[This article was first published in the May, 2006, issue of
Larry's Final Cut Pro Newsletter. Click here to subscribe.]

Video is really, really good at showing motion and emotion. It's not so good at displaying text.

One of the discouraging facts of life is that we create all these great graphics on our computers only to see them destroyed when they get transfered to video. (Well, OK, maybe not destroyed, but really, really different.)

Is there anything we can do to change this situation? Well, um, no. But, there are things you can do to improve the look of your graphics and text when they are displayed on video. And that's what this technique is about.

First, I'll explain how video and computers are different, then wrap up with a series of specific suggestions you can use to improve the look of your text.

In the beginning

Video was invented about forty years before computers; which means that computers were able to improve on the lessons we learned during the development of video. Because of this, there are six major differences between graphics on video and graphics on the computer. Keeping these in mind will help you improve the look of your text.

These seven differences are:

• Video is fixed resolution, computer resolution varies
• Video displays interlaced images, computers display progressive images
• Video gamma is different from computer gamma
• Video white is grayer than computer white
• Video uses YCrCb colors, which are more restrictive than the computer's RGB colors
• Video colors are not as precise as computer colors
• Video pixels are rectangular, the computer's are square

Let's take a look at each of these and see what problems they cause.

Fixed Resolution

Regardless of the size of our video monitor, all SD video is 720 x 480 pixels (720 x 486 for you broadcast types and 720 x 576 for PAL). If you do the math, this works out to about 0.3 megapixels -- a far cry from even a cheap digital still camera's 4, 6 or 8 megapixels.

This limited number of pixels means that your image quality varies by screen size. The bigger the screen, the grainier the image. Also, because there are so few pixels, lines that are nearly horizontal or vertical will show serious "stair-stepping," in a way that the same line on the computer will not.

This means that, graphically, we need to avoid using very fine detail or lots of thin or swirly lines. Video just doesn't have enough pixels to draw the image accurately.

Interlacing

NTSC, PAL, and some HD formats are interlaced. This means that while we see many complete images each second, each image, or field, is not complete in and of itself. Instead, the video monitor displays the image in two parts -- first all the odd lines of the image, then all the even lines.

This means that in the US, we are not seeing 30 images per second, but, instead, are seeing 60 half-images per second. These "half-images" are called "fields." (PAL displays 25 images per second, composed of 50 half-images, or fields.) Essentially, interlacing means that the vertical resolution of our image is instantly cut in half, because we are only seeing 1/2 the image at any given instant.

The result of using fields is that we have even less image data to work with. Thin lines flicker wildly because they are in one field, and not the other. Curved lines look even more stair-stepped. A moving object has weird horizontal lines radiating out from each edge that you can see on the computer, but not on the video monitor.

FCP suppresses displaying interlace lines UNLESS you show your image at 100% size in either the Canvas or Viewer. This picture illustrates what interlacing looks like; the red arrow points to the horizontal interlace lines.

Video gamma is different from computer gamma

This was illustrated in a message from Joe Sphinx:

Hey Larry, this sounds like a stupid problem, but I'm having an FCP 5 problem. I captured hdcam material via decklink card in FCP 5 at dv resolution for offline. then wanted to export stills from the timeline as uncompressed tiffs with quicktime conversion. when having done this, pics come out darker than what is represented on timeline and external monitor. Any ideas around this?

Larry replies: Yup. The computer does not display the same color levels as video. Each use a different gamma (or mid-tone gray) setting. The standard gamma for the Mac is 1.8. The standard gamma for video is 2.2, which is darker than 1.8. You can compensate by load your stills into PhotoShop and setting the mid-tone gray setting in Levels to 1.2. However, don't change the gamma setting on stills you want to reimport into your FCP project, or they won't match your existing footage.

TV White is Actually Gray

Video was invented in an analog world -- computers are digital. Consequently, they don't use the same black and white points.

Digital black is displayed at 0% on FCP's Waveform monitor. Digital white is displayed at 109%. (Here's a good article on how to read scopes.)

However, digital black to white is too great a range for analog video, which include broadcast and DVD duplication. When you are creating graphics or text for video, set your black level to zero on the Waveform monitor, but keep your white level to 92% (235 in PhotoShop's color picker).

This is called keeping your white levels "broadcast safe." You can clamp your white levels to the correct value by applying the Broadcast Safe filter (Effects > Video Filters > Color Correction > Broadcast Safe).

You can tell if your white levels are too hot by selecting either the Canvas or the Viewer and choosing View > Range Check > Excess Luma. If you see a yellow warning triangle, your white levels are too hot. A green check-mark means they are OK.

You can see this, as well, by looking at your video on the Waveform monitor. If any white pixels are above the 100% White line, your white levels are too hot.

Excess white levels will cause white text to shimmer, tear, or break-up. It can also cause a buzz in the audio. It also means that your video will be rejected for broadcast, as well as by most cable outlets and duplication facilities. You'll need to reduce your white levels and re-output.

Shooting, editing, and outputting on DV -- since that is all digital -- does not require clamping, or restricting, your white levels to 100%. However, if you then compress your file for DVD, you'll find that the process of compression converts your images into a broadcast safe format, which may, or may not, give you the results you expected.

Video can't display as many colors as your computer

Computers use an RGB color space, digital video uses YCrCb (analog video uses YUV). Both video color spaces are more restrictive than the computer. In other words, you can easily create colors on the computer that can't be displayed in video. Saturated yellows and blues come instantly to mind.

