Using Kdenlive’s color manipulation effects, it is possible to transform a real movie into a cartoon, giving the illusion that the actors are drawn by hand instead of shot with a video camera.
The two most common forms of amateur production are live action (film with actors) and cartoon. Sometimes, however, it happens that you want to do a combination of two things: insert cartoons into real footage, or insert actors into cartoons. The advantage is that drawing human characters by hand is rather uncomfortable, unless you want to stylize them. Instead, if you take a shot, you just need to put the actor in front of a green screen. If you are Dick Van Dyke, you had the opportunity to dance with penguins in a world designed within the film Mary Poppins. If you are not, you have not had this opportunity. So far, of course, because with Kdenlive you can insert yourself into a cartoon, also changing the picture appearance to look like cartoons. In fact, we are not satisfied with entering the cartoon, but we also want to transform the actor into a drawing in order to blend him with the background (hand drawn). The operation is less complicated than it seems: starting from the shot on a green sheet, we remove the background of the shot to have only the actor, with a clean edge, which obviously appears against the background of the cartoon. At this point we can reduce the number of colors of the actor, with some precautions to prevent the image from appearing grainy: we want the actor to appear hand-painted, so it is obvious that we cannot have so many shades of color. In addition, we correct the colors to be brighter, except in the shadows. In fact, shadows in cartoons are always represented in gray regardless of the light that forms them, and it is the same thing we will do. An important trick concerns the use of a Gaussian blur to spread the colors and avoid that there may be too sharp edges between one color and another. This will make the result more credible, because otherwise, due to the posterization of the colors, there is a risk of having a “striped” image where there was a gradient in the film. Of course, the nuance must be minimal, because if you exaggerate then you can no longer distinguish anything about the shape of the actor. In the end we can take advantage of the Charcoal effect to draw the outline of the actor, thus giving the illusion that it was drawn in pencil and then painted. But the charcoal effect offers a black and white image: we will then create a copy of the video clip, to apply the charcoal only on this. We will then get two identical clips, one in color and one (above the previous one) in black and white. Using a transition with color multiplication mode we can merge the two images obtaining the colored image but with black edges. In fact, in the multiplication of the color white becomes transparent and black remains black. Obviously, some tests may be needed to find the right dose of charcoal to apply: the contours must be seen, but the black strokes must not cover the actor’s features, especially those of the face. All various aspects, both that of color and that of black edges, can be adjusted using the effects of brightness and contrast. As always, you can see the example video at the following address: https://www.youtube.com/watch?v=FdgGR4vSDEI
A valid shooting method
A cartoon usually has very generic shadows, the scenes always seem lit in the same way. The best way to achieve this is, as Duccio suggested in Boris, to dismantle everything. You can use a diffused light throughout the room, perhaps using reflective panels or a very strong lighthouse pointed on the white ceiling in order to reflect the light uniformly on the whole green screen simulating the Sun. Or, you can film outdoors, better if around noon to not have too many shadows. To help you with perspective, you can print the background design on a transparent sheet (with laser or inkjet printer) and you can position it over the display of your video camera in order to correctly align the actors.
Two clips and a transition
We place a transition between the actor and the background
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Simplify the image
We begin to remove details, so the video will look like a drawing
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Less colors in the shadows
We bring the shadows to gray, and the rest to more vivid colors
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Add the pencil edges
By correctly exploiting the Carbon effect, the edges are drawn on the video
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