How To Save Time In Post By Shooting Charts
As I prep for the grade of "The Kid," a short film I shot for Jeff Winograd on the 5D MKIII in RAW, I'm reminded about the importance of shooting charts during production. While I wouldn't say that you have to shoot charts during production, I will say that if you take that extra minute on set to shoot a chart, you will save considerable time in post, and make the grading process easier on yourself.
If you want to spend less time grading, and have more confidence as you grade, here is what I recommend doing...
In An Ideal Situation
The first thing you have to do is get ahold of a chart. Any chart that has a set standard of colors that you can reference later in post is better than no chart at all. However, I strongly recommend getting the DSC One Shot Chart. This chart is simple to use, doesn't take up a lot of space in your bag, and is reasonably priced. While you can use a Macbeth Chart, the DSC chart corresponds to actual vectors on the Vectorscope, which makes it easier to use. (Kodak also offers their own chart).
Now that you have your chart, it should be shot in the key light at the start of every major setup. As long as I am talking about the ideal situation, this chart will be shot at the head of every clip along with the slate, or in a short clip before the scene is slated. And, if you are using any camera filtration, you will want to shoot it with the filtration in place, and without the filtration. That way you will always that the chart referenced in the footage, which is especially helpful if the key light is constantly changing in color temperature - like when you shoot outside. However, we do not live in, or work in the ideal world where we have this kind of time to make the ideal happen ...
In A Less Than Ideal Situation
If you are like me, in the real world I find that there are times when I do not have the crew or time to shoot a chart with and without filtration for every setup. So, compromises have to be made. The first compromise I'll make is to shoot the chart, with and without filtration, once in the key light, and then only shoot it again when the key light changes in color temperature, or we move on to another scene.
If time or crew does not permit my first option, then I'll set up the chart in a controlled environment (black/dark room) and shoot it clean, and with all of the various flavors of filter combinations and key light temperatures, and various camera profiles (if those change at all). This typically only takes about 15 minutes. And this is what I did for the short, "The Kid," due to our limited resources.
What to Do In Post
Now that you have your chart shot, it is time to bring it into your grading application of choice to balance the image. Art Adams shows you how to do this with the DSC Chart here. What I typically do is to start with the clean version of the chart and balance that one first. After I have it balanced, I end up neutralizing any color shifts that are introduced by the camera itself. This is a MUST if you are shooting on the 5D using the Magic Lantern RAW hack, as a strong magenta cast is added to the RAW files, making for ugly images - or at least that was the case with the camera and firmware I was using ...
|Chart With Color Cast|
(Filtration: Tobacco 1 & 1/2 Hollywood Black Magic)
|Chart Without Color Cast - How It Should Look|
(Filtration: Tobacco 1 & 1/2 Hollywood Black Magic)
Now that I know that I have an image that is properly balanced, I will save that grade/setting, and apply it to all of the other charts that I have shot. By applying this grade to the filtered charts, I can now see what each image should look like with the camera filters applied. By comparing these charts to the clean chart, I can also have a standard to reference if I need to dial out or further enhance the filtered images in the grade (maybe the image is just a touch too orange, for example).
When it comes time to grade the final edit, I use the properly balanced grade that I saved as my baseline to start from. I've found this to be a great time saver, as a simple copy and paste quickly gives me a neutral starting place to begin my work. I do not have to worry about neutralizing any color cast that the camera may be unintentionally adding to every clip. I do this in Resolve by applying the correction in the first serial node, and then creating a new node to begin my grading.
|What the start of my node tree looks like in Resolve|
If you are using charts that have been shot using the second option I outlined in the Less Than Ideal Situation, then I recommend only using them to balance out any color casts in the image, as it is more than likely that the light levels of the key light will change from shot to shot, which means that setting your white and black points on the clean chart will not correlate to the light levels of your images in the edit. Fortunately, that is not the case for the color cast- that still remains, and is easy to dial out.
By taking the extra couple of minutes to shoot a chart during production (best option), or by taking a couple of minutes at the end of the shoot to film it, you will be speeding up your time in the grade. With a quick copy and paste you can apply the balanced correction and then get to the creative, and more fun part of the grade- enhancing the look to the footage.
Are you shooting charts on your productions? Have you found them to be helpful when it comes time for the grade? If you do not shoot charts in your production, how/why have you found that to be beneficial?
Until Next Time - Get Out There And Shoot!
Ryan E. Walters, Cinematographer