It is not dissolved silver. The method described above is a very crude way of making ionic silver. You will get at best a 5ppm solution of ionic silver, and the rest will be silver oxide suspended in the solution. That black gunk that collects on the electrode over time is silver oxide.

A colloid is created by using a reducing agent to reduce the silver ions back into nanoparticulate elemental silver. This will cause a color change from clear to yellowish brown. However, lots of silver oxide will also change the color - eventually to brown.