The digital filmmaking handbook

CHAPTER 15 COLOR CORRECTION

white. Note that this will change the contrast in your image, but altered con￾trast will probably be better than flat, solid highlights. And, your highlights

will now be legal for broadcast (Figure 15.10).

Remember to reactivate the clamping in your CODEC before you

continue.

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With a simple Curves adjustment, you can manually “roll off” bright spots

rather than clamping them.

FIGURE

15.10

Luma Clamping Troubles

If you are using a CODEC that clamps luminance, you face another problem

besides having your highlights reduced to flat blobs of white. Say you have

a 4-second clip and you need to crop the frame to a smaller size during the

last 2 seconds. The easiest way to do this would be to make a cut in the clip

at the 2-second mark, and then apply a crop filter to the second part of the

clip.

This cropping will cause your NLE to render new pixels for that clip,

which of course, will require recompression using your chosen CODEC.

Unfortunately, if your CODEC performs luma clamping, the second clip will

If your project will eventually be transferred to film, color correction in the

computer will be a bit of a problem. If you’ve ever tried to print images on a

color printer, you’ve probably discovered that what’s on your screen doesn’t al

ways correspond to what comes out of your printer. The same is true for trans￾ferring images to film. The reasons for the disparity are many, and range from

differences in color gamut between video and film, to differences in transfer

processes, to differences in how the film is exposed during the transfer.

Professional editing and effects houses try to deal with this problem

through expensive, complicated procedures for calibrating monitors and other

digital equipment. In the end, such systems still give little assurance of what

the final color will look like. If your final destination is film and you want to

do a lot of color correction and color effects, it’s a good idea to talk to your film

transfer house. Tell them you’re concerned about color control and ask their

advice on how to proceed.

ONE MORE THING

Finally, we recommend color-correcting your footage before you composite

any other elements on top of it. Your composited layers may have color issues

of their own, so it’s better to separate the color troubles that your layers might

have. Once you’ve corrected each layer, you can composite them together and

then apply touch-up corrections to smooth the “seams” of your composites. If

you’re not sure what we mean about composites, don’t worry, a thorough dis￾cussion of compositing is coming up next.

Correcting Color

for Film

356 DIGITAL FILMMAKING HANDBOOK

now have very different luminance values than the first clip. Because the two

clips are butted against each other, this change in luminance will be very ob￾vious, and quite distracting.

What can you do? The best choice is to find a CODEC that lets you ren￾der unclamped video. If this is not an option (either due to cost or availabil￾ity), then you need to get the computer to re-render both clips (and possibly

your entire movie) so that every clip will be subject to the same clamping. If

you apply a 1-pixel crop to each clip, then the computer will be forced to re￾render everything. Because your video is overscanned, you’ll never see this

1-pixel loss.

CHAPTER

16Titling and

Simple

Compositing

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IN THIS CHAPTER

• Making Titles in Your NLE

• Compositing with Keys

• What Is an Alpha Channel?

• Compositing with Mattes

Compositing is one of the most powerful effects tools available to the

digital film-maker. You’ll use compositing techniques for everything

from repairing drop-outs, to creating video collages and special effects.

When we say “compositing,” we’re referring to the process of layering mul￾tiple images to create a final “composite” image. The layers can be QuickTime

movies or still images but, if you do your compositing work well, your audi￾ence will simply see a single, well-integrated shot. Your biggest concern when

compositing will be to craft the mechanisms of transparency that will allow one

image to be superimposed onto another. Once your composite is built, you’ll

need all of the color correction techniques we introduced in the last chapter to

blend the layers into a seamless, cohesive image.

The simplest, most common compositing task is the creation of titles and

credits. Every movie needs opening titles and a final credit roll, and some

movies—particularly documentaries—will probably need titles throughout.

The creation of titles marks the start of our compositing and special effects dis￾cussions, which will continue into Chapter 17.

Though your production may not need fancy special effects such as 3D-ren￾dered dinosaurs, or complicated composites and morphs, it probably will need

a title sequence at the beginning and a credit roll at the end. If you’re shoot

ing a documentary, you might also need to use titles to identify interviewees

and locations. Though your editing software probably includes some titling

functions, they might not be up to creating a cool, animated title sequence, or

even a simple list of rolling credits.

In this section we’ll cover the basics of titling and graphics and, along the

way, introduce most of the concepts that you’ll need to understand to pull off

the more complex, sophisticated effects that we’ll cover in the next chapter.

Titles and

Simple

Graphics

358 DIGITAL FILMMAKING HANDBOOK

CHAPTER 16 TILTING AND SIMPLE COMPOSITING

MAKING TITLES IN YOUR NLE

Most editing packages include titling functions that let you superimpose sim￾ple text titles over your images. Some packages include more advanced func￾tions such as rolls and animated text. Your editing package’s manual should

cover everything you need to know to use the built-in titler. But, no matter

what software you use, there are several things to keep in mind when building

your titles.

NOTE Note that it is absolutely essential that you have an NTSC monitor hooked up to

your system when you are creating titles! The only way to determine the legibil￾ity of your titles and graphics is to see them on an NTSC screen.

TIP Titles for Film Projects

If you’re finishing your project on film, the resolution of titles created in the in￾ternal title tool of your NLE will be too low for projection. You’ll need to create

high-resolution titles using Photoshop or After Effects and have them transfered

directly to film. You can also have titles created with an optical printer, which is

how all film titles were created until recently. The independent feature Boys

Don’t Cry used optical printing for their titles and effects.

Safe Titles

In Chapter 9, we discussed the action safe area of a shot. As you’ll recall, to

compensate for the possible differences between different television sets, a

video signal actually contains more picture than can be displayed. Your TV or

video monitor will crop off a good amount of this overscanned area.

Because it’s impossible to determine how much a particular TV or monitor

will overscan, some lowest-common-denominator averages have been deter￾mined. If you stay inside these averages, the odds are pretty good that your

video will not be cropped outside the edge of the monitor. The action safe area

is the larger of the two regions, while the title safe area is a little smaller. Keep

your titles within this area and they should be viewable on any screen.

Most titling functions allow you to display both action and title safe guides.

If your editing package doesn’t provide guides, then try to avoid placing text in

the outer 5% or so of your screen (Figure 16.1).

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