What's the deal with Posterization?

[S-Man]

(Read the title in your best Seinfeld voice)
Can anyone give me a quick/easy fix for this stuff? It's really irritating. I've tried using gaussian blur and everything. For some reason it's not blending smoothly. In the pic below, notice the upper part of the image where the gray background shades from light to dark.
Thanks in advance.

P.S. Sorry for the watermark, I just quickly embedded from the client's gallery.

[srwatters]

Is it in the original image at full size or a byproduct of the resize?

I've been using a PS plugin called resize magic and very impressed with the quality of the output. I go from full 39MP images down to 800x600 in one jump with great results.

[Snarfy]

2 things:
First, when you begin processing, set your mode to 16bits from 8.
Second, when gradient banding occurs anyway: select the area with the lasso; feather the edge of the selection; add noise; then gaussian blur the area until the noise fills in the bands.

[S-Man]

Originally Posted by srwatters

Is it in the original image at full size or a byproduct of the resize?

I've been using a PS plugin called resize magic and very impressed with the quality of the output. I go from full 39MP images down to 800x600 in one jump with great results.

It's in the finished image after I've extended my gray seamless to the edges of the frame. Not the best way I know but I've found when working with four, 9-ft. is not quite wide enough and my ceilings are only 8-ft.
So the gradient fail happens when I paint in the extra seamless.

Here's a similar shot before processing. I have to make due with what I have.
But the posterization isn't there in the RAW or original JPEG.

[S-Man]

Originally Posted by Snarfy

2 things:
First, when you begin processing, set your mode to 16bits from 8.
Second, when gradient banding occurs anyway: select the area with the lasso; feather the edge of the selection; add noise; then gaussian blur the area until the noise fills in the bands.

Wow really? I'll have to try that. Sounds kind of extensive. Thanks.

[Snarfy]

It's actually very simple when using flat backgrounds. Feel free to PM me if you need more specific tips on it.

btw, it's known as color banding or gradient banding, not posterization. Posterization is an illustrative process.

[S-Man]

Thanks for the clarification :)