Pages: [1]   Go Down

Author Topic: B&W filter artifacts?  (Read 699 times)

Mousecop

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 70
B&W filter artifacts?
« on: November 09, 2016, 08:36:47 PM »

Heya, so I've noticed this issue for some time now, and am curious if there's a better way to deal with it.

In some cases, when I try to darken a blue sky in a B&W conversion, some parts of the image seem to develop artifacts. One common instance is with leaves and tree branches. The original image does not appear to have any serious CA.

This is working in Lightroom, using the B&W Mix feature with some custom presets to emulate various types of filters. I've tried SilverFX and the results seem to be about the same. The images obviously use progressively stronger red filtration.

Any thoughts?

Logged

BartvanderWolf

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 6571
Re: B&W filter artifacts?
« Reply #1 on: November 10, 2016, 07:42:08 AM »

Heya, so I've noticed this issue for some time now, and am curious if there's a better way to deal with it.

In some cases, when I try to darken a blue sky in a B&W conversion, some parts of the image seem to develop artifacts. One common instance is with leaves and tree branches. The original image does not appear to have any serious CA.

This is working in Lightroom, using the B&W Mix feature with some custom presets to emulate various types of filters. I've tried SilverFX and the results seem to be about the same. The images obviously use progressively stronger red filtration.

Any thoughts?

Hi,

It looks like a combination of a relatively noisy Red channel (which gets more dominant when using a Red filter in postprocessing), and sharpening. I gave it a quick try in Topaz B&W Effects, but the JPEG artifacts got in the way. If you use a Raw image to begin with, and it is hopefully taken with low ISO, you should be able to do a better job.

If you know in advance that you'll be using a B&W conversion with a Red filter, it's best to do it when taking the actual picture with an optical Red filter, because you'll be able to increase camera exposure and thus relatively reduce shot-noise, and need less of a push in postprocessing.

Cheers,
Bart
Logged
== If you do what you did, you'll get what you got. ==
Pages: [1]   Go Up