Film specifications#
- Manufacturer
- 3M
- Film
- Dynachrome 25
- Type
- Color slide film
- Speed
- 25
- Process
- K-11
- Formats
- 135
- Base
- Triacetate
- Made in
- Italy
- Status
- Discontinued
Character & history#
Color reversal film for daylight, knock-off Kodachrome based on expired Kodak Patents.
Description adapted from Wikipedia’s “List of discontinued photographic films” (CC BY-SA 4.0).
Exposure guide at ISO 25#
Sunny 16 for this film: f/16 at 1/25 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 | — | 1/1000 s | 1/250 s | 1/60 s |
| EV 15 · Bright sun | 1/2000 s | 1/500 s | 1/125 s | 1/30 s |
| EV 14 · Hazy sun | 1/1000 s | 1/250 s | 1/60 s | 1/15 s |
| EV 13 · Cloudy-bright | 1/500 s | 1/125 s | 1/30 s | 1/8 s |
| EV 12 · Overcast / open shade | 1/250 s | 1/60 s | 1/15 s | 1/4 s |
| EV 10 · Sunset | 1/60 s | 1/15 s | 1/4 s | 1 s |
| EV 8 · Bright interior | 1/15 s | 1/4 s | 1 s | 4 s |
| EV 5 · Home interior at night | 0.5 s | 2 s | 8 s | 30 s |
| EV 3 · City street at night | 2 s | 8 s | 30 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.
Similar films#
Other color slide film around ISO 25.
- ADOX C 15 ISO 25 · disc.
- Agfa Agfacolor Umkehrfilm K ISO 25 · disc.
- Agfa Agfacolor Umkehrfilm T ISO 25 · disc.
- Efke Color RD15 ISO 25 · disc.
- Ferrania Ferraniacolor ISO 25 · disc.
- ORWO UT 15 ISO 25 · disc.
- Ilford Colour Film F ISO 20 · disc.
- ORWO UK 14 ISO 20 · disc.
- Agfa Umkehrfilm Ultra T ISO 32 · disc.
- Foma Fomachrom D 16 ISO 32 · disc.
- Fujifilm Fujicolor Reversal Professional Tungsten Type ISO 32 · disc.
- Ilford Ilfochrome ISO 32 · disc.
- ORWO UT 16 ISO 32 · disc.
- ORWO UT 16 ISO 32 · disc.
More 3M films#
Frequently asked questions#
What ISO is 3M Dynachrome 25?
25 — set your meter to ISO 25 for box speed.
Is 3M Dynachrome 25 still made?
No, it has been discontinued (1960s–1970s).
How do I develop 3M Dynachrome 25?
K-11 process.
Is 3M Dynachrome 25 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