View Full Version : Noise!


flight1
10-21-2003, 06:54 AM
What causes this great amount of noise (or is it grain) in this photo taken of the Grand Canyon at dawn? I used 200 neg. film and scanned with an HP PhotoSmart s20 scanner. Other photos when the lite improved are fine. Thanks for your help. Tom

Doug Nelson
10-21-2003, 09:07 PM
I can't explain why this one turned out noisy and the others didn't but I do know that the noisiest channel is the blue channel, and this has a lot of light blue in it.

roger_ele
10-21-2003, 09:32 PM
If this neg was just a little more transparent, having a little less exposure than the others that might explain it. Underexposure can cause more grain with film. Have a print made from the negative and see if it looks the same ...

boingo82
10-24-2003, 07:08 PM
Originally posted by Doug Nelson
I can't explain why this one turned out noisy and the others didn't but I do know that the noisiest channel is the blue channel, and this has a lot of light blue in it.

jpeg compression recognises that the blue channel is given least importance by human eyes, and that's where it compresses most of the data. Same with the compressors in most digital cameras.