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Digital restoration

Eye has more than 50,000 films stored in its depots - analog films on reels, in cans, in endless rows of shelving units. But nowadays most people watch films in digital form, and as a viewer, you assume that a digitized film is a faithful representation of the analog original. At the same time, viewers don't want too many traces of wear and tear, decay, or mold.
That's why we restore films.

How a film is restored has dramatically changed over the years. Restoration used to be a completely analog - photochemical - process. The original film was cleaned and then copied onto a new carrier. Ideally, a so-called wet gate was used for this. This device, which is still in use today, dips the film into a chemical solution, causing scratches and small damage to the film surface to be filled in and therefore less visible on the copy. After that, brightness and contrast could sometimes still be improved. An analog technique was even developed to restore faded colors of tinted films: the Desmet method.

The wet gate is still used, and the Desmet method is sometimes still used to restore color. However, with a severely damaged film, further analog options to restore the image are limited. In contrast, the digital toolbox is endless: anything is possible. You may have seen archival footage that looks suspiciously good: wait a minute... was that color in the original footage or was it added digitally?
At Eye, we are increasingly asked what we actually do when we restore a film - and what we don't do.

Being accountable

Archival films tell us something about the time in which they were made. Therefore, when restoring films, Eye does not strive for a spotless end result. When Eye restores a film, we say that we aim "to return the appearance of a film to a state closer to what it would have been when it was first created." Each restoration is different. We restore a silent film differently than a film noir from the 1940s or a color film from the 1970s. The silent film, in principle, retains some traces of dust, cables, and craquelure. With a newer film, we try to approximate how the film would have looked when it premiered.

Restoration guidelines and FIAF

We don't come up with our own restoration guidelines. The discussion about what film restoration entails has been going on for decades. Major film archives have joined forces in an international federation, the FIAF (International Federation of Film Archives). This organization has been dedicated to preserving and unlocking film heritage since 1938. It is the FIAF that sets restoration guidelines.

The FIAF guidelines for the restoration of films are strict: participating archives cannot simply call every digitally enhanced film a restoration. Affiliated archives distinguish between (among other things) a reproduction, a restoration, a reconstruction, and a derived work.

  • A reproduction is a copy: the aim is to create an "unmanipulated" representation that is as close as possible to the original material.
  • The term restoration is used to create a new rendering with the aim of reproducing as many features of the original, historical film as possible. Traces of damage can be removed, and sometimes several (incomplete) film copies are combined to arrive at a more complete end result.
  • A reconstruction is not just about putting together incomplete copies of the same film. It can also involve creating new material, but only with the aim of making the original film understandable: for example, an intertitle to explain that a scene is missing.
  • If a film contains additions or changes that are not related to the original film, we speak of a derivative work. Eye encourages the reuse of films in this way, but does not do this itself and therefore does not call these types of films restoration.

An example of such a film is Liquidator (Karel Doing, 2010), derived from Haarlem (Willy Mullens, 1922).

Film restoration step by step

But what do we do when we digitally restore a film? Although every restoration project is different, two things are the same with almost every restoration: the original film is preserved and a copy is made on film, the so-called analogue preservation - after all, digital media can also be vulnerable. Nowadays, that copy eventually ends up on a polyester carrier.
The film is first cleaned (ultrasonic) and then digitized in a special scanner with the aforementioned wet gate. Then the digital part begins.


With nitrate film, sometimes the frames are not precisely aligned on the film, resulting in a slightly jittery image. This is caused by a minimal play in the camera during recording. This image can be digitally stabilized, but we allow a small degree of movement because it is an inherent property that arose from the production process.

Dust removal

Traces of damage that are still visible after the wet gate are digitally removed. Eye uses software that compares different individual film frames to determine how the image should be completed. However, human control is still essential because the software is not always able to distinguish between a trace of damage and an element that belongs in the image.


Many silent films were recorded in black and white, but most underwent some form of colouring after recording before being shown in cinemas. Restoring colour involves restoring a colour that has faded or discoloured. It is not about adding a colour that was not part of the original production process.

