A demonstration of aggressive Imagenomic NoiseWare processing on an ISO 6400 from-camera JPG
from a 50D that can remove almost all noise artifacts including the horizontal "dark-river" streaking.

The noise-processing can be independently controlled for shadow, midtone and highlight areas.

Less aggressive, more realistic processing would leave some of the noise-grain to give an illusion of more detail.

This sample image is part of a 50D Sample Gallery on www.dpreview.com.

The look of a sample D90 ISO 3200 image is more like in-camera point-and-shoot processing.