Color Correction for Video

Using Desktop Tools to Perfect Your Image

Steve Hullfish, Jaime Fowler

• Publisher: Routledge
• Year: 2013
• Print ISBN: 9781138459809
• eBook ISBN: 9781136059179
• Topic: Media & Performing Arts
• Subtopic: Film & Video

Use color to improve your storytelling, deliver critical emotional cues, and add impact to you videos. This book shows you how to analyze color correction problems and solve them- whatever NLE or plugin you use. Experienced editors and colorists in their own right, the authors also include the wisdom of top colorists, directors of photography, and color scientists to deliver this insightful and authoritative presentation of the theory and practice of color correction. The book provides technical insight into how to effectively color correct your video, also delving into how color can impact storytelling and deliver critical emotional cues. The new edition also includes 2 new "Quickstart Tutorials", a new chapter on how color impacts storytelling, information on the impact HD has had on the correcting process, and updated application specifications. The downloadable resources feature new and more robust tutorial media.

1

GETTING STARTED WITH COLOR CORRECTION

Quick Start

Nobody wants to wade through the entire text or a book before they feel they've learned anything, so this first chapter of the book is designed to get you started color correcting quickly. We'll gloss over a few important details in this chapter, but we'll cover those things in more depth in the remaining chapters. This chapter is an overview of the chapters to follow. The goal of this chapter is for you to make as much progress as quickly as possible.

The goal of this chapter is for you to make as much progress as quickly as possible.

The Goals of Color Correction

There are two primary objectives in basic color correction: spread your tonal range and balance the colors.

There are two primary objectives in basic color correction: spread your tonal range and balance the colors. There are a lot of other important goals, including matching shots from one to another, helping to tell the story, and making the images “pop” or “read.” But we'll focus on spreading the tonal range and balancing colors in this initial chapter.

Spreading the tonal range means that you take full advantage of the tonal range of your display medium. In most cases this means maximizing the number of levels of gray between the deepest black and the brightest white that your display or broadcast specifications can reproduce. For most people reading this book, that means a TV screen or maybe a computer display. It can also mean prepping the image for a digital intermediate transfer to film. Tonal range corrections do not always have to spread completely from 0% black to 100% white, but oftentimes they do. The other goal of tonal range corrections is determining if certain parts of the tonal range should be compressed while other parts should be expanded. We'll do a quick tutorial on this in a moment.

Tonal Range

Tonal range is sometimes also called the dynamic range, luminance range, or contrast range, though these terms can have slightly different technical definitions. The tonal range is the difference between the brightest and darkest areas of the image. The tonal range of the image—and how those tones are spread throughout the tonal range—defines its contrast. For some applications of this phrase, tonal range indicates the actual number of levels of tones that a recording medium can record (256 per channel in the case of RGB 8 bit, or 1025 per channel in the case of RGB 10 bit). For our purposes, we will refer to tonal range (singular) as the range of tones between brightest and darkest. Ansel Adams and other proponents of the Zone System break the tonal range of an image into 11 distinct tonal ranges.

Balancing the colors means that any unwanted color casts are eliminated. The reason for the term “balancing” will become more obvious as we start to examine and analyze our images with a number of different tools. Color casts in images are sometimes desired, for example, the warm, red tones of a sunset or the sad, blue, coolness of a rainy day. These are color casts that often serve the story, so we need to be careful not to eliminate them. Examples of color casts that are undesirable are usually caused by video cameras that haven't been white balanced properly or film footage shot with the wrong filter for the combination of film stock and light temperature.

Spreading the Tonal Range

Much of the information that viewers use to understand and interpret the image is based on the tonal range or contrast between brights and darks. In most cases we want to give viewers as much information as possible, but sometimes you don't, like the case of a thriller or horror movie where you may be trying to hide things in the shadows.

The first step in determining the proper tonal range where your image should “live” is setting the proper level for blacks or shadows.

The first step in determining the proper tonal range where your image should “live” is setting the proper level for blacks or shadows. Setting the black level is almost always the place where any experienced colorist starts a correction. So the question for a beginner is, “Where do I set the proper black level, and how do I know what I should set it to?”

This book is product and platform agnostic. In other words, this book is less about what buttons to push on specifc pieces of hardware or software and more about understanding the process so that you can feel comfortable color correcting on almost any application that exists now or in the future. Because of that, I'll show you the right buttons in a few applications. Hopefully you're using one of the apps that I used as an example. Otherwise, look for similar parameters in the software or hardware that you use.

Blacks are also known as shadows, pedestal, set-up, or lift, depending on the application.

Blacks are also known as shadows, pedestal, set-up, or lift, depending on the application. Setting the black level usually involves adjusting a slider called either “blacks,” “shadows,” “setup,” “lift,” or “pedestal,” such as the controls in the screen shots that are shown here from several of the most widely distributed applications with color correction capabilities.

Figure 1-1 FCP Color Corrector.

Figure 1-2 Color Primary room Basic tab.

Figure 1-3 Color finesse HSL Controls master tab.

Figure 1-4 Avid HSL Hue offsets tonal controls.

Figure 1-5 Premiere Luma Corrector.

Waveform Monitor

A waveform monitor displays the amplitude level— brightness and darkness— along the vertical axis with the dark parts of the image near the bottom and the brighter parts of the signal near the top. Technically, the horizontal axis of the waveform displays time, but practically speaking, the horizontal axis of the waveform corresponds to the horizontal placement of picture elements across the image with no regard to the vertical placement of elements in the image. The waveform monitor also displays chroma levels, but these are easier judged on a vectorscope.

How to Determine the Proper Black Level

When I started to learn color correction, the biggest mystery to me was simply “How do you know what's right?” To set black levels you need some tools for proper analysis of the black level. Basically that means a waveform monitor, though there are other tools that would work. We'll get into the full range of analytical tools later in the book. For now, a simple waveform monitor will do. Don't panic. You don't need to be an A/V geek or slide rule engineer to understand this display. We just need to know how low we can go legally, and that's pretty simple.

Firstly, you need to know what “legal black” is on your system or waveform monitor. For most waveform monitors, black is at 0 IRE or 0% or 0 millivolts. In the United States, which defnes black as 7.5 IRE for composite analog NTSC signals, black can mean 7.5 IRE or 0 IRE depending on the type of video signal. The easiest way to tell which is right for your system is to feed “filler” (the black signal your system generates whenever it doesn't have real video to send) to the waveform monitor.

The easiest way to tell which is right for your system is to feed “fller” (the black signal your system generates whene...

Table of contents

• Cover
• Color Correction For Video
• Full Title
• Copyright
• Contents
• Acknowledgements
• Introduction
• Chapter 1 Getting Started with Color Correction
• Chapter 2 Analyze This-Your Monitor
• Chapter 3 Using Scopes as Creative Tools
• Chapter 4 Other Methods to Analyze Footage
• Chapter 5 Colorists' Tools-Primary Color Correction
• Chapter 6 Secondary Color Correction
• Chapter 7 Tutorials
• Chapter 8 Advanced Color Correction Tutorials
• Chapter 9 The History and Role of the Colorist
• Chapter 10 Vision and Color Theory
• Chapter 11 Built-in Software and Plug-in Capabilities
• References
• Index