If you like doing holiday cards, scrapbooking and crafts, you may want to draw a curving satin ribbon. Or use a ribbon shape as a banner for lettering on a flyer. This article shows how to render a satin ribbon in colored pencils.
Choose a color for your ribbon. My example will be green, so it's suitable for the holidays. I used Prismacolor PC909 Grass Green. Draw a swooping line with S-curves at either end for step one, using the main color of your ribbon. If you want it to have a contrasting edge, like a red edge on a green ribbon, use the contrast color for this line.
Using your ruler, draw a straight line down from the outside edges of each curve, exactly the width you want your ribbon. I used a one inch line for this ribbon. Don't draw the lower edge till these lines are in place. Ignore the ends, we're going to treat them differently. With two curves, there are four places to draw these vertical lines. These are where the ribbon changes direction.
Drawing the bottom outline is tricky. Mark some reference points lightly in pencil as you go, moving your ruler along the ribbon. Use as many as you need to map out where the lower edge of the ribbon goes. With more practice, you'll need fewer reference marks. Make them lighter than you plan to draw the outline, so that they vanish into it when you draw the outline. The more of these you use, the more accurate your drawing will be. On my scan, I digitally marked my reference dots in bright red so you can see what I did. My actual drawing has very faint reference dots.
Connect the dots. Draw the line lightly at first to get it accurate, then go over it to make a strong outline. Now it's starting to look three dimensional!
Finishing and shading your ribbon. Use shading strokes that parallel the outside lines. The shading is more graphic than exact, try to shade only from where the verticals are for the darkest shadows. A satiny look is created by doing the shading strokes parallel to the edge curves. Press lighter at the end of your strokes and let them feather off, using a blunt pencil for the shading. Finish the ends by drawing a vee shape between the end dots, forking the end of the ribbon.
You can add another layer or two of coloring to the shading, using lighter shades of the same color. A bright light green would look good shading off toward the white highlights. Leave a broad white or light space in the center curve if you want to use this as a banner shape for lettering -- just expand the center of the design for banner headings.
Use a grid ruler. That way you can line up the grid lines with the bottom or top of your page to orient verticals perfectly, with very little effort. Drawing the edges with silver or gold metallic pencil is great on a holiday card, so is drawing a line over the edging with a glitter pen or a line of glue and then shake some glitter on it.
If you use metallic or glitter edges on your ribbon, don't go over the verticals in the outline with glitter. Just the curving top and bottom edges. Sketch the ribbon lightly in pencil before drawing it if you plan to put a name or other lettering on it. Sketch in the lettering too, because you may need to make it wider to fit the words. If you use contrasting, metallic or glitter edges, be sure to cover all the light areas in the ribbon with very light shading. You may want to do a second outline in the main color just inside the top and bottom edges.