How to create a chalk effect to drawings in Photoshop

First draw whatever you want.

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Then click on the fx of the layer with the drawing ( i hope the drawing and the background aren't the same layer =)))

Then click outer glow and using the the noise slider to a big value ( 50-100 for best effect) and then play with the other sliders. Always remember to set the color of the glow the same as the line drawing.

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This is another example . Enjoy!

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