Tips for Compositing Digital Backgrounds – After Effects Tutorial

hey guys in this tutorial i want to share with you some general tips for compositing special effects we'll cover four different tricks you can use when you're working with green screen footage or if you're adding in a cg element to a scene and no plugins are needed for any of the effects we're gonna do in after effects we're gonna look at color matching adding a light wrap adding motion blur back onto our footage and we'll also look at how you can incorporate some practical colored lighting as well now as i mentioned these tricks are going to work on green screen footage or even on cg elements you're adding into a scene since in both cases the end goal is to get your subject to look like it exists in the same world as the background and you can use these tips for realistic composites stylized composites such as a music video or for something as simple as a digital background for a youtube show finally before we start i do want to mention that i'm not going to cover how to actually key green screen footage in this tutorial but we do have an article on the premiumbeat blog that walks through the method that adobe recommends i actually use that method all the time now even in place of third-party keying plugins that i own and a link for that post will be in the description all right guys let's start by learning how to color match our footage all right in after effects let me just kind of break down the scene i've got and kind of show you guys what i'm wanting to accomplish here so i've got this spaceship you can see i've added into this city shot and i've already kind of tracked it in here but i want to get this to essentially match kind of the colors of my scene even more now you can see i'm going to separate this i've got it in two passes i've got the lights for the ship on one pass then we have kind of the ship image right here and i'll zoom in here and we can see it already matches pretty close as far as the coloring goes you can kind of see the dark blues here which will probably be blacks but with this kind of color grade on this footage we can kind of see that matches i'm just going to show you the original ship what it looked like so you can see here go ahead and turn off all the effects on it this is what the image originally looked like just raw and all i've done to kind of give it a little bit more of a bluer tone because i didn't want to kind of color grade it to get it to match was i added a human saturation effect and kind of offsetted that and then with lumetri color i come in here and add a little bit of blue to the shadow tint and things like that just kind of get as close as possible before we actually do the color matching so we jump back over to this scene we can see the ship again looks close but we're really not getting any of these kind of blue color reflected back onto the ship and it's not really kind of selling the scale of the ship just yet for me so let me show you guys a real simple way to do a color matching effect for something like this so i'm going to right click and do a new adjustment layer and on the adjustment layer we're going to apply a gaussian blur so under effect come up here to blur and then gaussian blur and i'm actually going to move this below the spaceship image and what we want to do is we want to crank up the blurriness quite a bit and go ahead and click on the repeat edge pixels and the idea here is really just want to kind of smear all these colors together so when we sample them we're getting a pretty accurate sample because if we didn't do this we might use the color picker on something and it might just pick up a little bit off color this is just a better way to kind of get you a color average and what we need to do now is apply a tint effect to our image or in my case here the spaceship so i'm going to select it and come here to effect and it's under color correction we're going to select the tint effect and what we need to do is we need to sample a dark color and a light color in our scene and that's going to be the light that's kind of reflected back on our model we'll adjust that tint amount and things like that in this case with the ship here in the sky we probably just want to sample colors relatively around it up here in the sky that typically is going to look the most natural but again depending on the placement of whatever you're working with you'll want to sample colors from around that area so i'm going to select this map black too i'm going to use the color picker and i'm just gonna click kind of in this darker blue area over here in the sky and then i'm gonna slightly map white to and i'm just gonna select one of the lighter blue areas right up here kind of close to the ship so now you can see we've done that and i'm gonna crank the tint mount all the way down to zero now and we'll adjust that in just a second let's go ahead and turn off that adjustment layer and now we just need to gradually increase that tint effect until this looks natural and you can see setting this around 50 here for this particular shot looks pretty nice and also helps sell the depth like the ship is really big and it's kind of further off in the distance you can kind of see this happening actually in the real footage the buildings and things that are up here close you know they're pretty clear and then further off kind of here on the horizon line we kind of that faded blue appearance as it gets less contrasty the further away it is and that helps kind of sell the scale of this spaceship in this scene [Music] now here's another example shot i've got this is with me on a green screen and kind of got this bokeh kind of trees background going on and what i've done here is the exact same method so i created an adjustment layer and i applied a gaussian blur to that i wanted to sample some colors from these trees back here and i'll go ahead and look at this i already have the tint effect applied to my footage and i just sampled kind of one of these darker oranges here and then the lighter orange color there go ahead and check this on you can see what a difference this makes this is very subtle it's only on 10 percent and in most cases unless you're working with something like really big in a sky you're probably going to want the tent amount to be very low probably around 10 to 15 percent but you can see what a difference this makes here on this just having that little extra 10 boost of that kind of color reflected and what it's kind of emulating here is like you can imagine there's other trees kind of around me and so we're getting the color cast from that environment around our subject and that's what's reflecting back kind of giving us more of a realistic composite there you can see that kind of adds those orange colors to the dark areas