Linear Workflow in DaVinci Resolve and Fusion

whenever we are working in fusion we should almost always be using a linear workflow let me explain to you what exactly that means when we have to do it when we can avoid it what the reason for this is and of course how we can set it up in fusion i'm covering this topic a lot in my compositing course as well which you find on my website but it's such a basic topic that i think everyone who is using fusion should know about it which is why i want to do something for youtube as well so let's have a look [Music] let's start out super simple by looking at a plain gradient just a background note in fusion where i say left black right right and in between values and if i look at this in the viewer and i can open a second viewer and open a waveform monitor view waveform so the waveform shows me the brightness from left to right for the pixels in the image so from left to right i'm going from zero to one or in this scale it's actually going from zero to 100 but inside fusion we have everything from zero in the zero one uh range one meaning right zero meaning black and we have a linear curve so far that's easy right so what's so great about linear well it's so easy in the real physical world right if i want to know how much light falls into the camera let's say i have one single light bulb turned on a certain amount of light falls into the camera i turn on the second one well two times as much light falls into the camera that's a linear relationship now the only problem with this is even though it's simple our eyes don't work this way our monitors don't work this way fill never work this way and our camera sensors don't work this way and there's a reason for this and that's basically that we need to be able to deal with bright sunlight when we go outside so the sun is like million times brighter than everything else so we still want to see everything else despite super bright sunlight right so that's why this encoding here this linear encoding is not very good for us in order to see details in the shadows which we need if the sun is shining right so putting it very simple and that's why our cameras don't encode this way and monitors and sensors and film and so on work differently and they have different types of adjustment curves you have probably heard of gamma curve or of log curves so let me use a gamut node which is adding a gamma curve in this case so if you want to see how our typical film footage would be encoded if i create a clip for youtube then to this gradient as captured by the camera we would apply such an adjustment curve which says basically in the black range put more data use more a larger range of data for the left part here for the darker ranges use more data in this area and use less data less latitude here in in the in the right area so that's what a gamma curve does um if you go for log footage here is a log curve then this is even more amplified right and then there are different mathematical functions logarithmic function and here we have exponential functions in the in the gamma curve i'm not going into the mathematics in this video just keep in mind there is always an adjustment curve applied now in fusion we can work with those adjustment curves but we don't have to and the luxury we have in resolve and infusion is that we have much more bit depth than what your camera has and to put it very simple so your camera has 8 10 12 bit of data available per channel to record luminance information but in fusion or in davinci resolve the default is 32 bit and that just means that there's much more data available to save those lower shadow values and save out of range values and other stuff and here the advantage is that we can remove those curves without losing any shadow detail inside fusion or inside davinci resolve well what does this mean for for working right for fusion for editing for color grading well it just means that some of the tools we are using need to be aware how the encoding is performed in order to function accurately let me show you an example and i just use a very simple blur as an example here and i apply it to this wonderful photograph here so i have this photograph and this is coming from the internet so any jpeg photograph would be encoded with srgb typically it's a standard color space and gamma correction for for photographs and i can remove that curve here remove the srgb with a gamut node and then you see it just looks darker and i have these tools right now are doing nothing there's a blur which is doing nothing right now and after that i have again a gamma curve where i'm adding the gamma again so what does that mean so here in the first line i can just apply a blur without doing anything just directly and can see what happens and in the second line i first remove the gamma correction that is applied then i apply my blur and then i add the gamma correction so effectively i shouldn't be doing anything different except that i am applying the blur on linear space whereas here i'm applying it directly on the photo let me do a left and right comparison so on the left side we have the directly being applied in srgb on the right side we have it applied on linear space and let's see what happens and you should see that on the right side we are maintaining the luminance on the left side the image gets actually darker so you see directly even a simple blur you see a difference between left and right and this would get even stronger if i was for example directly working on log footage let's say we have log footage and i'm simulating it here with the cineon tool i can convert from linear to log so i'm just doing that conversion here and let me show you this version so if i look at the log footage log footage typically looks a bit flat not a lot of contrast and then i go through the same flow and we can again do a left right comparison so on the right side is my linear raised version where i do the blur and linear on the left on log and you see the result is even stronger so you see even a simple blur tool depends on the scanner correction why is that well the blur interpolates pixels inside the blur node and it needs to know how it does that so when you blur something every single pixel is kind of spread around to the other pixels and for this it needs to understand um what does it mean if a bright pixel has say 50 impact on a neighboring pixel or 30 impact and for this it's important to know is it a linear curve or is any other curve being applied and this is where it makes a difference i can show you that even more drastically with this little academic example here i am just showing you one line here on an 11 by 11 pixel grid and you can see what is actually happening to the pixels in this i have again a transformation so in the first area i can blur here and let me bring it into the viewer so i can blur one pixel out to the other pixel so it's getting blurred out um and i can do the same