Thursday, October 11, 2007

Noise And Grain




Don't know if this is of any use to anyone but this morning was printing a picture and noted that in darkening the sky, the noise in the digital image increased (it was a shot on a 10D). I experimented with ways to reduce the noise and settled on gaussian blur 8 pixels wide (which is a huge amount of blur), applied to a duplicate layer, black masked then painted into in varying amounts considerably less than 100% - at 100% screen size there was noticeable blurring of cloud edges but in the print the grain nicely disappeared.

The advantage over using something like noise ninja was I was able to apply it to the exact degree and precise place I wanted it. Using a smaller radius for the blur just made the noise uglier without hiding it.

Here's examples of before and after. Click on the images for true 100% inspection.

2 comments:

Anonymous said...

George,
Try Noiseware Pro. I've found it the best for my use. You might like it.
http://www.imagenomic.com/nwpg.aspx
Brooks

doug said...

If you use Lightroom, you can try converting to B&W using this trick:

http://lightroom-news.com/2007/08/24/tips-for-better-black-and-white-conversions/

From the link:
"The main advantage of using this method is that you can usually achieve smoother looking tones and dark, contrasty skies that are almost completely noise-free"