Revive the inheritance: Facts on the development of Kodak Eastman ECN-1 Film 5251 50T

Today we are devoting ourselves to research and understanding analog film processes. A particularly fascinating project is the development of the Kodak 5251 50T Eastman Color Negative Films -A historical movie from the 1960s, which was originally designed for the now outdated ECN-1 process. This article illuminates the technical challenges and our practical experience in reviving this unique film material.

The Kodak 5251 50T: an artificial light film with history

The Kodak 5251 50T is one Tungsten-balanced (tungsten-balanced) color negative film With a nominal color temperature of 3200 Kelvin (3200K) and an original sensitivity of 50 ASA/ISO.¹ It was used in cinema production from 1962 to 1969.¹

Working with a 60 -year -old film harbors specific challenges:

• Loss of sensitivity: The latent image of the film fades for decades, which means a significant loss of sensitivity to light.²
• Unpredictability: Due to the unknown storage conditions, the results are difficult to predict over so long periods.³
• Remjet layer: Like all movies, the 5251 has a remjet layer on the back that has to be removed before development.

Eastman 5251 50T 1

Remjet removal: a necessary first step

The Remjet layer is a black, carbon-based layer, the halation (atriums), prevent static discharges and scratches. It must be removed before developing to avoid contamination of the chemistry and stains on the film.

Our proven remjet removal recipe:

• Chemie: 100g sodium carbonate (washing soda) per 1 liter of water.
• Temperature: 25-30°C.
• Time: 2 minutes.
• Agitation: Continuous tilting of the tank.
• After -preparation: After emptying the bath, rinse the container 5x with water until the water is clear.

Note: The Remjet layer on older ECN-1 film is often easier to remove than with modern vision 3 film.⁴

The ECN-1 process: historical specifications

The original ECN-1 process, as described in the SMPTE Journal by Wesley T. Hanson Jr. (March 1952), was a low-temperature process.⁵

Original ECN-1 process steps (SMPTE Journal, 1952):

Note: The “Negative Color Development” at 70 ° F (approx. 21 ° C) was the only step marked as a “critical”.

Our successful method: direct ECN-2 development at low temperature

Despite the historical incompatibility between ECN-1 film and ECN-2 chemistry ⁶, we have found an effective process that delivers good results.

Unser “Sweet Spot” Workflow:

• Exposure: The film was as ISO 1.5 expenses to compensate for the age -related sensitivity loss.
• Development: Direct development in ECN-2 chemistry (without prior SW development or re-halogenization).
  • Color development: 15 minutes at 24 ° C, alternatively 18 minutes 30 seconds at 22 ° C
  • Bleaching: 8 minutes.

Result: The negatives were well exposed and showed No noteworthy color shift. This is remarkable because ECN-2 chemistry is optimized for 41.1 ° C ⁶, the ECN-1 emulsions would melt at this temperature.⁷ The 24 ° C seem to be an optimal compromise in which the old emulsion remains stable and the ECN-2 chemistry enables balanced dye formation. The pictures show a good density and color rendering, as can be seen in the example pictures.

Challenges and optimizations: density and color balance

In the case of further experiments, especially with longer development times or older developers, color shifts occurred.

Analysis of the problems:

• Overlapping of colors: An extension of the color development time (e.g. to 18 minutes at 24 ° C) can lead to an overdevelopment of the layers of paint, which is expressed as a “crossover” effects (different color balance in lights and shadows).
• Exhausted developer: An aging color developer (e.g. 3 weeks old) loses activity and can lead to underdevelopment (especially the blue channel, i.e. the yellow dye layer) and color shifts.
• Overwhelming bleaching: A length of stay in the bleaching fixer (e.g. 15 minutes) can lead to fading the dyes (dye whitening), which makes the colors appear pale and shifted.⁸

Eastman 5251 50T 2

Our recipes for the solutions (tested and proven)

1. Remjet Removal Bad:

• Chemie: 100g sodium carbonate (washing soda) per 1 liter of water.
• Temperature: 20°C.
• Time: 2 minutes.

2. Hypo Clearing Agent:

• Chemie: 20g sodium sulfite water -free per 1 liter of water.
• Temperature: 20°C.
• Time: 2 minutes.
• A notice: Essential to avoid red coloring (dichroic veil) by reaction of fixing remains with the bleaching bath.⁸

3. RE-HALOGING BLEICHBAD (for the optional SW pre-development workflow):

• Chemie: 5 g/l potassium hexacyanoferrat (III) and 10 g/l potassium bromide.
• Temperature: 20°C.
• Time: 3-5 minutes (until everything has disappeared black silver).
• A notice: The developed metallic silver of the SW image again converts this bath into light-sensitive silver halide.⁸

Optimized workflow with initial black and white development

Based on our comprehensive tests and knowledge, we recommend this optimized workflow for the Kodak 5251 50T:

