AshigrainColour screen reversal · Experimental
Dufaycolor
Additive colour through a visible red-green-blue mosaic.
Muted 1930s documentary colour seen through a visible red-green-blue mosaic. A model inspired by the additive screen process, not a reproduction. Original vs Ashigrain.
At a glance
- Exposure index
- 50
- Daylight
- Introduced
- 1930s
- Discontinued
- Process
- black-and-white reversal to a high-contrast monochrome transparency
- Prints on
- Reversal, viewed directly
About the film
Louis Dufay devised the mosaic colour screen behind Dufaycolor for still photography in 1908.
The film itself appeared in the 1930s from Dufaycolor Ltd., later Dufay-Chromex, and the Timeline of Historical Film Colors credits Dufay together with Thomas Thorne Baker and Charles Bonamico. Its base carried a réseau of red lines and alternating green and blue squares, separated by a varnish layer from a single panchromatic emulsion, and the film was loaded with the base towards the lens. After exposure it was reversed to a positive and viewed in daylight through the same mosaic. Because it ran in ordinary black-and-white cameras, it was a cheaper alternative to Technicolor, made in 35 mm and 16 mm and used for documentaries, experimental films and home movies. Its filters absorbed up to 80 % of the light, so it needed strong light and gave muted colours, and printing from negatives caused moiré. The films the Timeline lists run from Hans Richter's Wir leben in einer neuen Zeit! (1938) to Giorgio Ferroni's L'ebbrezza del cielo (1940). It came late among the additive screen processes but was among the most refined and best documented, and it was produced until the late 1950s.
Sources for this history
- Understanding colors of Dufaycolor: Can we recover them using historical colorimetric and spectral data? (arXiv:2501.06216), Jan Hubička, Linda Kimrová, Melichar Konečný
- Dufaycolor, Timeline of Historical Film Colors
The look
Dufaycolor was an additive colour-screen film of the 1930s to 1950s: one panchromatic emulsion behind a fine mosaic of red lines and green and blue squares. Ashigrain's version is a labelled surrogate, a model inspired by the process rather than a reproduction, and the mosaic stays visible in the image.
Best for
- Muted 1930s documentary looks
- Home-movie and amateur colour pastiche
- Textured, screen-patterned art films
Compare camera films
FilmSpeedGrain, RMS σD · lower means finer grainYears made
Ansco Color Negative 843Ansco Color Negative 843−1⅔ stops vs Dufaycolor · grain finerEI 16−1⅔ stops.0041951
Gevacolor Negative T 6.51Gevacolor Negative T 6.51−1⅔ stops vs Dufaycolor · grain finerEI 16−1⅔ stops.0071951
Technicolor Process IITechnicolor Process II−1⅔ stops vs Dufaycolor · grain coarserEI 16−1⅔ stops.0191922
Trucolor (two-colour)Trucolor (two-colour)−1⅔ stops vs Dufaycolor · grain coarserEI 16−1⅔ stops.0191945
Kodak Aerochrome III 1443Kodak Aerochrome III 1443−⅓ stop vs Dufaycolor · grain coarserEI 40−⅓ stop.0292001
Kodak Vision3 50DKodak Vision3 50DMade since 2011, in production · same speed vs Dufaycolor · grain finerEI 50same speed.0042011–
Fujifilm Velvia 50Fujifilm Velvia 50Made since 2007, in production · same speed vs Dufaycolor · grain finerEI 50same speed.0112007–
Agfa Agfacolor Ultra 50Agfa Agfacolor Ultra 50same speed vs Dufaycolor · grain finerEI 50same speed.0041995
Agfa Agfachrome RSX II 50Agfa Agfachrome RSX II 50same speed vs Dufaycolor · grain finerEI 50same speed.0111998
Fujifilm Fujichrome 64T Type IIFujifilm Fujichrome 64T Type II+⅓ stop vs Dufaycolor · grain coarserEI 64+⅓ stop.0132002
Kodak Kodachrome 64Kodak Kodachrome 64Made 1974–2009 · +⅓ stop vs Dufaycolor · grain coarserEI 64+⅓ stop.0161974–2009
