Contrast

[Pehpsi]

G'day. i'm working on some night shots and notice when you add a bit of contrast (.05) it can make the dark areas develop patching and ugly noise type stuff. How can i get a bit of contrast via an alternative method??

I use Aperture.

Cheers.

[ATJ]

I find Levels and Curves do a much better job for increasing contrast. I don't know if Aperture has either.

[Pehpsi]

Thanks, yeah Aperture has Levels, and it's working pretty good! I normally don't use it because it looks pretty advanced, but it's doing the job ok. Now i just gota learn how to use it properly

Cheers.

[ATJ]

Levels are pretty straightforward. They basically stretch the intensity of the pixels. Each pixel is given a score between 0 and 255 based on its brightness. Zero is black and 255 is white. If you set the lower input level to say 20, everything that had a brightness between 20 and 0 is set to black and the pixels above 20 are moved down to stretch them between 0 and 255.

Similarly, if you set the upper input level to say 235, it will set all the pixels between 235 and 255 to white and stretch the rest.

The middle input value sets the gamma and this sets how bright the middle grey will be. A value of 1 is normal. A value below 1 will decrease the brightness of middle grey and stretch everything above. A value above 1 will increase the brightness of middle grey and stretch everything below it.

Note that curves effectively do the same thing, but give you more control over the range of values you modify.

[Pehpsi]

Thanks for all the info mate, appreciate it.

[Matt. K]

There is no way to brighten up the shadow areas without introducing noise. That's the nature of the technology. You can hide it to some extent with noise removal programs but you will lose any fine details there.