Properly Grade w/ Color Charts

what exactly is the purpose of a color chart and how can we use it to get better grades inside of DaVinci Resolve that's what I want to show you today because it's a simple premise once you understand how color charts work and how the color match feature Works inside a resolve but there's a couple of gotchas a couple plot twists that we want to watch out for so that we can make sure that we are actually taking best advantage of this feature inside of resolve so we're going to dive in right away but before we start looking at the color match feature itself in resolve I just want to get clear on what exactly color charts are for whether we're using the color match feature in resolve or for any other purpose why do we shoot color charts in the first place this is something that actually took me a little while to understand as a colorist here's what color charts are for let's take a look at the image that we have up right now by the way I've already got my color management set up and we are going to be working within a color management context today but if we take a look at this image I don't actually know what the original scene colors in this image should be I can see the way they're being reproduced right now and make some reasonable guesses about the color of my subject's wardrobe or the color of the background or the color of the foliage over here but I don't actually numerically know what those colors should be what they were in the scene on the day but because I have a color Checker in my frame I know or in this case resolve nose exactly what the color what the numerical value of this red patch should be or of these patches up here ought to be or of my grayscale steps down below these are internally stored numbers and what we can do with that information is compare what should this be against what it actually is what was captured what was encoded what are we showing to resolve right now and resolve can come up with a fit or a match and it can lessen that distance between what the patches should be and what the patch is actually are and in doing so the idea is that we are theoretically going to get a better balanced image we're going to get a more accurate reproduction of the scene colors this can be useful as a foundation when we begin our color grade that's what a color chart is for and I'm going to show you how to actually take advantage of the utility of a color chart here inside of resolve using the color match feature so I've gone down here to the color match palette down in the lower left hand corner and what I'm going to do now is grab my color chart mode here in the lower left hand corner of my viewer and I'm going to zoom out a little bit and let's go over to here and really all I'm going to do is fit this overlay so that each of the inner patches on the uh overlay are completely uh filled by their respective patch within the color chart now how do I know that this is a color Checker classic because I have different color charts that I can select from my drop down menu here well I know it's a color Checker classic because if I zoom in far enough I can see color Checker classic up in the upper left hand corner and color sector classic is one of the most common charts you're going to encounter when you're using the color match feature inside of resolve or just in general it's one of the more popular charts that's used on set to capture known reference for scene colors okay but in this case in the case of a color Checker we actually have two options we have color Checker classic Legacy and then we have color Checker classic I'm going to encourage you if you don't know which you have and you often won't in general it's going to be better to go with the color Checker classic because if you go out and buy a color Checker classic today that's what you're going to get you're not going to get a color Checker classic Legacy you're going to get a color Checker classic that's generally a better bet to lay type and by the way the difference between these two is quite minor so it's not life or death it's not the end of the world if you select the wrong one you're still probably going to get a better Foundation than you would have gotten without using the color chart at all so if in doubt select the color Checker uh the color Checker classic I should say as opposed to the color Checker classic Legacy now before we go in and tell resolve to do its automatic bit we need to specify a few things and we need to really clarify what it is that we're trying to do because remember we are working inside of our color managed pipeline right now which just to kind of verbally summarize for us is taking us from our camera color space in this case that's Airy log C4 it is moving us into our working color space in this case that's DaVinci wide gamut intermediate that's where we're going to do all of our color grading that's where we're going to do our look and finally we are going to flow forward from there out to our display color space which in this case is Rec 709 gamma 2 4. so so how does what I'm about to do fit into that process into that pipeline well what I'm looking for as we've already said is a transform which aligns the colors of the color Checker to what they should be minimizes the error between the scene colors as they should have been captured versus the scene colors as they actually were captured okay so that's what I'm looking to do here and I want to do that within my working color space so I don't need to change color spaces I don't need to start in camera space and move into working space or start in working space and move into scene space it all should happen within DaVinci wide gamut intermediate right so that's going to inform the way that I set up these next couple drop down menus because that is my intention I'm going to set my source gamma to DaVinci intermediate Target gamma to DaVinci intermediate and Target color space to DaVinci wide gamut and because I've set things up in this way everything is going to happen inside of DaVinci wide gamut intermediate and for now I'm just doing this on my balance node here in my template node tree I might also choose to do this in a separate node if I wanted to but for now this is a perfectly fine place to run this match and to take a look at what we get so let's hit match here and see what happens okay so there you go so two things have happened here we can see in the vector scope you can see the little dots here that represent our color patches those are all being moved around a bit right it's nothing crazy it's nothing Earth shattering this is a well-shot image it's shot under uh properly calibrated lighting conditions and the chart has lighting conditions which match the lighting conditions of the scene which by the way is an important detail if you have a chart that was lit using different light than the scene