Collage of an eye consisting of color variations of the same image

ARRI Look File

Create your individual style!

What you see is what you get - with the freedom of Log C

In digital production one question is always present: “What will my image look like, when all the processing is done? Is it really what-you-see-is-what-you-get?” Yes, kind of! As described in our Log C section, all ARRI cameras record in Log C wide gamut color space. The camera image core (CIC) utilizes a look file to transform the flat, desaturated image into a pristine, color-rich image, followed by a color space transform either in-camera (ALEXA 35) or as part of the look file (all other ALEXA/AMIRA cameras).

This can happen in various ways. The most simple is using a conversion into HD or UHD color space (Rec 709 or Rec 2020 respectively). This is a straight, technical conversion. Some details in the highlights and blacks might be clipped by doing so:

When more advanced color grading or an individual live color grade is requested, the CIC and an ARRI Look File can be the anchor-point of color manipulation. The look file always alters colors “in log space” so as to have all color information to work with. A look can alter based on Color Decision List (CDL) values solely, or in addition to a full 3D LUT.

  • ARRI Look File 2

    ARRI Look File 2 (ALF2) is available for ALEXA Mini, AMIRA, ALEXA 65, ALEXA SXT, ALEXA LF, and ALEXA Mini LF.
    ALF2 also offers Video Look Parameters instead of a 3D LUT if required.

    ARRI cameras use the look file function to offer the option for on-set live grading through CDL manipulation (Color Decition List).

    Like other metadata, for example camera status information or lens metadata, the look file travels in each clip’s file header. This means if you have the original file, or a copy of it, you can extract the look file. Transcoding destroys all the embedded metadata. Looking at ALF2's role in a production shooting with ALEXA Mini for example, it plays a central role in the production’s camera department. ALF2 gives the director, cinematographer, and costume department a close idea about the final image:

  • ARRI Look File 4

    ARRI Look File 4 (ALF4) is only available in ALEXA 35 and requires log-to-log LUTs, where the color space conversion is being handled in-camera in CIC, or later in postproduction (again in CIC).

    ARRI cameras use the look file function to offer the option for on-set live grading through CDL manipulation (Color Decition List).

    For ALEXA 35 we removed a part of the look file to offer more flexibility on-set: ALEXA 35 can output SDR and HDR at the same time. Where ALF2 has the color space transform baked into the look file, ALF4 moves it into the camera to enable the output to different targets:

  • ARRI Look Library

    The ARRI Look Library is a collection of 87 looks that are available pre-installed in-camera. Due to their variety, the looks cater to a lot of different shooting scenarios.

    The looks are numbered within nine themed groups: Application, Black-and-White, Contrast, Environment, Film, Period, Season, Special, and Tinted. In a sense, the looks can be thought of as being similar to different film stocks, each providing a unique but repeatable aesthetic when combined with the cinematographer’s choice of lenses.

    The Look Library is a tool for on set as well as for postproduction: a look can be a grading node in a more complex setup or work on its own. When a look is selected on set it travels as metadata in the clip's file header into postproduction, where it can be extracted and exported as a 3D LUT. To ease the use in postproduction and the development of custom log-to-log look variants, we're also offering log-to-log versions of the Look Library free of charge.

    In general there are two Look Libraries: "LogC3" and "LogC4" - choose the right one depending on which camera was used on your project:

    • Look Library LogC3 for ALEXA Mini, AMIRA, ALEXA SXT, ALEXA 65, ALEXA LF and ALEXA Mini LF
    • Look Library LogC4 for ALEXA 35

    The looks are available as *.cube log-to-log 3D LUTs or as ARRI Look Files for in-camera use. See below.

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