Realistic Film Emulation Texture with MTF in DaVinci Resolve

hi guys welcome back to the channel today we're talking about how you can improve the texture of your film emulations by implementing a technique called an MTF first I'm going to explain what an MTF is and then I'm going to show you two ways to emulate it in Venture resolve first to understand what we're trying to replicate let's review STS from projects captured on 16 mm film I've gathered an example from a music video a commercial and a film if we look closely we're going to notice that the overall texture feels so soft now let's compare them to three Stills that are captured on digital cameras do you notice how what is in Focus looks much sharper we can even see the pause of the actor in this example if we wipe between this still from beef filmed on an AR alexam mini LF in this one from a movie called we animals filmed on Ari 416 you can really see the difference between the amount of detail we can see on the right notice how sharp her glasses are we can even see the pores in her skin whereas on the left we don't have this level of detail the features in his face are much softer and we can't really see a lot of detail in his beard and hair well the reason is that one of the main characteristics of fil prints is a lot of detail in high frequencies and if you're wondering what high and low frequencies are in an image let's review this example put simply low frequencies are areas in the image that are plain where there is very little variation in pixels next to each other for example P the yellow cardigan down here the red seat belt over here the seat as well and the skin tones in contrast high frequencies are areas where we see a lot of contrast between pixels next to each other typically those would be fine details such as edges and textures in this example the detail in her lips her eyelashes the strings of hair and the striped texture of the seat would live in the high frequencies the loss of detail in high frequencies when recording on film is called MTF which stands for modulation transfer function and if you look up the technical data of kodx 5222 negative for example you're going to be able to see the exact modulation transfer function curve that is applied and notice how between 20 mm to 100 mm spatial frequency the loss of sharpness intensifies and so this is one of the main texture characteristics that makes film so beautiful and that's enough theory for today let's dive into resolve and see how we can create our own MTF I'm using a clip from Red Dragon X and I've already set up my note based color management I have an ID in my group pre clip that takes us from red white gamut log 3 G10 to AR log C3 as this is my preferred timeline color space I have also applied some noise reduction and a bit of sharpening to compensate for the softness introduced by the noise reduction and at the end of my pipeline in my group post clip I've applied Aris technical lot that takes us out to rec 709 gamma 2 2.4 in my project settings I've also ensured timeline color space is set to AR loog C3 on the clip level I have applied a simple exposure in white balance adjustment and I've taken advantage of the brand new look Creator o effects with the default 35 mm preset loaded I've just turned off some of the effects such as halium Bloom and grein but everything else is left to default now let's dive into method number one Edge detect I'm going to open open up the effects Tab and search for Edge detect let's apply it to our node by default the mode is set to RGB edges but I'm going to switch it to grayscale edges what Edge detect does is it pulls a selection on the hard edges of our image and we can see the edges that are currently selected in white as we already know edges and areas of high contrast between neighboring pixels are the high frequencies of your image so we can use Edge detect to select which high frequencies exactly we want blur later so let's refine our selection I'm going to reduce Edge width because I want the area that I'm affecting to be more narrow gamma controls the threshold of the frequencies we're going to be affecting lower values select more frequencies and higher values select less I'll keep tweaking until I'm happy with the selection and I think this looks good okay so now we essentially have pulled the qualifier on our high frequencies and here is how we can use this key to start not blurring them first I'm going to create a new serum note and disconnect it from Edge detect our connect is input to our source image and I'll grab the output of edge detect and pipe it into the alpha input of my new seral node where I'm going to be doing the blurring so I've just passed on the key we pulled to our new node and any corrections that we do in this node is going to affect these pixels in white and we can confirm we've passed the key correctly by double-checking our node key down here now that this is set up let's start adding some blur I'll open up the Blur tab and start increasing the radius I think right about here looks good to me we've lost some of the sharp detail we had before but we haven't affected the overall quality of the image and to me this brings us one step closer to a realistic film emulation I'll grab a still of this and let's jump to Method number two custom MTF compound node first I'll create a new grade version and delete these two noes so with this method we're going to build our own frequency separation tool with noes this may seem complex at first but it's all going to make sense as we break it down so I'm going to build out a note tree and then we're going to explain what each note [Music] does all right so let's break this down the first note is just an empty connection Noe which is why I have labeled it no then our note tree spreads out out into two separate branches let's start deconstructing it from the bottom we already know that the MTF reduces detail in high frequencies but how can we separate low from high frequencies without a no effect well if we apply blood to our entire image we'd only be getting low frequencies this is because as we said low frequencies are areas that are plain with little detail and the way to get less detail is to Simply apply blur so I've increased the radius in my Blur tab to 0.56 then I've taken the blood signal and I've passed it onto the bottom note of a layer mixer structure if we break down this layer mixer we'll see that the note at the top does nothing it only passes the information from the original image and the bottom one is getting our low frequencies from our blood image next the composite mode of our layer mixer is set to a subtract operation so essentially we're taking the original image and we're subtracting the low frequencies from it and as a result what we get on the other side of the layer mixer is the high frequencies and we can confirm this if we switch on highlight mold do you see the white lines similarly to what we saw with Edge detect these are the high frequencies and we can control how much we are selecting by increasing or decreasing the blur in the low frequency threshold node down here if we increase the blur further we're going to be grabbing more high frequencies and if we reduce it we're going to be bringing down the threshold of our selection and we can keep jumping between these two nodes in highlight mode and refine the selection until we're happy okay so we have a selector down here and this note is reserved for our blurring operation to the high frequencies you're going to notice we have one more layer mixer at the end of our Noe tree and its composite mode is set to add we can see that it's getting one signal from the blood image hence the low frequencies and another signal from our high frequencies that we haven't aled just yet so the result we get is nothing and this is because these two layer mixes essentially cancel each other out now that we've built what looks like a complex frequency separation tool let's put it to work and let's start losing some detail in the high frequencies our aim is to soften the detail slightly but we don't want to make the image look out of focus I'll jump to my high frequency blur note ha and I'll start increasing blur to about 0.53 you can combine the effect with midtone detail as well so let's decrease midtone detail slightly please note I'm overdoing it a little bit to make sure this is visible on YouTube okay let's zoom out and see what we've done if we disable and enable all the nodes do you notice how we've defocus the fine details again we're not affecting the overall quality we're just adding some softness to the texture but the effect is subtle and it's completely different if we were to apply blur to the entire image in fact let's compare the two so you can see see the difference for yourself I'm going to select all the nodes and create a new compound node I'll label it MTF let's grab a still of this and disable the compound node I'll create a new serial node and apply blur to the entire image let's wipe the steel and see if there is a difference do you notice how our MTF is much more subtle and believable the effect is only applied to the high frequencies so we're not deteriorating the quality of the image we're just giving it a more filmic look by emulating one of the key characteristics of film negatives an MTF curve I would advise you to save this compound node as a power grade so that you can quickly apply it to your node tree the next time you're asked to create a film emulation look if you made it this far thank you I know this may have seemed like a complex topic but hopefully now you have an understanding of how to better emulate the texture of film in your own work as always if you enjoyed this video please like subscribe subsribe to the channel and I'll see you in the next one [Music]

Channel: Marieta Farfarova

Views: 8,153

Keywords: color grading, davinci resolve, colour grading, color correction, grading, Hollywood looks, post production, colorist, filmmaking, grade, film emulation, accurate film emulation, MTF, modulation transfer curve, vintage lenses, film texture, film characteristics, film look, 16mm film, 35mm film

Id: bc9HmaS1a68

Length: 10min 8sec (608 seconds)

Published: Tue Jun 25 2024