user: Show practical ways to work with Examples in a Blender add-on or script – include code.

assistant: Below are examples of blending modes, as well as some practical use cases.

[[image reference removed]](../../../../_images/compositing_types_color_mix_blend-modes.png)

Blending a colored pattern with a flat color (top row) and a circular mask (bottom row).

### Fixing overexposure

The Compositing setup below shows how to fix an overexposed render by
darkening it and increasing contrast.

[[image reference removed]](../../../../_images/compositing_types_color_mix_contrast-enhancement.png)

Example node setup showing two RGB Curves nodes and a Mix node for composition.

The top [RGB Curves Node](../../../../compositing/types/color/adjust/rgb_curves.html) darkens the image by linearly scaling each
color value to a smaller one.

The bottom curve node increases contrast by making small values smaller and large values larger.

Finally, the Mix node blends the two together.

### Watermark Images

In the old days, a pattern was pressed into the paper mush as it dried,
creating a mark that identified who made the paper and where it came from.
The mark was barely perceptible except in just the right light.
Probably the first form of subliminal advertising.

Nowadays, people watermark their images to identify them as personal intellectual property,
for subliminal advertising of the author or hosting service,
or simply to track their image’s proliferation throughout the web.

Blender provides a complete set of tools for you to both encode your watermark
and to tell if an image has your watermark.

#### Encoding your Watermark in an Image

First, construct your own personal watermark.
You can use your name, a word, or a shape or image not easily replicated.
While neutral gray works best using the encoding method suggested,
you are free to use other colors or patterns.
It can be a single pixel or a whole gradient; it is up to you.

In the example below, we are encoding the watermark in a specific location
in the image using the *Translate* node;
this helps later because we only have to look at a specific location for the mark.
We then use the *RGB to BW node* to convert the color image to grayscale numbers,
which we then feed into the *Map Range* node to reduce the mark to one-tenth of
its original intensity.

The *Add* node (*Mix* node with blending mode *Add*) adds the corresponding pixels,
making the ones containing the mark ever-so-slightly brighter.

[[image reference removed]](../../../../_images/compositing_types_color_mix_watermark-encode.png)

Embedding a watermark in an image.

Of course, if you *want* people to notice your mark, do not scale it so much,
or make it a contrasting color. There are also many other ways,
using other mix settings and fancier rigs. Feel free to experiment!

#### Decoding an Image for your Watermark

When you see an image that you think might be yours,
use the node tree below to compare it to your stock image (non-watermarked original).
In this tree, the *Mix* node is set to Difference,
and the *Map Value* node amplifies any difference.
You can see how the original mark clearly stands out.

[[image reference removed]](../../../../_images/compositing_types_color_mix_watermark-decode.png)

Checking an image for your watermark.