The Beginner‘s Guide to Understanding LUTs in Video Editing

If you‘re a video editor or aspiring filmmaker, you‘ve likely heard the term "LUT" thrown around quite a bit. But what exactly is a LUT, and how can you use them to enhance your video editing projects? In this in-depth guide, we‘ll break down everything you need to know about LUTs, from the technical definition to the different types and best practices for using them effectively. By the end, you‘ll have a solid grasp on this powerful color grading tool and be able to apply LUTs with confidence in your own work.

What is a LUT? A Technical Definition

First things first, let‘s define what a LUT actually is. LUT stands for "lookup table." In the context of video editing and color grading, a LUT is essentially a preset that maps one color space to another. Think of it like a mathematical formula that takes the color values of your video footage and transforms them according to predefined settings.

Technically speaking, a LUT is a table of numbers that specifies how to modify the RGB values of an image. It "looks up" the incoming color and luminance values and outputs transformed RGB values based on the desired color space or "look." LUTs can be 1D (one-dimensional) which affects the luminance only, or 3D which transforms the hue, saturation and luminance.

The Purpose and Benefits of Using LUTs

So why would you want to use a LUT in your video editing? There are a few key benefits:

1. Creative control: LUTs allow you to achieve a specific visual style or "look" for your video consistently and efficiently. Want to emulate the teal and orange color grading of blockbuster films? There‘s a LUT for that.
2. Color space conversion: LUTs are often used to convert raw footage from a camera‘s native color space (like log or RAW) into a standard viewing color space (like Rec. 709). This transforms flat-looking footage into a more dynamic, contrasty image.
3. Time savings: Applying a LUT to your footage is much faster than building a grade from scratch. You can also use LUTs to create a cohesive look across multiple clips or even an entire project.
4. On-set previewing: LUTs loaded into a camera or field monitor allow the crew to preview an approximation of the final grade while shooting. This helps the DP and gaffer make more informed lighting and exposure decisions on set.

Common Types of LUTs Used in Video Editing

Not all LUTs are created equal. Here are some of the most common types you‘ll encounter:

1. Conversion LUTs: These transform footage from one color space to another, like from log to Rec. 709 or from one camera‘s color space to another‘s. They don‘t apply a look per se, but prepare the footage for viewing or further grading.
2. Look LUTs: Often called creative LUTs, these apply a specific look or style to the footage, like emulating film stock or achieving popular color grades like the orange and teal look.
3. Viewing LUTs: These optimize footage to be viewed on specific display devices like a field monitor, projector, or TV. Viewing LUTs help ensure proper exposure and color representation on the final viewing device.

When to Use LUTs (And When Not To)

LUTs can be incredibly useful tools, but they‘re not always the best solution. Here are some best practices to keep in mind:

Use LUTs when:

• You need to convert footage from one color space to another
• You want to achieve a consistent look across multiple clips or projects
• You need to work quickly and efficiently
• You want to preview a look on set or in the field

Don‘t use LUTs when:

• You need precise, granular control over the grade
• The footage is low quality or has exposure issues that a LUT can‘t fix
• You‘re trying to match a specific reference that requires more nuanced adjustments
• You want to create a unique look that doesn‘t exist in preset LUT packs

Keep in mind that LUTs are meant to be a starting point, not the end of your color grading process. It‘s best to apply a LUT early in your editing workflow and then tweak and refine the grade as needed.

Debunking Myths: LUTs are Not Simply Filters

One common misconception about LUTs is that they‘re just fancy filters you can slap onto your footage willy-nilly. But LUTs are much more complex and purpose-driven than your average Instagram filter.

Remember, LUTs are mathematical formulas that transform the color and luminance values of an image in a very specific way. They‘re not arbitrary stylistic effects, but rather tools designed for specific technical purposes like color space conversions.

While creative look LUTs can be used to achieve a certain aesthetic, it‘s important to understand the intention behind the LUT and how it will affect your footage on a technical level. Haphazardly throwing look LUTs on your footage without regard for the original color space or exposure can do more harm than good.

How Pros Use LUTs: On-Set and in Post-Production

Professional cinematographers, colorists, and editors use LUTs in a variety of ways throughout the production process. Here are some common use cases:

1. On-set previewing: The DP or DIT (digital imaging technician) may create custom LUTs to preview the desired look of the footage on field monitors while shooting. This allows the crew to make lighting and exposure adjustments with the final grade in mind.
2. Dailies color grading: Colorists may apply conversion LUTs and look LUTs to quickly grade dailies for the director and producers to review.
3. Base grades: LUTs can be used as a starting point for the final color grade in the online editing stage. The colorist will apply the LUT and then refine the grade shot by shot.
4. Matching footage: LUTs can help match footage from different cameras or shot under different lighting conditions by converting them into the same color space.

Software That Supports LUT Workflows

Most major NLE (non-linear editing) software and color grading programs support LUT workflows. Some popular options include:

• DaVinci Resolve
• Adobe Premiere Pro
• Final Cut Pro X
• Avid Media Composer
• Blackmagic Fusion

These programs allow you to import, apply, and even generate your own LUTs. Many also support third-party LUT packs and allow you to organize your LUT library for easy access.

Mastering the Technical Side of LUTs

To get the most out of LUTs, it‘s important to have a solid grasp on some key technical concepts:

1. Color spaces: Understand the difference between camera raw, log, and Rec. 709 color spaces and how they relate to each other.
2. Bit depth: Ideally, you want to be working with 10-bit or higher footage to avoid banding and other artifacts when applying LUTs.
3. Order of operations: Be intentional about where you apply LUTs in your color grading pipeline. Generally, you want to apply conversion LUTs before creative look LUTs.
4. Monitoring: Make sure your display is properly calibrated and you‘re viewing the footage in the correct color space to ensure accuracy.

The more you dive into the technical side of LUTs and color grading, the more control and finesse you‘ll have over your image. Don‘t be afraid to experiment and test out different LUTs to find what works best for your specific footage and creative vision.

Final Thoughts and Key Takeaways

We covered a lot of ground in this guide, but here are the key takeaways to remember:

1. LUTs are mathematical formulas that transform color and luminance values in a specific way, not just arbitrary filters.
2. LUTs serve different purposes, from converting color spaces to applying creative looks.
3. Use LUTs intentionally and understand how they will affect your footage technically.
4. LUTs are just one tool in the colorist‘s toolbox – they‘re meant to be a starting point, not the end of the grading process.
5. Dive into the technical side of color grading to get the most out of LUTs and have more control over your image.

Armed with this knowledge, you‘re well on your way to mastering the art of LUTs in your video editing projects. Remember, practice makes perfect, so don‘t be afraid to experiment and find what works best for you. Happy grading!