after going let's say after removing the gamma curve which is happening here and you will see again same blur but this is the first result and this is the second different result so the pixels are being distributed differently depending on how the gray values are being understood and they are impacted by this color conversion and blur is not the only tool here basically every tool that re-interpolates pixels from one position to a new one has this kind of impact this goes even for things like transforms and merges let me demonstrate just a simple transform you think nothing can go wrong right so we have a transform and let me just let me rotate and with the low pixel resolution you see what's happening so pixels are getting interpolated like onto the diagonals as i rotate and this is if i rotate directly but if i did the same in linear space you see i get a different result and in log again even a different result now the differences may not always be as drastic as what i'm showing here right now but you see there are differences so we should know uh what our tools expect that we are using and they are designed in fusion to work in linear now why is that for example in the davinci resolve color space you're not working in linear you can work in rec 709 or in asus cct which is basically a logarithmic adjustment so the color page tools in resolve are not designed for linear but in fusion they are designed for linear and the reason is just in compositing you have fusion has some 250 tools and you can build your own tools you can do your own scripting so either you would have to demand that every single tool that was ever built for fusion has to comply with every possible color space or you have to make another assumption and that is that you're working on linear and you can easily enforce that by just bringing the footage to linear as you enter fusion and bringing it back as you leave fusion so let me show you how i actually set this up and i do it the manual way in davinci resolve now and there's also an automatic way just to show you here in the davinci resolve project settings under color management i have my color signs set to davinci yrgb which is a so called display referred color science color management which is just a very fancy way of saying you are doing it yourself you are responsible for doing the color management not resolve is not doing anything for me right now then there are the color managed versions da vinci color managed and asus and i think i will dedicate a separate video to those in those cases davinci resolve is doing the linearization for you in an automatical way and there are some quirks to it which um i should discuss separately i think so for now the manual way which is also great to understand what's actually happening so da vinci y rgb is my setting here and let's say i bring anything into fusion from the media pool or from the timeline or it doesn't matter how i go to fusion let's say i had the photograph before let's say i use this clip now i don't even know what it is let's see oh this one here it's from a black magic training video um then i can add a gamut note afterwards or i can add for log footage i can add the cineon log tool this one is actually log footage so i would go for the cine unlock tool and in that cineon tool i find here blackmagic film and then i would have to remember what this was what camera this was and i don't remember i'll just select one just to show you the effect so you see that i am going from from log i am which is like the flat look like low contrast i'm going to linear which typically looks very dark and then i can do my compositing whatever you want to do i'm not doing anything now just you know for illustration i'm doing let's say i'm doing something whatever it is and then when i'm done i can go back to my original version i can just copy my cine log tool here and go back here i went from log to lin and on the way back i should go from lin to log and if i haven't changed any other setting and just copied it i'm going exactly back to where i started right so here i started and let me go into two viewers again here i'm back to the same place where i started and the cine log tool this would be for log footage and there are quite a few presets here for different cameras and so on so this way you can manually convert log footage into linear footage and back um you could also do it directly on the media in node so instead of putting the separate log tool i could go into media in and here i have source color space and source gamma space and in this video i'm talking about gamma so linear non-linear it's always gamma so here i can choose log and then i have the same tool basically so this is the same tool as this senior tool which i have available here this is for log footage for rec 709 or srgb or anything like this you would use the gamut tool so you have seen it before let me add it again gamut and it's again it's also available so if you go into the media in let me use it here maybe i can go to space gamma space space and then here i have the different gamma spaces and this was i think a photograph so i have the photograph srgb i can click here remove curve and you see it gets immediately darker and then the media out does not have this kind of control so if you have at the end the media out in resolve um then for some reason it doesn't have this but you can add the gamut node before and that's basically why i'm showing you this so i can add the gamut node at if i want to go back to srgb i can or if i go to rec 709 which is most likely what i may be using for final delivery or rec 2020 or whatever it is you have the options here um for rec709 just to mention it there you see two different ones there is a rec 709 display and the rec 709 scene the scene one is the original rec 709 definition the display one is a slightly different variety and i always forget which one it is so if you have to do pure rec 709 you have to do this however in davinci resolve many people use like rec 709 gamma 2.2 or rec 709 gamma 2.4 and what that is in da vinci resolve is the rec 709 standard which defines the color space the gamut as well as the gamma and then they change the gamma curve which in that case does not include a certain linear component of the gamma curve now that sounds probably super technical and so on and it gets even more scary if i show you in fusion one second how i would do that but i believe it's the easiest way in fusion so if you have to if you want to use this rec 709 gamma 2.2 or gamma 2.4 in the output space here you can just go to custom and custom will by default give you srgb which has the same color space as rec709 but different settings for gamma so there are chromaticities which define like this triangle here which defines the space for the rgb values um loosely speaking and then there's a definition how this brightness adjustment is being performed and the default in custom is for srgb but if i