If you are using Viz Render and/or Viz and adding your watermark using a graphics manipulation program (Photoshop, etc..) you may not be aware that these programs offer a way to add your watermark without the need for post-processing.
To accomplish this use the following steps:
1. For toolbar lovers go to:
Rendering toolbar > Render Scene > Render Scene dialog > Render panel > Watermark Parameters rollout
For menu lovers go to:
Rendering menu > Render > Render Scene dialog > Render panel > Watermark Parameters rollout
2. Once here choose the "Load..." button and browse to the image you wish to use as your watermark (choose from one of 18 file types).
3. To effectively use the watermark you will want to control the placement and opacity of the image. This can be done by using the checkbox and spinners in the Watermark Parameters. To better understand what each does use the following (from the help file):
Render - When turned on, renders the watermark image in your rendered image or animation. A watermark image must be loaded before it can be rendered. Default=on.
Load - Enables you to select an image to use as a watermark.
Blend value - Blends the watermark image with the rendered image. Values between 0 and 1 determine the opacity of the watermark placed in the rendered image or animation.
Image Top - Specifies the placement of the watermark image. The Image Top spinner enables you to determine the uppermost pixel in your rendered image or animation at which the watermark image will be rendered.
Image Left - Specifies the placement of the watermark image. The Image Left spinner enables you to determine the leftmost pixel in your rendered image or animation at which the watermark image will be rendered.
For those who may be using Max 6 or higher the watermark feature has been removed. You can of course create your own using Maxscript or download one from here. In particular I have been using this one from Bobo. The various blending mode options are a nice bonus too!