Generative Overlay Textures

This is a quick post on a technique I’ve been incorporating into my sketches lately
for introducing another layer of texture. The basic idea is to draw whatever image
you want, and then throw in some texturing graphics on top with a very low opacity.

Below are some examples of the kind of various textures I’ve got stored in my little
toolkit of generative procedures! Note that the images below show the texturing graphics
as white over black for visibility.

Example 1: Canvas/Denim Texture

The first one is a canvas-like texture I’ve talked about in the past,
and comprises of a hatch pattern drawn with slight variations in stroke and line angle.
The stroke used is a low opacity (approximately 5%) white color.

Example 2: Random Walk + Chaikin Curve

Here I used a single randomly-generated Chaikin curve. I first use a random
walk to generate a polyline that walks across the entire canvas, then smooth it out
using the Chaikin algorithm. I make sure that I
generate curves past the border (a few hundred pixels to all sides of the canvas) so
the edges don’t brighted up too much in comparison to the rest of the image.

Example 3: Restricted Random Walk + Chaikin Curve

Here I use the same random walk but restrict the movement to a fixed step and the
movement directions to the diagonals only. Some areas where the random walk repeats
become slightly brightened, giving it an organic feel.

Example 4: Random Circles

Finally, here’s an example using a few thousand randomly-generated circles of varying
stroke weight and radius:

The above are just a few examples barely scratching the surface of what is possible
of course. This basically works as a completely new layer for creating subtle
generative art using any and every technique used in regular artworks.

Texturing Images

Here is what the result looks like. Below is a sketch I uploaded recently
attempting to recreate the feel of a needlepoint painting. This is the original image
to which we’ll apply our overlay textures.

Here is a version of the above image with the first, canvas-style pattern:

Here is what it looks like with the Chaikin curve:

This is the result with the restricted Chaikin curve (diagonals only):

And finally, with the random circles:

This approach is of course not limited to white only. By giving the overlay texture
a color, we can tint our images since, by using a low opacity, the colors get alpha
blended.

Here is a version with a red overlay:

Here is a version with a green overlay:

And finally, with a blue overlay:

Hope that gives you some ideas! Enjoy!