remove that limit here then i have exactly what davinci resolve in other pages calls rec709 gamma 2.4 so the default definition of rec 709 and the definition of srgb they have a certain linear component so the curve starts in a linear way and then there's an exponential curve again forget the mathematics just to say there is this component in the standard definition but if you use this rec709 gamma 2.2 gamma 2.4 uh one way to get this gamma 2.6 whatever is to put the linear limit to 0 and then enter whatever gamma you want 2.2 2.4 2.6 so that would all be possible just by changing this gamma here okay so i think this is the easiest way to set this um there are other tools in davinci resolve let me show them to you so in davinci resolve and this is not available in fusion studio this is a resolve effect in davinci resolve you have from the open fx tools you have the open fx color tools and you have here a color space transform so this is an effect from the resolve color page um and here you have the input and output color space you have here use timeline and so on um so basically you can control the gamma separately here and here you have the same definitions that you see in other areas of davinci resolve so if you want to use rec709 gamma 2.4 you you can do that here and actually you have here rec 709 so you can can set that separately here now the problem is with this tool this is more aligned to what you see in other areas of davinci resolve the downside is this is first of all it's not available here in the media in or in the loader nodes so you would always have to add this tool manually that's maybe not the biggest problem but there's another thing and this comes to viewing the image i showed you how i can transform the image but actually i also want to see it right and once i remove my gamma curve it looks dark so the solution for this is to turn on a viewer lut infusion and the way you do this is you go on the lut symbol if you go into this triangle you can select different ones and you almost always want the gamut view lot which i already have selected and then you activate it and then it is applying a lot and in my case it already looks the way it should look and that's probably because of my default settings for this gamut view lot but you can check and go here on edit and what you have here is again basically the gamut note being applied in the viewer to whatever you are showing in the viewer and here i'm just saying well source based nothing do nothing and output space add gamma at srgb because my monitor like most computer monitors works with srgb so calibrated to srgb um and this way i have whenever i have my lut turned on i am looking at the image in srgb if you have calibrated your monitor to a rec 709 for example you could do that as well could find the correct setting here rec709 scene or even go to this custom and this way do a turn the linear limit off and do a rec 709 gamma 2.4 or gamma 2.2 so you could do this directly here in the gamut view lot once you do this you probably want to right click here and and save your settings settings save default so that the gamut view is always doing the same thing when you are turning it on so there we have the simple workflow so you bring your footage whatever it is into linear do your compositing and then bring it back or bring it towards your final output depending on what your next steps are so in davinci resolve typically you come from the timeline and you want to send it back the same way so if you have log footage in the timeline you bring it to linear but then you bring it back into log footage and then you do the final color grading etc at the very end in other cases determine the individual sources and bring them all to linear so you have a common basis so photograph jpeg most likely srgb stock footage most likely rec 709 camera footage in many cases log footage arri logs canon log etc etc so you can set it up this way do you always have to work in linear well no it's generally a safe assumption but there are a few cases where you may not want to work in linear if you are only doing color corrections then you are not causing any harm if you are not working in linear for example if you only do let's say you do a gamma a curve correction let's say you bring in color curves here those curves um are not different than the gamma curve that is applied before so if i use that in linear or if i use that in srgb the curves tool will behave differently same with brightness and contrast or with color corrections but as long as i use only color correction tools they will behave differently but you will not be causing any mathematical error in the compositing if you know that the tools behave differently you adjust them differently the values the parameter values will look differently but you're not causing any error but that also means that if you want to if you prefer to work in srgb or in rec 709 because you're used to color grading in rec 709 and you may find it convenient to do so and you can do so so whether it's a curves tool or a color corrector you can bring your footage into rec709 do your color correction bring it back if you find the tools more convenient to use that way it's really just about how the tool reacts to the footage how convenient it is to use it another area might be green screen so in principle you can do keying on linear footage but sometimes you may observe that the matte separation may work better after some pre-processing so whether when you use the delta keyer or a luma keyer in some cases that separation between background and foreground may come out better if you are working in non-linear so that's definitely something that you can try generally the tools work fine in linear but if you're only doing the green screen extraction and you're not doing any scaling and any more other compositing tasks you only do the calculation of the the alpha channel then you can also do that in other color spaces and if you get a better result from doing it in in rec709 for example if you get a cleaner alpha channel there's nothing wrong with using that okay that was a lot of information but it's not too complicated at the end there are like three tools the gamut node the cine log tool and in davinci resolve the resource color space transform tool and if you apply those find the correct settings for your camera you can easily set up a linear workflow manually go back afterwards determine your view a lot most likely srgb for most monitors for viewing and with that you should be set what's left is resolve color management and aces and that's a topic for another day thanks for watching [Music] it's us

Channel: VFXstudy

Views: 6,707

Keywords: Blackmagicdesign, Blackmagic, DaVinci Resolve 16, DaVinci Resolve, Fusion 16, Fusion Studio, VFX, Fusion, visual effects, compositing, color management, color space, linear workflow

Id: BgrM-SUgCLc

Length: 25min 3sec (1503 seconds)

Published: Mon Oct 26 2020