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This is my favourite background technique ever! I use it for almost everything, these days. (Almost. It doesn't work very well on canvas...)
Materials needed:
hot press watercolour paper (I use Fabriano Artistico 200lb)
gesso
newspaper
fluid acrylics in a variety of colours
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1. Paint a small patch of gesso onto the watercolour paper. I usually do a 2"x2"square or triangle. Use enough gesso that it won't dry immediately, but don't put it on too thick, either. The good old trial-and-error method will show you how much is too much.
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2. Lay the newspaper over the painted patch, and rub gently to ensure full contact with the gesso. Leave in place for a slow count of 10-15. Again, trial and error will show you how much time you need.
3.Slowly peel back the newspaper. If you've done it right, you will see a mirror-image of the text left behind on the gesso.
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If you've inadvertently left the newspaper on too long, some of the paper may be left adhering to the gesso when you pull the newspaper back. This is not a problem. It absorbs the paint differently than the rest of it, and looks interesting. Remember, there are no mistakes here, only opportunities :)
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4. Repeat the above steps til the entire surface is covered with print/gesso. Remember to rotate the newspaper each time for visual interest. Also, try to use various sizes of fonts (headlines or ads, for example). Pictures usually look interesting too.
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Let it dry for a while (although, if it's still damp in spots when you start painting, that gives an interesting effect too...)
5. Time to get out the paints. For this one, I used pthalo blue (red hue), quinacridone crimson, transparent yellow oxide, burnt umber (light) and iridescent copper light (fine). Also a nice big paint brush.
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Dilute a blob of paint with a lot of water. You want a very translucent coat of paint, so you can still see the newsprinting through it.
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Start painting! Leave plenty of white space on your first coat, so the other colours can glow through.
Blue:
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with crimson:
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and yellow:
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and burnt umber + a light brushing of copper to make it shine:
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and you're done!
If you'd like the ATC at the top of the post, that was created using this background, leave a comment. I'll draw a name in a few days.