As some of you know, in addition to running this blog and shooting/directing my own films, I work extensively as a colorist. Color grading has helped improve my understanding and approach to film photography more than anything I do on a day-to-day basis – One of the most important lessons I’ve learned over the years is that you shouldn’t always protect your highlights.
What does it mean to protect highlights?
Essentially, I’m referring to the practice of exposing your image for the highlights (or hot spots) in the frame to ensure there’s no clipping. If the actor is standing in front of a bright window, exposing for highlights means lowering the exposure low enough so that the window doesn’t blow out at all. This technique has become very popular among filmmakers (especially those with a monocular background) because blown highlights look really bad on some cameras, and underexposing is one of the easiest ways to fix this problem one. The only problem is that this approach often produces results that are just as bad, or even worse, than letting those hotspots clip.
In an ideal world, you want every photo you take to be perfectly exposed. You don’t want to ruin the shadows too much (otherwise you’ll lose shadow detail), but at the same time you don’t want the highlights to be clipped unnecessarily. But unfortunately, unless you’re shooting in super-flat lighting situations, chances are good that the highlights or shadows will be clipped. Usually (at least for day jobs) this is the highlight.
Virtually any daytime indoor or outdoor photo you take will have some bright highlights that may be overexposed. This can be a window, a reflection, a white wall, or any other number of objects or sources. Even shooting at night can have hot spots, often in the form of bright light sources such as lamps or streetlights that are prone to clipping. These types of shots can be a challenge, but there are certainly ways to deal with them and still get a nice image… That said, your best options usually don’t involve underexposing the entire shot.
To illustrate this, take a look at these brightness ranges below. The first is from a perfectly exposed daytime image:
Second photo from underexposed daytime:
Unless you want to shoot a really moody scene, you generally don’t want daylight exteriors to read this way on your scope. It’s helpful to understand how underexposure translates visually on a scope, as you can use your camera’s built-in exposure tools to make sure the brightness values are in the right place.
Why underexposure doesn’t work
As I mentioned above, I do a lot of color grading work, and by far the most common problem I encounter is underexposed photos – usually caused by over-protecting highlights. Having to try and save this type of underexposed footage again and again made me realize that this is a very common problem among filmmakers, and certainly one worth addressing here.
The reason why protecting your highlights is a bad idea is simple. You’re ignoring the most important parts of the image (and therefore not exposing them correctly), so you preserve detail in unimportant areas of the frame. For example, a shot exposed to the left (so the desk lamp doesn’t clip) will naturally be underexposed across the board. A bright light source like a lamp should probably be the brightest thing in the frame (at least for night shots), and there’s absolutely no reason we need to see any detail in that light. Our eyes can’t even see something like that…but by exposing for the light, now all the important parts of the frame (most importantly the actor’s face) will be underexposed.
This is a still from my movie “Footsteps” with the windows blown out. We chose not to expose to the viewport to ensure that our actor’s face still retained some detail:
The fundamental problem with underexposed footage is that it requires a lot of grading in order to color correct it later… and even then, the end result is never very good. With most cameras, the last thing you want to do is crank up the shadows and midtones too much or you’ll start introducing a lot of noise into your image. But unfortunately, when trying to save underexposed footage, you really have no choice. You end up with a very grainy shot that requires a lot of denoising, which can lead to some very mushy footage.
what you should do
The good news is that you don’t need to be so aggressive about protecting your highlights. Or at least not in the way I described above. There are several ways you can capture correctly exposed images without risking underexposure.
One option is to simply highlight your highlights. This method works best for scenes with minimal highlights, or where you want the highlights to be blown out, such as a desk lamp scene. No one cares if a tiny light source behind the frame is exposed, and even the largest feature films will have bright spots in many shots. This isn’t always important. So think carefully and ask yourself if there’s something wrong with the hot spots in your image, or if you’re just exposing them out of habit.
The next option is to actually light your scene correctly! There’s no denying that sometimes blown highlights can be a problem…especially when they come from a large source. If you have a huge window exploding behind your talent – chances are you’ll want to make some adjustments to improve your image. That said, the only way to achieve truly great results in these types of situations is to control the light in your scene more strategically. This may involve injecting a beam of fill light into your actor (so you can stop the exposure and the light is still hitting the actor’s face), or it may even mean using some ND gel. I’ve blogged about this before, but when battling window light, ND gel can be your best friend on set. If there isn’t enough light to compensate for a blown window, you can simply gel the window from the outside and lower the exposure at the light source.
With some cameras, you can even choose to expose to the right (overexpose) and then lower the highlights in post-production. You need to be careful with this technique as it really only works with some cameras, but some more powerful cinema cameras (such as the Blackmagic Cinema Camera) actually work when overexposed. In fact, most of the time when shooting on the BMCC I will intentionally overexpose the image and then restore the highlights in post. This usually produces the best images, as there is virtually no noise or grain when the image is compressed to normal exposure. So if you need to shoot in a situation where you have little to no control over the lighting, shooting with a RAW camera, or at least a camera with a large highlight range, will help you a lot.
The following is a before-and-after example of an overexposed BMCC shot taken in post-production:
That’s it for now! Hopefully this article has convinced some of you that protecting highlights isn’t the most important thing when it comes to capturing beautiful images…
And don’t forget to check out the full range of color grading LUTs, film grain and post-production assets available here.
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