and in the shadows and here's another scene kind of an abstract fantasy scene with this whale floating above the clouds i've also done the color matching effect on this you can see what the before and after looks like with that again i really like this technique just really simple and easy using the tint effect to color match your footage next let's take a look at how we can add in a light wrap onto any of the elements we're compositing in our scene all right guys to create our light wrap effect we're actually going to come back to this scene here where i'm standing in front of the trees and kind of the bright background i think this will work pretty well for our light wrap scene now there's definitely certain situations where a light wrap is kind of appropriate than others where it's not it can actually look kind of weird but we'll talk about some of those but first let's just kind of go ahead and create this effect and kind of look at what goes into this process so you can see i've got two clips here i've got me on the green screen i can toggle that on and off and i have my background footage here it's kind of out of focus bokeh so what we want to do for the light rav is i'm actually going to select my background i'm going to hit ctrl d command d on a mac we're going to duplicate that we're actually going to drag it above our green screen footage and this is what we're going to create our light wrap effect on and the first effect we need to apply is a gaussian blur so let's come here to effect and over to blur we're going to select gaussian blur and we can blur this out a little bit we'll look at what this does a little bit later but it's very similar to kind of what we were doing with the color matching effect we just want to kind of get a color average from this and you'll see how this works a little bit later on so i'm just going to increase this something like 50 for the time being now the next effect we need to select is the set matte effect so let's come over to effect that's going to be under channel i believe and it's going to be set matte and what we want to do on this is we actually want to select our matte to be our green screen footage if you have any effects applied to it go ahead and select effects and masks here and we also want to select this to invert the matte now right now you can't really see what's going on so i'm going to solo the layer we're working with here that top background layer so you can see what it's doing here we're getting basically a matte of our green screen with our background footage and this will make more sense as we continue adding effects so the next effect we need to add is a channel blur effect so under effect we're actually going to be under blur here and we're going to select the channel blur and what we want to look at here is the alpha blurriness i'm going to check on repeat edge pixels now let's go ahead and increase this blurriness and you can see we're obviously blurring the edge so what we need to do is we essentially want to kind of cut off this background and only have our subject here but we want to have this extra light that's kind of wrapping around which is going to create our light wrap effect so you can kind of get an idea of how this is going to work so in order to do that we need to apply another set matte effect so let's come up here to effect then under channel we're just like set matte and we want to select our green screen footage again here so i'll select that again if you have anything effects or anything make sure you select that as well and now you can see the result we're getting we get kind of that blurry light wrap coming around our subject and because it's based off the background it's matching perfectly let's look again at really what's happening here with these other effects so we have this gaussian blur if i bring this all the way down to zero it's not really going to blur the background at all so we're getting kind of very sharp colors coming through and that doesn't really quite look correct you can almost look like a transparent area on your subject now in my case this background is already kind of blurred from the bokeh out of focus effect so it doesn't look as prominent but i'm going to set this probably on 100 just so we can kind of really blur out that background and then with the channel blur here this alpha blurriness that's really how much light wrap we want to have wrapping around our subject and so you can see how that's working there so what we can do now is i'm just going to go ahead and unsolo this and let's go ahead and just kind of look this on and off you can see how that light wrap effect is working now sometimes uh leaving it on normal will look pretty good you can see i'm getting a pretty good looking kind of light bloom effect around my hair but down here on my shoulders that doesn't look quite right some kind of dark color cast coming through so you'll probably want to set this on a screen blending mode and you can see that looks more correct down here and it's still going to be bright here around the brighter areas where the light would be blooming now speaking of light blooming that's really where you're going to actually get a real light wrap effect in real life is whenever the background something in the background is probably going to be very bright white and typically overexposed and that's kind of an artifacting effect just with the lens and the camera now here's another example here i've got just a solid white background you know this is obviously a stylistic choice if i just want to have somebody talking with a white background you can see i've got a light wrap applied here and again it's a distinctive look if you want to have that effect like it's very very bright and the light's kind of blooming around the subject i can toggle this on and off so you can see this is what it looked like before and then afterward so again this might just be a stylistic choice but again you could use it with something like this as well now be sure to use the light wrap effect sparingly and lower the opacity of the effect to keep it subtle when i do use it i typically just use it to slightly soften the edges of a keyed subject which can make the blending of the two elements look a little more natural but again this is always going to be dependent on the composite scene you're working with next let's look at how we can add motion blur back onto keyed footage so one of the biggest telltale signs of a green screen composite is usually going to be the lack of motion blur on a subject when they're moving around on screen now let's take a look at a little bit of an extreme example i've got my hand here waving around on screen kind of doing a karate chop action and i've already keyed this footage and you can see there is some motion blur here we're