I was reading in one of the intro posts and Chris was saying that he could use the Osiris Macro pendul instead of a radionics machine. I've only read briefly about sending colors with a pendulum or any other similar activity like this. I use mine in a radithesia way with charts mostly. I really want to learn more about the sending type of action. Is it just the intention and clairity of the operator/dowser that is involved in this or are there other aspects?

You can definitely send colours, rays, planetary energies, etc. to a subject using a pendulum.
You just have to make sure your Dowsing System knows what you are talking about.
For example, when I started, I remember asking if the subject needed violets. My System indicated the person didn't need violets, but did need angstroms in the range that corresponded to the colour violet.
Now I simply ask if the subject needs anything between the angstrom or frequency range of x-y, or I specify "the colour violet".