm Fujichrome 64 Professional T ISO 64 · disc.
- Fujifilm Fujichrome 64T ISO 64 · disc.
More Efke films#
Frequently asked questions#
What ISO is Efke Color RD20?
80 — set your meter to ISO 80 for box speed.
Is Efke Color RD20 still made?
No, it has been discontinued (1976–1979).
How do I develop Efke Color RD20?
E-4 process.
Is Efke Color RD20 available in 35mm?
Yes — formats: 135.
Sources & licences#
- Wikipedia: List of discontinued photographic films — CC BY-SA 4.0
Last updated October 03, 2026 · How we calculate · Sources