received then you will succeed at getting a perfectly calibrated set of colors on your chart but that almost certainly will not translate to the colors of your actual scene which of course is the whole point of the color Checker we don't care about seeing these patches themselves reproduced accurately we care about them providing a frame of reference for getting a more accurate reproduction of the scene itself so you want to make sure that your color Checker was lit by the light that is lighting the scene that's a mistake that often gets made on set where you have a color Checker that's lit up with a camera assistance file flashlight or some other secondary light source because they were just trying to throw up the color Checker in a hurry but the truth is you need that color Checker to be illuminated by the very source that is Illuminating the scene if you want to use it to get better reproduction of all your scene colors rather than just better reproduction of the color Checker itself alright so two things have happened as a result of hitting that match button we have remapped those Hues you can see things moving around either very slightly or a bit more prominently and that's really just aligning the Hue and saturation of these color patches to what resolve knows internally they should have been if captured by a perfectly accurate camera under ideal lighting conditions and in that kind of scenario so this is really just fitting what was captured to what should have been captured by theoretical perfect system but something else interesting has happened as well hasn't it we've actually dropped an exposure a hair you can see how we're getting just a little bit darker and in the same way that we are are aligning our color patches to what they should have been the reason we're getting darker is because the color Checker assessed that that's what we need to do in order to match our gray patches to what they should have been and in particular our 18 gray right here is being dropped down so that it is indeed closer to 18 in linear terms okay so now we know what a color chart is we know how to make use of it inside of resolve and we can look at multiple examples of this here in this timeline but it's honestly going to go the exact same way you're going to go in and you're going to align your overlay to the chart in question now here's one where you're going to need to kind of work around a bit of an occlusion with the uh c-stand knuckle that you see in the upper left hand corner here so if we just go in and quickly do this for demonstration's sake I want to make sure I'm not getting that knuckle inside of my inner sample region because that is going to skew the analysis we don't want those pixels to be incorporated or included in the assessment of where the colors actually encoded onto the sensor so you'll just have to kind of fit it something like that so that everything inside of this little square is just the color patch itself and then we're going to do the same thing for our source gamma Target gamma and Target color space by the way it's perfectly fine to leave your color temp at 6 500 Kelvin because that is indeed the native white point of The DaVinci intermediate space that we are working in and I'm going to hit match here and you can see different fit different solution was arrived at here then in the other shot but we're doing a good job of getting things back to neutral and this shot really brings me to an interesting point that I want to emphasize in the case of this shot if we're looking at pure Aesthetics and you know setting aside concerns about accuracy if I look at this image if I go off and then on I personally feel like I might prefer this original reproduction of the image maybe you do too and this is where really the third question that I want to answer for you today comes in which is okay we know what a color chart is for we know how to use it now the question becomes when should we use it and do we have to use it if it's in there the answer to that last question no you absolutely don't have to use it here's the prescription I'm going to give you when it comes to color charts if you have a color chart in a project and you receive a frame where a color chart was shot and that color chart was shot under lighting conditions which match the lighting conditions of your scene again important detail that we want to make sure otherwise I would just not use the chart at all but assume you do have that chart assume that it was properly lit go ahead and run the color match just see what it gives back to you you can either take a little bit of it you can toss it out completely or you can choose to say hey this actually gives me a better more balanced starting point for my image so no you don't have to use all or even any of your color match Once you pull it but now you have the advantage of seeing the image balanced so that the colors in your color chart are more accurately reproduced compared to what they should have been captured captured as by a perfectly accurate camera and in the case of an image like this if you wanted to go in and split the difference that's an option you have as well you could go over to your key palette down here and set your key output gain to 0.5 and now you're just getting half of that sort of rebalance of the image based on the response of the color patches here so you could have all of the color match none of the color match or some percentage of the color match and one of the rules when should you do which how do you know when to do which ultimately it just comes down to your eye and it also comes down of course to the creative intent of your collaborators maybe this warm look that we started with here maybe this is the exact intent of the filmmakers this is something else that you want to be sure of and you want to discuss with the people you're working with if they come in and they see that you've done your first pass and balance everything out to have neutral highlights neutral Shadows neutral mid gray everything exposed into a sensible default position but they intended the image to be warm or the intent of the image to be bright then they're going to come in and they're going to be surprised they're going to say what did you do right so I just want to be clear that the color Checker is there to support you but you don't owe anything to the color Checker it's there to work for you if it is working for you then you you should use it if it's not working for you then you should feel free to throw it away but that's a good overview of the way that color charts work in general and the way that the color match feature Works inside of DaVinci Resolve as well as when and how you might want to use it to get better grades for your images

Channel: Cullen Kelly

Views: 13,554

Keywords:

Id: iMwEmiXDG64

Length: 12min 48sec (768 seconds)

Published: Wed Jun 21 2023