seeing but a lot of the motion blur is actually on the subject whereas we're not getting any of the motion blur kind of outside of this you can see it's kind of a fairly sharp cut off there especially in areas like this where the motion layer that was probably existing a little bit further out from the hand has been keyed away because of the green screen you can even see through this motion there is even a little bit of green artifacting left here and that's kind of where it's right on the in-between of the motion blur and something between the fingers there and that's pretty typical now by adding motion blur back onto our footage we're going to get more of a realistic movement and it won't have that stuttery feel to it and also it's going to help remove some of that green artifact that's left you know kind of in between the key due to the blur amount and to do this without any plugins in after effects it's pretty simple i'm just going to select my footage and you will need to pre-compose your green screen footage if you haven't done that yet so with that footage selected i'm going to come here to effect and i'm going to come down here to time and just off the screen here i'm going to select pixel motion blur and once we apply that effect you're going to see we get kind of an artifact looking result we can see a lot of stutters here so the first thing we need to do is come here to the shutter samples and the default s5 i recommend increasing this to something like 12 or 16. i just went ahead and bumped that up to 12 and as we kind of sample through this footage i go ahead and turn this pixel motion blur on and off you can see what a difference that's making by giving us that added motion blur to the outside edges and it also kind of helps remove that green artifact that's been left on our footage and this will kind of smooth things out so you don't get that stuttered look on your green screen footage that often is a telltale sign that something's been composited in you can even add motion blur on objects that pass in front of something that's been composited into a shot such as a screen replacement so let's take a look at another example i have here and again this is something i often see even in blockbuster movies usually with computer screen replacements or even windows or maybe they add in a fake background a lot of times they don't add in that extra motion blur on whatever object passes in front of it so you can see i've got some footage here of an ipad if i go ahead and solo this you can see i had a green screen just image on the ipad so i could key that out and now my hand comes across this to kind of type on the ipad we can see some of that motion blur detail of the fingers around the fingers here has been removed and we're also getting a little bit of a green color cast here from the screen so the idea here is we can create a mask just around this area of our footage and apply pixel motion blur to that because we don't want to apply to everything on this because we might get some artifacting with the shadows and stuff like that and there's really no need for us to apply it to everything that's on the screen so what i've done is i duplicated the ipad footage and created a copy of it and applied it on top of everything go ahead and sold this you can see what i've done is i just created a mask around this kind of area of the screen where kind of the fingers are passing over the green screen area and i pre-compose that because you will need to do that before you apply any pixel motion blur to that and then if i go ahead and zoom in here let's go ahead and turn on the pixel motion blur for that you can see how it's just adding a little bit more motion blur on the edge of the fingers it helps kind of wash away that green color casting we're getting but again the ultimate goal with this is just to smooth out that kind of frame stuttering effect when everything is moving in front of that green screen composited area one last thing i do want to mention is if you're using the pixel motion blur on keyed green screen footage i find the results work pretty good occasionally you will get artifacting but you can even see in this extreme example with the hand the results are pretty solid and the great benefit of pixel motion blur is that it is included with after effects now if you need even more accuracy you might want to check out the third party plug-in real smart motion blur it will give you better results and does render quite a bit faster but again i have gotten very solid results when i am using pixel motion blur with keyed green screen footage finally let's take a look at using practical colored lights on your subjects to match the scene they're going to be added into you can do this in a variety of different ways two of the easiest being using colored gels or using colored rgb lights gels are definitely a cheaper option that's actually what i'm using here and you can usually pick up a set for around twenty to thirty dollars the biggest pro for them is that you can use them on bigger lights that can output a lot of color alternatively smaller colored rgb lights have really been on the rise in popularity over the past few years they make it really quick and easy to dial in all different kinds of color combinations you're going to need the only drawback being they likely won't put out as much light but the idea here is adding that extra colored light to be reflected onto your actor when they're in front of the green screen to better match the final background composite that's going to be added in however another way you can use them creatively is actually light a real world scene where you're going to composite in a cg element later here's a quick example scene i'm just kind of illustrating this i've got this orb that i added into the scene like it's sitting on the desk here and it's kind of got a red glow to it and what i've got is just a light with a red gel facing down above this table you can see that's actually what's illuminating the table but the illusion here is that that's actually coming from this orb and so this is a kind of a use case of using practical lighting with gels and kind of colors in the scene just better incorporate the cg element that i'm compositing into it finally if you guys are interested in even more compositing tips for special effects check out a tutorial i did for rocketstock which is compositing tips for adobe after effects i'll have a link for that one as well on the blog post alright guys hopefully you enjoyed these compositing tips give us a thumbs up if you did i'm charles with shutterstock and i'll catch you guys on the next one

Channel: Shutterstock Tutorials

Views: 25,923

Keywords: shutterstock, shutterstock tutorials

Id: WmUTzxhdkZ0

Length: 16min 21sec (981 seconds)

Published: Thu Oct 29 2020