Ilford Ortho PlusIlford Ortho PlusMade since 1997, in production · +⅔ stop vs Dufaycolor · grain coarserEI 80+⅔ stop.0131997–
Kodak Ektar 100Kodak Ektar 100Made since 2008, in production · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0052008–
Kodak Ektachrome 100DKodak Ektachrome 100DMade since 2018, in production · +1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0132018–
Ferrania Solaris FG Plus 100Ferrania Solaris FG Plus 100+1 stop vs Dufaycolor · grain finerEI 100+1 stop.0052002
Fujifilm Astia 100FFujifilm Astia 100FMade 2003–2012 · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0112003–12
Fujifilm Velvia 100Fujifilm Velvia 100Made since 2003, in production · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0112003–
Kodak Ektachrome E100SKodak Ektachrome E100S+1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0151996
Agfa Agfacolor Optima II 100Agfa Agfacolor Optima II 100+1 stop vs Dufaycolor · grain finerEI 100+1 stop.0051998
Agfa Agfachrome RSX II 100Agfa Agfachrome RSX II 100+1 stop vs Dufaycolor · grain finerEI 100+1 stop.0111998
Kodak Ektachrome E100VSKodak Ektachrome E100VS+1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0171998
Fujifilm Provia 100FFujifilm Provia 100FMade since 2000, in production · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0102000–
Kodak Ektachrome 100 Plus (EPP)Kodak Ektachrome 100 Plus (EPP)+1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0181988
Fujifilm FP-100CFujifilm FP-100CMade 1992–2016 · +1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0221992–2016
Lomography Redscale XR 50-200Lomography Redscale XR 50-200+1 stop vs Dufaycolor · grain finerEI 100+1 stop.0052025
Fomapan R 100Fomapan R 100Made since 1980, in production · +1 stop vs Dufaycolor · grain coarserEI 100+1 stop.0211980–
Kodak T-Max 100Kodak T-Max 100Made since 1986, in production · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0081986–
Ilford Delta 100Ilford Delta 100Made since 1992, in production · +1 stop vs Dufaycolor · grain finerEI 100+1 stop.0071992–
Fomapan 100 ClassicFomapan 100 ClassicMade since 2016, in production · +1 stop vs Dufaycolor · grain the sameEI 100+1 stop.0122016–
Eastman Color Negative 5247Eastman Color Negative 5247+1⅓ stops vs Dufaycolor · grain finerEI 125+1⅓ stops.0051983
Kodak Portra 160Kodak Portra 160Made since 2011, in production · +1⅔ stops vs Dufaycolor · grain finerEI 160+1⅔ stops.0062011–
Agfa Agfacolor Portrait XPS 160Agfa Agfacolor Portrait XPS 160+1⅔ stops vs Dufaycolor · grain finerEI 160+1⅔ stops.0061995
Kodak Vision3 200TKodak Vision3 200TMade since 2010, in production · +2 stops vs Dufaycolor · grain finerEI 200+2 stops.0062010–
Kodak Verita 200DKodak Verita 200DMade since 2026, in production · +2 stops vs Dufaycolor · grain finerEI 200+2 stops.0062026–
Kodak Gold 200Kodak Gold 200Made since 2007, in production · +2 stops vs Dufaycolor · grain finerEI 200+2 stops.0082007–
Ferrania Solaris FG Plus 200Ferrania Solaris FG Plus 200+2 stops vs Dufaycolor · grain finerEI 200+2 stops.0052002
Kodak Ektachrome E200Kodak Ektachrome E200+2 stops vs Dufaycolor · grain coarserEI 200+2 stops.0181997
Agfa Agfachrome RSX II 200Agfa Agfachrome RSX II 200+2 stops vs Dufaycolor · grain coarserEI 200+2 stops.0141998
Kodak Kodachrome 200Kodak Kodachrome 200+2 stops vs Dufaycolor · grain coarserEI 200+2 stops.0271986
Kodak Tri-X Reversal 7266Kodak Tri-X Reversal 7266Made since 2003, in production · +2 stops vs Dufaycolor · grain coarserEI 200+2 stops.0242003–
Kodak Vision3 250DKodak Vision3 250DMade since 2009, in production · +2⅓ stops vs Dufaycolor · grain finerEI 250+2⅓ stops.0062009–
