Short answer
Colour timing is the photochemical way of setting a film's colour: a laboratory timer chooses three numbers for each shot, the red, green and blue printer lights, which set how much of each colour exposes the print. It changes overall density and colour balance and nothing else. The digital intermediate, from the late 1990s, replaced those three numbers with an image that could be altered in one hue range, one area or one object, and moved the work from the laboratory to a grading suite.
A print is made by shining light through the negative onto print stock. In an additive printer that light is split into red, green and blue, and each is set on a scale of points. One printer point is a fixed step of printing exposure, 0.025 in log terms, so twelve points double or halve the light. Kodak's note to timers gives the working rule that one stop of camera exposure corresponds to about seven points, because a negative's low contrast turns a stop into a smaller change of density, and uses equal points of 25 as the reference for a normally exposed grey card.
The numbers run the opposite way to intuition. A negative is being printed, so more light makes a darker print, and more red light makes a print that is more cyan.
With three lights a timer can make a shot lighter or darker and move its balance along any colour axis, and can change those settings from shot to shot by cueing the printer. That is all. Contrast, saturation and anything selective were out of reach: the whole frame received the same exposure. Contrast and saturation had to be set by other means, the stock, exposure, pushing, flashing, filtration and special processing such as silver retention. American Cinematographer's account of O Brother, Where Art Thou? records the limit directly: bleach-bypass tests were rejected because they could not be confined to the greens.
Kodak's handbook distinguishes one-light dailies, printed at the laboratory's standard light on the assumption that the negative is correctly exposed, from timed dailies, where an average light is chosen for each camera roll. Shot-by-shot timing came later, on the cut negative, in successive answer prints that the cinematographer and timer viewed and corrected until one was approved. The discipline this imposed was exposure on set. Gordon Willis used it deliberately on The Godfather, exposing so that the negative would print properly in one range only and could not be brightened afterwards.
Scanning the negative removed the whole-frame limit. Pleasantville, finished in 1998, had about 163,000 frames scanned so that colour could be removed from most of each image and kept in parts of it. O Brother moved its greens towards brown and yellow and left other hues alone. The Fellowship of the Ring planned digital grading from the outset and gave each location a scheme, desaturating the Mines of Moria entirely in the grade. Kodak's handbook, by 2007, describes scanning to a digital intermediate as the way many features were finished.
A graded image had to be recorded back to film for release, and the two did not always agree. Robert Richardson recalls that the three-strip emulation on The Aviator looked right in the suite and too grainy and soft on the first print. The vocabulary survived the change: the dailies of Killers of the Flower Moon were graded with printer-light adjustments only, beneath the show's lookup tables, in 2023. Photochemical finishing itself has not vanished either. Oppenheimer was released on film prints in three gauges, struck by the laboratory that processed its negative.
| Points | Log exposure | Exposure factor | Stops of printing exposure |
|---|---|---|---|
| 1 | 0.025 | ×1.06 | 0.08 |
| 2 | 0.050 | ×1.12 | 0.17 |
| 4 | 0.100 | ×1.26 | 0.33 |
| 7 | 0.175 | ×1.50 | 0.58 |
| 12 | 0.300 | ×2.00 | 1.00 |
| 25 | 0.625 | ×4.22 | 2.08 |
| Production | Route | What the record says |
|---|---|---|
| The Godfather (1972) | Colour negative, deliberately underexposed and push-processed; photochemical timing | Gordon Willis rated the colour negative faster than normal and had it pushed one stop, leaving it about half a stop underexposed. He said this left the laboratory one printing range and no room to change the look afterwards. |
| The Godfather (1972) | Colour negative, deliberately underexposed and push-processed; photochemical timing | The Sicilian exteriors were shot through heavy chocolate-brown filters, with lighter ones indoors to keep the relationship; the Hollywood scenes were given a brighter, harder, cleaner image. |
| Pleasantville (1998) | Colour negative; scanned at 2K; colour removed and restored digitally; film-out | The film was shot on colour negative. About 163,000 frames were scanned at 2K on a Philips Spirit DataCine at Cinesite, most of the colour was removed and some kept or changed with compositing software and in-house tools, and the result was recorded back to film on a laser recorder. |
| The Matrix (1999) | Colour negative; filtration, set colour and photochemical timing; some dye-transfer prints | Scenes inside the Matrix were given green by filters used selectively and by adding green in the timing. Scenes in the future world were lit bluer, with quarter blue gel on tungsten lamps, and kept very dark. |
| The Matrix (1999) | Colour negative; filtration, set colour and photochemical timing; some dye-transfer prints | A minority of the release prints, 150, were made by Technicolor's dye-transfer process; the rest were struck on ordinary print stock. |
| O Brother, Where Art Thou? (2000) | Colour negative; scanned at 2K; digital grade; film-out | The negative was scanned at 2K on a Spirit DataCine and graded digitally over about ten weeks before being recorded back to film. Photochemical tests, including bleach bypass, had been rejected because they could not be applied to one range of colours. |
| The Lord of the Rings: The Fellowship of the Ring (2001) | Super 35 colour negative; digitally graded throughout; film prints | Digital grading was planned from the outset. A facility was built for the production by Peter Doyle and PostHouse AG, with software written for it by ColorFront and later sold as 5D Colossus. The negative was Kodak and the prints Fuji. |
| The Aviator (2004) | Film origination; digital intermediate emulating two-colour and three-strip Technicolor | Robert Richardson worked with Technicolor Digital Intermediates and colourist Stephen Nakamura to emulate two-colour Technicolor for the first act and the saturated three-strip look for the second. |
| The Aviator (2004) | Film origination; digital intermediate emulating two-colour and three-strip Technicolor | Richardson says the three-strip emulation looked right in the grading suite and wrong on the first film print, too grainy and too soft, and had to be reworked. |
| Oppenheimer (2023) | 65 mm colour and black-and-white negative; photochemical prints | The film was shot on 65 mm colour negative, a daylight stock and a tungsten stock, and on a black-and-white negative that Kodak made in 65 mm for the first time for this production. FotoKem processed it. |
| Oppenheimer (2023) | 65 mm colour and black-and-white negative; photochemical prints | Film prints were struck for release: 30 in IMAX 70 mm, 113 in standard 70 mm and about 80 in 35 mm. |
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactStrong evidence
Kodak's guidance to film timers states that one stop of camera exposure corresponds to about seven printer points, and gives red, green and blue points of 25 each as the reference for a normally exposed 18 per cent grey card.
Source: Gray Card for the Film Timer
FactModerate evidence
A printer point is defined as 0.025 log exposure, one twelfth of a stop of printing exposure.
Caveat: The definition is from a reference work; Kodak's page confirms the consequence (about seven points per camera stop) but does not state the unit.
FactStrong evidence
Kodak distinguishes one-light dailies, printed at a standard or average light, from timed dailies, where a light is chosen for each camera roll, and describes printer-light changes being cued along the cut negative.
Source: The Essential Reference Guide for Filmmakers (Kodak publication H-845)
FactModerate evidence
On O Brother, Where Art Thou? photochemical tests including bleach bypass were rejected because they could not be applied selectively, and the negative was instead scanned and its greens altered digitally.
Colourwise analysisModerate evidence
Seven printer points multiply printing exposure by about 1.5, a little under 0.6 of a stop, which is the density change one stop of camera exposure produces on a low-contrast negative.
Based on: Calculated by Colourwise from 0.025 log exposure per point: 7 × 0.025 = 0.175, and ten to that power is 1.50.
Caveat: The seven-point rule is Kodak's approximation; the real figure depends on the stock's contrast.
Reviewed 6 October 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.