Redrawing Motion Lines
This technique was passed on to me from the ever-talented shade. He had an awesome .avi tutorial (with awesome background music), but I can’t find it anywhere. So this mundane tutorial will have to suffice for now.
By ‘motion lines,’ I mean the lines on an object indicating speed and movement.
I imagine you could do this with a mouse if you were really, really talented, but I highly suggest only using this method if you have a graphic tablet. Sorry ^^;
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1) Make a new layer. You should be used to this by now ^^
2) Cover the motion lines with white. Usually, I’ll use the Pen Tool to draw a path around the area, fill with white, and then stroke with black on a higher layer. That way it’ll be sure to have a nice border.
Since her arm kind of had two distinct section, I made a layer for each part.
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3) Lock the transparency on the layer so that you can only make changes to the areas that have already been inked (the white area).

4) Set the Brush Tool to 1 px for every 1000 px that your raw is high. So for the 3000 px high raws, I set the pencil to 3 px. On a 1200 px raw, I’d use a 1 px Brush.
Now comes the fun part. Lower the opacity of the white layer so you can see the direction of the motion lines underneath. Set the brush to black and scribble lightly across that area. Since the layer is locked, you will only color on the pixels that have already been colored white.
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5) Set the opacity back to 100% after a few scribbles and continue coloring it in until you get to the darkness you want. If you make it too dark, you can switch to white, add a few white streaks, and then scribble over those in black again.
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Since the raw had a lot of white near the bottom of her arm, I added a few white lines with the Pen Tool after I was done scribbling the motion lines. I tapered the strokes so that they faded nicely into the motion lines (see this tutorial for an explanation).
Then I prepared the second part of her arm by making a new layer and covering that part in white.
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I did the second section exactly like the first and added extra white streaks near the bottom. This is the final product.
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Here are some other examples:
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Is there any other to do this using a mouse?
Nice method. I don’t have a graphic tablet so I might not be able to use it, but I’ll still try – the result is pretty nice looking.
I usually do that kind of effects by filling the area with black, and then add lots and lots of noise to it so white specks appear, and use a motion blur (or radial, depending on the image ofc). The result isn’t as nice, but it’s decent-looking and very fast to achieve ^^