1. Remjet Removal Bad: 2 min at 20 ° C (100g sodium carbonate/l). 5x rinsing to clear.
2. SW development (optional, for more density): 12 min in HC-110 1:31 at 20 ° C.
3. Water as a stop: 1 min.
4. Fixing bath (SW): 5-7 min in Ammoniumthiosulfat bei 20°C.
5. Water: 2 min.
6. Hypo Clearing Agent: 2 min at 20 ° C (20g sodium sulfit/l).
7. Water: 5 min (very important!).
8. RE-HALOGING BLEICHBAD (if SW development used): 3-5 Min bei 20 ° 100 (5g / l KaliumHexacyanoferrat (3), 10g / 50 Kaliumbromid).
9. Water: 1 min.
10. Second exposure (if re-halogenization used): 30-60 seconds (rotate the coil in the water glass under the fluorescent lamp).
11. Color development (ECN-2): 15-16 minutes at 24 ° C (or about 18 minutes 30 seconds at 21 ° C). Important: Always use fresh developers!
12. Water as a stop: 30-60 seconds.
13. Bleaching: 5-7 min at 20-24 ° C.
14. Water: 5 min.
15. Stabilizer: 1 min.
16. Dry.

Optimized workflow with direct ECN-2 development

1. Remjet Removal Bad: 2 min at 22-24 ° C (100g sodium carbonate/l). 5x rinsing to clear.
2. Color development (ECN-2): 15-16 minutes at 24 ° C (or about 18 minutes 30 seconds at 21 ° C). Important: Always use fresh developers!
3. Water as a stop: 30-60 seconds.
4. Bleaching: 5-7 min at 20-24 ° C.
5. Water: 5 min.
6. Stabilizer: 1 min.
7. Dry.

Color correction and filtering: perfect the look

The pictures show that an artificial light film such as the 5251 50T has a strong blue bush in daylight. This is because the film is designed for 3200K (tungsten light), but daylight is about 5500k.

Correction on the computer:

• Use the Color temperature controller (Kelvin) in your image editing software. Increase the Kelvin value to make the image “warmer” and neutralize the bluish stitch.
• Use the Color controller (tint / green-Magenta), to correct any green stitches (often in the case of fluorescent light).
• Use neutral shades of gray or color fields in the picture as reference points for white balance.
• Ideally work with RAW-Scans For maximum flexibility.

For future recordings (filter):

• Use one 85B-Filter (Orange) in daylight to reduce the color temperature from 5500k to 3200K. This requires an exposure correction of approx. 0.6 aperture levels.⁹
• There are special for fluorescent light FL-Filter.¹⁰

Security and disposal

The chemical processing of film harbors health and environmental risks. ECN-1 formulations were historically “very toxic”.⁷

• Personal protective equipment: Always wear nitrile or cotton gloves and ensure good ventilation.¹¹
• Disposal: All chemicals (except photoflo) must be treated as hazardous waste and disposed of in accordance with local regulations.⁸

Conclusion: The fascination of the vintage film

The development of 60 years old Kodak ECN-1 film is a demanding but extremely worthwhile experience. It requires precision, patience and willingness to experiment. The unique colors and aesthetics that can be got out of this historical material are incomparable and tell a very own story. At 360 Customs, we are enthusiastic about the possibilities that open up through these custom processes and encourage you to explore the limits of analog photography even.

Sources

[1] Kodak
[2] Eastmancolor
[3] Preserving Motion Picture Film
[4] Film Collection ID Guide
[5] ECN-1 Discussion
[6] Digital Object Identifier
[7] Kodak Push-Pull Processing
[8] ECN-1 Processing with Vision3 Stocks
[9] ECN-1 Processing Steps
[10] At Home ECN/ECN-1 Processing
[11] What is ECN-2 Film?
[12] Understanding ECN-2 Processing
[13] Cinestill Instructions PDF
[14] ECP/ECN Table
[15] Archives Preservation PDF
[16] Kodak Professional CIS E30 PDF
[17] Kodak E6 Single Use Kit PDF
[18] Color Temperature Chart
[19] Understanding Colour Temperature
[20] Color Temperature and White Balance
[21] Reddit ECN/ECN-1 Processing
[22] Film Grain and Pixelation
[23] Youtube Video
[24] Confused About Stand Development
[25] SMPTE Digital Library
[26] SMPTE Standards
[27] Filmcolors Timeline
[28] VISION3 Technical Data PDF
[29] Tank History
[30] 85B Color Conversion Filter
[31] FL-B Fluorescent Filter
[32] Photographic Developer
[33] Processing Kodak Motion Picture Films PDF
[34] Color Negative Process Errors
[35] How to Load Bulk Film
[36] Kodak Push-Pull Processing
[37] Adobe White Balance Guide