Frame rate

When digitizing a silent film frame by frame, it looks different when played digitally compared to the analog original. This has to do with the frame rate: the number of frames per second at which the film plays. Most digital video formats play at 24 or 25 frames per second (fps). Silent films were often recorded at about 18 fps, but frame rates varying from12 to 22 fps also occur. Without intervention, digitized silent films are therefore systematically played too fast.

To play silent films digitally at the correct speed, some ingenuity is required. Essentially, extra frames need to be inserted to stretch a lower framerate to 24 fps. This can be done in various ways. There is software that can generate from a low frame rate 24 (or more) completely new frames. This makes every movement look super smooth, but a disadvantage of this method is that at the individual frame level, the film no longer contains any original image: each frame has been artificially created. Therefore, Eye chooses to duplicate some frames from the original film, for example, one in every three, to reach 24 fps, even though this produces a slightly less even result.


Silent films were shown with narration or music during the screening. Many cinemas had pianists or bands who drew from an existing repertoire of popular classical music to accompany various types of films as needed. Often there was no original score, and therefore the choice of music depended on the cinema musicians.

When showing a restoration, choosing the right music can be a challenge. Presenting a silent film without any music does not work, and most silent films were not intended to be screened in that way. But adding just any nostalgic music can make a film seem outdated. That is why new music is sometimes composed.

What Eye does not do is add background sound, or foley. (However, sometimes some foley is part of the new score or soundscape.) You perceive sound much less consciously than visual content, and we have been accustomed to having sound accompany everything for generations. Therefore many viewers would not notice if they hear street sounds in a market scene from 1919, and would simply assume that it was part of the original recording. But in 1919, there were no sound films.

Restoration of Oblomok imperii

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Restoration of Oblomok imperii (SUHH, Friedrich Ermler, 1929)

Limitless possibilities

This is in essence how a restoration at Eye works. But outside of the archival sector, there are also film enthusiasts who believe that an 'authentic' image quality does not do justice to the original film or filmmaker. If you can digitally polish a film in such a way that it looks like it was made yesterday, why wouldn't you?

They Shall Not Grow Old

An example that has received a lot of international attention is They Shall Not Grow Old (2018). This film about World War I was compiled by director Peter Jackson from archive footage from the British Imperial War Museum, to which he added audio consisting of interviews with soldiers. Jackson had the images coloured and added various layers of sound. The result is that as a viewer, you suddenly don't experience any distance to the past anymore: everything comes closer.

There are quite a few criticisms to be made of this project: there is no way to determine, for example, the original colours of the image. With every pink wall and blue cap, you wonder if that colour choice was primarily aesthetic. In addition, for maximum contrast, Jackson started the film with black-and-white images at their worst: played too fast and full of dust and scratches. This signals to the audience that black-and-white film, silent film, or old film in general is 'difficult' and not worth watching without maximum assistance.

However, the result was also very beautiful and was appreciated by a wide audience. At Eye, we were fascinated precisely because as a film archive, we have a different role from Jackson as a filmmaker. Not every 'archival' objection is an insurmountable obstacle for most viewers: as long as they know what they're getting into. Within the context of the film, that is made quite clear.

Knowing what you are looking at

But with a lot of archival footage you come across online, you have no idea what has actually been changed. Sometimes you see in the credits or description that the footage has been edited with artificial intelligence (or A.I.). Relatively old films are especially popular for these edits, as they have often fallen out of copyright.

As with film restoration, this involves software that compares different frames with each other, but goes much further: it can be used, among other things, to make the image appear sharper and to emphasize faces more. This cannot be seen separately from the wider use of visual technology in recent years, from facial recognition to deepfakes. An increasingly large part of the images we will encounter in the future will be more or less synthetically created. Archival film footage that is digitally available is not exempt from this development.


Film archives play an essential role because they safeguard the source material. Therefore, the original, analogue film is always preserved as it carries more authority than any duplicate or scan. We will continue to make these films available in a form that closely resembles the original. However, digital technology is constantly evolving, and film restoration moves along. Only time will tell what we will consider authentic in the future.