I've recently run into a problem when rendering a V4 character against an empty background, just doing tests on her right now, don't need an environment yet. Using 4.8 Pro, the City Limits workspace and a viewport with the blue background, or Hollywood Blvd. In the viewport, my background is empty except for that grid pattern representing the ground/floor and the Hollywood Blvd blue environment. But why when rendering the image of my character does the background go completely black? That's not what I see in the viewport image until I hit Render. I prefer the blue environment, which I used to be able to get, but for whatever reason, that's changed. And no, I haven't made any recent updates to DS or changed anything. That I'm Aware Of. So how do I get my blue background back for test renders?

Window-->Panes-->Environment-->Type:Backdrop

Yes I know that. But how to get my original Hollywood Boulevard blue background back instead of the pitch black background in the actual render is what I need to know.

The image will go black if you save to a format without a transparency channel/alpha channel. If you save to PNG or Tiff you will get a transparent background. You won't get the viewport colour (which can be set in Window>Style>Customise Style) - it's backdrop, if set, or transparency/black, if no backdrop is set.

OK, thanks Richard. I later decided to just take a picture with camera & zoom lens of a featureless, clear blue sky and use that as my background for when I want that color. I have been using the .bmp format for rendering files. By transparent background, what do you mean exactly, just plain white or that white & grey checkered pattern? Anyway, plain white is what I got with one setting while using .tif .

The white and grey chequerboard is the on-screen preview since a flat colour might get confused with part of the image (it's the same effect as Photoshop uses). When saved as a tiff or png file (both of which should be a bit smaller than the bmp, without actually losing any data) you will either literally see through the image in those areas to whatever is behind or you will get a flat colour that probably depends on the viewer used. When opened in an editor you will get a partially transparent image or you will get your render on black with a strange border and the alpha channel will be available as a saved selection that can be used to float the image, allowing the insertion of a new backdrop or further image layers.

What Richard said.

Basically a transparent background is so that you can insert your character or other CG object into another image.

This is an example of a technique used by Hollywood and other professional photographers. For example in the chase scene in the Indiana Jones and the Crystal Skull movie, many of the scenes in the amazon used a render as the backdrop, and a render with a transparent background as the image foreground and the live actors in between the layers.

OK, thanks for that info guys.