Add imperfections to vector graphics / drawings

Question

I'm looking for creative ways to add imperfections or flaws to my vector graphics in order to make them appear more like hand drawn sketches. I'm working with Inkscape so tips that work here are very welcome but I don't want to limit the question to it.

Here are options that I commonly use:

• Actually drawing objects with freehand tools and simplify them to get rid of shaky hands effects when using a mouse to draw.
• Add objects and blur them.
• Use colour gradients or patterns.
• Use textures.

Are there methods to methodically add imperfections? I'm especially looking for "not so straight lines" (freehand tools) and "not uniform colouration" (multiple gradients?) as may be the result of different pressure in real paintings.

Answer 1

• Line vocabulary. General variation in width of any line. Easy with Illustrator's Width Tool
• Line form. Non-precise curves or angles which lead to a more natural feel - far more natural with a drawing tablet than any mouse
• Color variation - gradients, patterns, textures - often added as a secondary fill and blend space or transparency altered
• Never use 100% of any color. In my experience, only ink and a tech pen lay down 100% color. You only get about 95% max color with any other traditional media.
• Specific, planned, imperfections. Draw divots, bumps, holes, etc. Add moles to people or discoloration areas. Flat, steady, objects always lend to a "computer generated" impression. This is where Pixar and ILM are getting better. They've learned to add imperfections intentionally.

Answer 2

About not so straight lines in Inkscape:

I made a triangle and modified it in different ways. The first is with fine control, the later ones are made with filters which might suit your needs but you can't influence the result locally - only modify the filter yourself/build your own/combine multiples of them.

In the first line there is a too perfect rectangle. I used the calligraphy tool to overwrite it with smaller width (20) and tremble and totter set to 25%. Since I use the german version, the names I use will rarely fit, and unfortunately the menus are sorted alphabetically, so I can't navigate you through the menus. This produces a line with many, many nodes. Switching to node view and hitting Ctrl + L will reduce the number of nodes. Then I marked rectangular areas and removed nodes (- Button) from the lines, but not the corners. In the last step moved and deleted individual nodes. This can lead to very scatchy impressions. It's much work to do but with fine control.

There are some filters which do a similar job. You should try them out.

I created an triangle first, just the outline. Modified contour to path. Then applied the filters. But I don't have a good overview over all the filters, I don't use them often. For the color effects you might find there solutions too, but this is beyond my knowledge.

Answer 3

In Adobe Illustrator you can use Effect > Distort & Transform > Roughen with some subtle settings to give a rougher, less clean edge to shapes/lines.

Answer 4

In Inkscape 0.91: Select Object. Then: Filters >> Distort >> Roughen...

I recomment you only change Complexity and Intensity. Both have to be quite low to simulate varaitions in line caused by hands. Maybe also Variation.