Improve Exposures Using Gradients

[ This article was first published in the April, 2004, issue of
Larry’s Monthly Final Cut Studio Newsletter. Click here to subscribe. ]

OK. I confess. I love taking pictures of trains. In my spare time, I wander around the California coast taking train pictures. However, when I looked at my MiniDV video of trains, I realized that, well, they didn’t look as good as I thought they should.

So, here’s a technique that you can use to improve the look of your exterior shots. (As an added bonus, this works as well in PhotoShop on stills as it does in video.) However, it requires using a feature of Final Cut that few people understand — composite modes.

There isn’t enough time to explain composite modes fully. Suffice it to say that composite modes use the underlying numbers that describe each image, rather than the image itself, to modify images using certain rules.

Here are two ways composite modes can improve your exterior shots.

Here’s a shot of an Amtrak train passing through a fog-shrouded valley at about 6:00 AM. It isn’t bad, but the sky is too bright and distracts from the train.

So, I placed the train into my timeline, then went to the Generators menu (red circle) and selected Render -> Gradient.

Clicking the Control tab at the top of the Viewer, I changed the orientation of the Gradient to be from Bottom to Top.

My gradient now looked like this.

Place the Playhead in the middle of the clip. Then, drag the gradient over to the Canvas window and select “Superimpose” from the pop-up overlay.

Select the gradient on the Timeline and go to Modify -> Composite Mode -> Overlay.

Notice how the sky got a bit darker and less dominant. The foreground lightened and the train took its rightful place as the principal object in the picture.

Using a gradient with an Overlay composite mode will darken the top half of a picture, while making the colors richer, and lighten the bottom of the shot.

All very cool.

So, feeling very confident, I selected another seriously back-lit shot. (One of the problems with shooting trains at sunset along the California coast is that, unless I want to go swimming, everything is back-lit. Now, I could shoot in the morning, but that is just plain too early to get up.)

Let’s see if our new technique can improve this picture.

Sigh… Disaster. Whacked-out colors in the sky. The foreground is too light and the train is still too dark to see.

But, all is not lost. Let’s try the same concept, but take it to the next level.

This time, we’ll create a Custom Gradient.

The differences are, among others, that we can adjust the angle of the gradient, the width of its edge and where the transition occurs.

Here’s what our gradient looks like after I finished tweaking.

Again, superimpose it over the train shot in the timeline. But this time, instead of selecting “Overlay” as the composite mode, let’s select “Soft light.”

Sha-zam! We can see the train, while still darkening the sky and not blowing out the foreground.

What’s the moral here? Several things:

1. Don’t be afraid to experiment with gradients and composite modes.
2. No composite mode works perfectly for all shots.
3. You don’t need to be stuck with a bad exposure, Final Cut gives you the tools you need to improve your shots.

All very cool.