Fujifilm Eterna 250DFujifilm Eterna 250DMade 2005–2013 · +2⅓ stops vs Dufaycolor · grain finerEI 250+2⅓ stops.0052005–13
Kodak Vision 250DKodak Vision 250DMade 1997–2005 · +2⅓ stops vs Dufaycolor · grain finerEI 250+2⅓ stops.0071997–2005
Kodak Aerocolor IV 2460Kodak Aerocolor IV 2460Made since 2009, in production · +2⅓ stops vs Dufaycolor · grain coarserEI 250+2⅓ stops.0132009–
Eastman Double-X 5222Eastman Double-X 5222Made since 1960, in production · +2⅓ stops vs Dufaycolor · grain coarserEI 250+2⅓ stops.0131960–
Kodak Portra 400Kodak Portra 400Made since 2010, in production · +3 stops vs Dufaycolor · grain finerEI 400+3 stops.0072010–
Fujifilm Provia 400FFujifilm Provia 400F+3 stops vs Dufaycolor · grain coarserEI 400+3 stops.0172000
Ferrania Solaris FG Plus 400Ferrania Solaris FG Plus 400+3 stops vs Dufaycolor · grain finerEI 400+3 stops.0062004
Fujifilm Pro 400HFujifilm Pro 400HMade 2004–2021 · +3 stops vs Dufaycolor · grain finerEI 400+3 stops.0052004–21
Kodak Ektachrome 400XKodak Ektachrome 400X+3 stops vs Dufaycolor · grain coarserEI 400+3 stops.0371992
Fujifilm Superia X-TRA 400Fujifilm Superia X-TRA 400+3 stops vs Dufaycolor · grain finerEI 400+3 stops.0052006
LomoChrome Color '92 Sun-kissedLomoChrome Color '92 Sun-kissed+3 stops vs Dufaycolor · grain finerEI 400+3 stops.0052024
Kodak Tri-X 400Kodak Tri-X 400Made since 1954, in production · +3 stops vs Dufaycolor · grain coarserEI 400+3 stops.0171954–
Kodak T-Max 400Kodak T-Max 400Made since 2007, in production · +3 stops vs Dufaycolor · grain finerEI 400+3 stops.0102007–
Ilford HP5 PlusIlford HP5 PlusMade since 1989, in production · +3 stops vs Dufaycolor · grain coarserEI 400+3 stops.0161989–
Ilford Delta 400Ilford Delta 400Made since 2002, in production · +3 stops vs Dufaycolor · grain finerEI 400+3 stops.0102002–
Kodak Vision3 500TKodak Vision3 500TMade since 2007, in production · +3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0072007–
Fujifilm Eterna Vivid 500Fujifilm Eterna Vivid 500Made 2009–2013 · +3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0052009–13
Fujicolor Reala 500DFujicolor Reala 500D+3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0052001
Kodak Vision2 Expression 500TKodak Vision2 Expression 500T+3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0092003
Fujifilm Eterna 500Fujifilm Eterna 500Made 2004–2013 · +3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0052004–13
Eastman EXR 500TEastman EXR 500TMade 1989–1995 · +3⅓ stops vs Dufaycolor · grain finerEI 500+3⅓ stops.0081989–95
Kodak Portra 800Kodak Portra 800Made since 2000, in production · +4 stops vs Dufaycolor · grain finerEI 800+4 stops.0092000–
Ferrania Solaris FG Plus 800Ferrania Solaris FG Plus 800+4 stops vs Dufaycolor · grain finerEI 800+4 stops.0072004
Konica Centuria Super 1600Konica Centuria Super 1600+5 stops vs Dufaycolor · grain finerEI 1600+5 stops.0072002
Kodak Ektachrome P1600Kodak Ektachrome P1600+5 stops vs Dufaycolor · grain coarserEI 1600+5 stops.0501999
Kodak T-Max P3200Kodak T-Max P3200Made since 1988, in production · +6 stops vs Dufaycolor · grain coarserEI 3200+6 stops.0181988–
Ilford Delta 3200Ilford Delta 3200Made since 1998, in production · +6 stops vs Dufaycolor · grain coarserEI 3200+6 stops.0191998–
Science & sources
A model inspired by the additive screen process, not a reproduction of Dufaycolor. No sensitometric data of the film exists, so its silver record is borrowed from Kodak Tri-X Reversal 7266, with that film's curve, sensitivity and MTF, and its grain from Kodak Double-X 5222, while the mosaic's geometry and colours follow published measurements.
