Characteristics
ScotchChrome™ 640T is the fastest color reversal film available for exposure under tungsten light.
The very high speed makes this film ideal for exposure at low light levels in a wide variety of tungsten light situations from home interiors to sports, circus, theater events, conventions, social events, museum, news documentary and scientific photography.
ScotchChrome 640T is suitable for amateur, professional and industrial applications and is intended for standard E-6 processing.
General Properties
Speed:
ISO 640/29° for exposure in the range of 1 second to 1/10,000 second.
Image characteristics:
This very high speed film exhibits excellent sharpness and medium grain values.
Color reproduction:
Special couplers are used in forming highly saturated yellow, magenta and cyan dyes allowing faithful reproduction of original colors under various illumination levels and light sources.
Color balance:
This film is balanced for tungsten light 3200K. The excellent color balance and the high saturation of the dyes permit optimal results under any tungsten light source from 2850K to 3400K.
Dye stability:
Very stable dyes with high resistance to fading when subjected to repeated or prolonged projection.
Process E-6 compatibility:
This film delivers its high speed using standard E-6 processing times and procedures.
Exposure
The very high speed and the balance for tungsten light allow new picture-taking opportunities without requiring any additional light source.
The film is also balanced to give excellent results when used with an 85B filter in daylight or equivalent light 5500K (electronic flash or blue flash).
Light Sources and Filters
For critical applications, check each light source with a color temperature meter.
| Light source | Recommended Filter | Exposure Adjustments | ISO Speed Rating* |
| Tungston Lamps 3200K | -- | -- | 640/29° |
Stage Lighting/
Quartz Halogen | -- | -- | 640/29° |
| Photoflood Lamps 3400K | -- | -- | 640/29° |
| Daylight 5500K | 85B | + 2/3 stop | 400/27° |
Electronic Flash/
Blue Flashbulbs | 85B | + 2/3 stop | 400/27° |
| Fluorescent Warm White | 50M + 40Y | + 1 stop | 320/26° |
| Fluorescent Cool White | 60R | + 1 2/3 stop | 200/24° |
* With through-lens-metering, the camera ISO setting can be left at 640. The camera will automatically compensate for the filter correction. However internal camera meters do not always have a linear response over the entire spectrum. For critical use, it is advisable to measure exposure without filter at the indicated exposure index listed in the table. Then remount filter and return to lSO 640 to make sure the two measurements (with and without filter) are the same.
Daylight Exposure:
Exposure time 1/500 sec. with 85B
| Lighting Conditions | Lens Aperture |
| Bright or hazy sun with distinct shadows | f/16 |
| Cloudy bright - no shadows | f/8 |
| Overcast sky - open shade | f/5.6 |
Note: For exposure in existing "daylight type" lights, use the very high speed ScotchChrome 1000 balanced for delight 5500K.
Existing Light - Tungsten
Due to the large variety of light conditions, the use of an automatic camera with a through-the-lens metering system or an exposure meter is advisable. The table below is given as a starting point for trial with your equipment:
| Subject | Shutter Speed | Lens Aperture |
| Candlelight close-ups | 1/30 | f/2 |
| Home at night - bright light | 1/60 | f/2.8 |
| Home at night - average light | 1/30 | f/2.8 |
| Bright street light at night | 1/60 | f/4 |
| Shop windows at night | 1/60 | f/5.6 |
| Night or indoor sport events | 1/125 | f/4 |
| Circus show | 1/60 | f/4 |
| Fairs, brightly illuminated par | 1/60 | f/2.8 |
| Church interiors - tungsten light | 1/30 | f/2.8 |
| Museum - tungsten light | 1/60 | f/2.8 |
| Auditorium - theaters | 1/30 | f/4 |
| Fountains- monuments | 1/8 | f/4 |
Reciprocity
For exposure times longer than 1/10 second, it is necessary to compensate for reciprocity characteristics. Suggested data for trial purposes are contained in the following table:
| Exposure Times | From 1/10,000 to 1/10 sec. | 1 sec. | 10 secs. | 100 secs. |
| Exposure Correction | none | +1/2 stop | +1 stop | +2 stops |
| Color Compensating Filter (CC) Correction | none | none | none | CC10Y |
Storage of Films Prior to Processing
Like all color films, ScotchChrome 640T is sensitive to heat, humidity and fumes emitted from chemicals.
Always store unexposed or exposed films in a cool, dry and dark place in moisture-proof containers.
Use film before the expiration date printed on the box.
Do not open the original sealed container until just before using the film.
Avoid leaving film and loaded cameras near heat sources or in hot places such as in a car parked in the sun.
Avoid storing unpackaged film and loaded cameras in high humidity conditions or where the emission of exhaust gases and formaldehyde fumes may occur as these are very harmful to photographic films (aldehyde fumes are often emitted from new furniture, wood glues, laminate adhesive, foam insulation, perfumes, deodorants, aerosol sprays, etc.).
Avoid leaving a partially exposed roll of film in the camera for a long period of time.
Process exposed films promptly to avoid any image deterioration.
In hot, humid climates, keep unexposed and exposed films in a refrigerator in a moisture-proof container at 10°C/50°F or lower.
Storage of Processed Films
The dyes in ScotchChrome 640T are among the most stable used for sensitized material. Yet, like all organic dyes, they may change with time. Humidity, heat and light are the most critical factors in the storage of processed color slides. Always keep processed slides in a cool, dry, dark place. It is advisable to store processed film at a relative humidity not exceeding 40% and a temperature not exceeding 20°C/68°F.
Processing
This film is intended for standard E-6 processing. Push processing is also possible. One-stop push processing (exposure at ISO 1250) results in a very acceptable image with little change in image quality.
We suggest, as a starting point, the following modification to the processing time:
| Exposure Index ISO | | Suggested First Developer Time |
| 1250 | 1 stop push | 8 minutes |
| 640 | Normal exposure | 6 minutes (normal time) |
| 320 | 1 stop pull | 4 minutes |
Applications
ScotchChrome 640T is suitable for various applications in the field of medical, scientific, industrial and commercial photography. The slides are suitable for direct projection, for printing on color reversal paper or as originals for graphic arts applications.
Darkroom Handling
ScotchChrome 640T must be handled in complete darkness. Safelights are not recommended.
Diffuse Granularity: 29 RMS
(Read at a net diffuse density of 1.0)
Note: The sensitometric curves and data represent product tested under the conditions of exposure and processing specified. They represent production coatings and therefore do not apply directly to a particular box or roll of photographic material. They do not represent standards or specifications which must be met by Imation. Imation reserves the right to change and improve product characteristics at any time.
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