You can tell if your chroma levels are too hot by selecting either the Canvas or the Viewer and choosing View > Range Check > Excess Chroma. If you see a yellow warning triangle, your white levels are too hot. A green check-mark means they are OK. (These symbols look remarkably similar to the white level symbols I just discussed -- that's because they are.)

You can see this, as well, by looking at your video on the Vectorscope. If you connect the tops of the six targets, representing the six primary and secondary colors, if any white pixels exceed the boundaries of that rectangle, your chroma levels are too hot.

Excess chroma levels, like excess white levels, will cause colors to shimmer, tear, or break-up. It can also cause a buzz in the audio. It also means that your video will be rejected for broadcast, as well as by most cable outlets and duplication facilities. You'll need to reduce your white levels and re-output.

Video colors are not as precise as computer colors

Through a process called "color-sampling," the colors of adjacent video pixels are averaged to reduce file size. The problem with color sampling is that the quality of your image is often degraded. Worse, it gets harder to pull a clean chroma-key, or to do good color correction.

Here are two articles on my website that describe this problem in more detail:

• DV, Color Space and Chroma-keying, by Larry Jordan
• What is Color Sampling, by Graeme Nattress

The key issue with color sampling is that we don't have the same precision with color in video that we do with the computer. This is, generally, not an issue when we are shooting pictures, but becomes a significant concern when doing effects compositing, color correction, chroma-key, or adding text.

Video pixels are rectangles

Of all the problems between computers and video, this one causes the most confusion. While most High-Def video uses square pixels, NTSC and PAL do not. Both are rectangles, an NTSC pixel is tall and thin, while a PAL rectangle is short and fat.

This means that when we create graphics on our computer, we sometimes need to take this into account. I say sometimes because Final Cut is inconsistent in how it deals with imported graphics. Here's the scoop: if you are creating single layer graphics, such as scans or text supers, to import into FCP, you must adjust your image size for the difference between square and rectangular pixels. If you are creating multi-layer PhotoShop graphics, you don't.

Here's a table that will help you better plan your images. This assumes you want all images imported full-screen with no moves on the image. (These numbers came from Apple's web site.)

Sigh... It's enough to drive you completely nuts.

By the way, if you want to create an SD image for camera moves, a size that I recommend is 1800 x 1350 x 72. This works great for moves on scanned images.

HDV is a special case

Joe Ruscitto writes:

I would like to ask you some further questions concerning HDV. I still am somewhat confused, about still photographs that are going to be imported into an HDV project. What am I resizing these pictures to? Is it 1440x 1080 or is 1920 x 1080. These stills have been scanned at a high resolution so they do need to be resized for FCP. Are we also dealing with square and non-square pixels?

The other question concerns some if the footage was shot DV 16x9. Should I be capturing using the NTSC DV anamorphic codec. That is somewhat confusing to me. How will this cut together in the HDV sequence. The aspect ratio will still be 720 X480. Does this footage have to be scaled up to be compatible with the HDV footage in the sequence?

Larry replies: I TOLD you this was a mess!

• HDV uses square pixels. If you want to import an image into an HDV sequence, size it to 1920 x 1080 x 72
• To capture DV 16x9, select the ""DV NTSC - Anamorphic" Easy Setup in FCP 5
• To combine DV and HDV footage on the same timeline, you need to decide if you want to output HDV or DV. Whichever you decide, the other format will need to render before it will play back. Up-rezing DV footage to HDV will NOT make it look better.
  

Tips to Improve your Text

So, given all these constraints, it's a wonder we can create anything on our computers that displays properly on video. But, we can. And here are some tips that can help.

1. Avoid lines thinner than 4 pixels, they will flicker
2. Avoid lines that are almost horizontal or almost vertical, they will stair-step
3. Avoid fancy, curvy fonts like Harrington, Chancery, or Savoye
4. Avoid fonts with very thin bars or serifs, such as Engravers, Baskerville, or Modern
5. Avoid point sizes smaller than 24 points
6. Avoid saturated colors, use the Vectorscope if you are unsure
7. Avoid whites brighter than 92% (235 in PhotoShop)
8. Always use drop shadows on any text you want your viewers to read
9. Always keep any text you want viewers to read inside Title Safe
10. Keep text on screen long enough for you to read it three times.

Remember that text always looks better on your computer screen than it does on a TV set. So, if you can't read it inside Final Cut, your viewers won't be able to read it either.

Larry Jordan is a post-production consultant and an Apple-Certified Trainer in Digital Media with over 25 years experience as producer, director and editor with network, local and corporate credits. Based in Los Angeles, he's a member of both the Directors Guild of America and the Producers Guild of America.

Any references to trademarks or products are used for editorial purposes only. Text copyright 2006 by Larry Jordan and Associates, Inc.. All rights reserved.

Larry Jordan is a post-production consultant and an Apple-Certified Trainer in Digital Media with over 25 years experience as producer, director and editor with network, local and corporate credits. Based in Los Angeles, he's a member of both the Directors Guild of America and the Producers Guild of America.

The information in this article is believed to be accurate at the time of publication. However, the author assumes no liability in case things go wrong. Please use your best judgment in applying these suggestions.

The opinions expressed in this article are solely those of the author. This newsletter has not been reviewed or sanctioned by Apple or any other third party. All trademarks are the property of their respective owners and are mentioned here for editorial purposes only.

Links to my website home page or this article are welcome and don't require prior permission.