Response curves and the evidence behind the model
Compare manufacturer data with Ashigrain’s response on the same axes. These curves show how the model is calibrated to its sources; they do not establish a match to photographed film.
Characteristic response
RMS granularity
Density variation (σD). Where the datasheet gives a single grain value, the response away from that point is an approximation.
| Channel | Density | Datasheet-based σD | Model σD |
|---|---|---|---|
| R | 0.3 | 0.009426 | 0.009293 |
| G | 0.3 | 0.009426 | 0.00926 |
| B | 0.3 | 0.009426 | 0.009267 |
| R | 0.6 | 0.010914 | 0.01076 |
| G | 0.6 | 0.010914 | 0.010722 |
| B | 0.6 | 0.010914 | 0.01073 |
| R | 1 | 0.012308 | 0.012135 |
| G | 1 | 0.012308 | 0.012091 |
| B | 1 | 0.012308 | 0.012101 |
| R | 1.5 | 0.012607 | 0.012429 |
| G | 1.5 | 0.012607 | 0.012385 |
| B | 1.5 | 0.012607 | 0.012395 |
| R | 2 | 0.013571 | 0.01338 |
| G | 2 | 0.013571 | 0.013332 |
| B | 2 | 0.013571 | 0.013343 |
Model limits
These images show the film model in use. Spectral response, lighting and viewing conditions include approximations. Halation, bloom, grain size, weave and flicker are not fully measured for each film. The look of real film also depends on development and print timing.
- This is a model inspired by the Dufaycolor screen process, rather than a reproduction of the original film.
- No characteristic curve, spectral sensitivity, MTF or grain measurement of Dufaycolor exists in the sources. The silver record is the named proxy Kodak Tri-X Reversal 7266, with its curve, panchromatic sensitivity and MTF, and grain is proxied from Kodak Double-X 5222.
- The réseau is drawn as a visible mosaic of red lines and green and blue squares at 20 lines per millimetre, within the published range; its angle and element areas are estimates.
- The element colours are period spectra corrected to the published colorimetry. How projection blurred and mixed the mosaic, and how a display pixel samples it, are approximated.
- The proxy's sensitivity is printed only to 640 nm, so the red elements record light from 590 to 640 nm only.
- The exposure index of 50 is an assumption: the proxy's EI 200 reduced by the screen's light loss.
- Under custom lights the fast rendering path follows the full spectral calculation less closely for this film than for most others.
- Custom lighting spectra, camera metering and the spectral reflectance inferred from fixed-white-balance footage are assumptions used by the model, not measurements of this film.
- Push and pull have no published curves for this film and use a generic model.
- Characteristic response outside the published exposure range is an extrapolation, not measured film data.
- The available sources do not measure veiling flare during projection. The model approximates its contribution to lifted blacks on screen, so the result is not a measured projection contrast.
Reciprocity: not modelled. Exposure time has no effect on this film.
Film guide: assumptions and practical choices
Sources
- Process: J. Hubicka, L. Kimrova, M. Konecny: Understanding colors of Dufaycolor: Can we recover them using historical colorimetric and spectral data? (arXiv:2501.06216v1), arXiv 2501.06216v1, submitted 2025-01-05 (9 pp), p. 2
- Characteristic curves: KODAK TRI-X Reversal Film 7266 Technical Data, H-1-7266t, Revised 7-15, p. 3