As some of you know, in addition to running this blog and shooting/directing my own films I also have worked extensively as a colorist. More so than anything else that I do day to day, color grading has helped to improve my understanding and approach to cinematography immensely – and one of the biggest lessons I’ve learned over the years is that you shouldn’t always protect your highlights.
What Do I Mean By Protecting The Highlights?
Essentially what I’m referring to is the practice of exposing your image for the highlights (or hotspots) in the frame to ensure nothing clips. In a scenario where you have an actor standing in front of a bright window, exposing for the highlights would mean that you bring your exposure down low enough that the window isn’t blown out at all. This technique has become extremely popular amongst filmmakers (especially those from a DSLR background), simply because blown highlights on certain cameras can look absolutely awful, and underexposing is one of the simplest ways to get around it. The only problem is that this approach can often yield results that are just as bad, if not worse than letting those hot spots clip.
In an ideal world, you want every shot that you capture to be perfectly exposed. You don’t want to crush your shadows too much (otherwise you will lose shadow detail), but at the same time you don’t want your highlights to clip unnecessarily either. Unfortunately though, unless you are shooting in an ultra flat lighting situation – chances are either the highlights or the shadows are going to clip. And more often than not (at least for daytime work) it’s the highlights.
Practically any daytime interior or exterior shot that you capture is going to have some bright highlights that may become overexposed. This may be a window, a reflection, a white wall or any other number objects or sources. Even night time shots will have hotspots, usually in the form of bright light sources such as lamps or street lights that are prone to clipping. These types of shots can be a challenge to work around, but there are certainly ways to deal with them and still achieve a nice image… That said, your best bet usually doesn’t involve underexposing your entire shot.
To illustrate this, take a look at these luma scopes below. The first is from a perfectly exposed daytime image:
And the second is from an underexposed daytime shot:
Unless you are going for a really moody scene, you typically don’t want a daytime exterior to read this way on your scopes. It’s helpful to understand how underexposure translates visually on scopes as you can use your cameras built exposure tools to ensure that your luminance values are in the right place.
Why Underexposing Doesn’t Work
As I mentioned above, I do a lot of color grading work and by far the most common issue I encounter are underexposed shots – usually as a result of overprotected highlights. Having to attempt to save this type of underexposed footage time and time again has made me realize that this is a very common issue amongst filmmakers, and certainly one that is worth being addressed here.
The reason why protecting your highlights is a bad idea is quite simple.. You are ignoring the most important parts of your image (and therefore not exposing them properly) so you can retain detail in an unimportant area of the frame. For example, a shot that is exposed to the left (so a desk lamp doesn’t clip) is naturally going to be underexposed across the board. A bright light source like a lamp should probably be the brightest thing in your frame (for a nighttime shot at least), and there is absolutely no reason why we need to see any detail in that lamp. Our eyes don’t even see that way… But by exposing for that lamp, now all of the important parts of the frame (most importantly the actor’s faces) are going to be way underexposed.
Here is a still from my film ‘Footsteps’ where the window is blown out. We made the choice not to expose for the window to ensure our actors faces still retained some detail:
The fundamental issue with underexposing your footage is that in order to be color corrected later, a lot of heavy grading needs to be done… And even then, the final result is never great. The last thing you want to do with most cameras is bring up the shadows and midtones too much or you will start to introduce a lot of noise into your image. Unfortunately though, when attempting to save underexposed footage you really have no other choice. In the end you wind up with a very grainy shot that needs to be heavily de-noised, and that can lead to some very mushy footage.
What You Should Be Doing
The good news is that you don’t need to be protecting your highlights so aggressively. Or at least not in the way that I have described above. There are a number of ways that you can capture a properly exposed image without having to risk underexposing your talent.
One option is to simply blow out your highlights. This method applies best to scenarios where the highlights are minimal, or where you would expect them to be blown – such as the desk lamp scenario. No one is going to care if a tiny light source in the back of your frame is blown out, and even the largest scale feature films have blown highlights in many shots. It doesn’t always matter. So use your discretion and ask yourself if the hotspots in your image are even problematic at all, or if you are just exposing for them out of habit.
The next option is to actually light your scene properly! There is no denying that there are times when blown highlights are an issue… Especially when the source of them is large. If you have a giant window behind your talent that is blowing out – chances are you are going to want to make some adjustments to improve your image. That said, the only way to achieve really great results in these types of situations is to control the light in your scene more strategically. This may involve pumping in a bunch of fill light on your talent (so you can stop down your exposure and still have light on the talent’s face), or it might even mean using some ND gels. I’ve written about this before on the blog, but ND gels can be your best friend on set when battling window light. If you don’t have enough lights to compensate for a blown out window, you could simply gel the windows from the outside and bring down the exposure at the source.
And with some cameras, you even have the option of exposing to the right (overexposing) and then bringing down the highlights in post. You need to be careful with this technique as it really only works well with certain cameras, but some more capable cinema cameras (such as the Blackmagic Cinema Camera) actually thrive when overexposed. In fact, most of the time when shooting on a BMCC I will intentionally overexpose the image and then recover the highlights in post. This typically yields the best image, since any noise or grain is virtually non-existent when the image is crushed down to a normal exposure. So if you need to shoot in situations where you have little or no control over your lighting, shooting on a RAW camera, or at least a camera that has a lot of range in the highlights will help you a lot.
Here is a before and after example of an overexposed BMCC shot that was brought down in post:
That’s about it for now! Hopefully this post has convinced some of you that protecting your highlights isn’t the most important thing when it comes to capturing beautiful images…