Re: [darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
This is a good introduction to local contrast: http://www.cambridgeincolour.com/tutorials/local-contrast-enhancement.htm Everything from this point on: this is my understanding, and could easily be wrong - probably is, in parts. I think coarseness of the local contrast is analogous to the radius of USM described above. Contrast and detail are like amount, although I don't know the exact inner workings. I usually use the equalizer. It works like an audio equalizer. Lower frequencies provide a low-resolution view of your image; boosting them will increase local contrast (such as a dark cup will stand out more when placed on a white table cloth). High frequencies are the details; boosting them will sharpen the image (the individual pixels that form e.g. the edge between a stand of fiber in the cloth or a fissure in the cup will stand apart more from their neighbours). Playing with frequencies in between will let you smooth skin without eliminating all detail like pores). Local contrast, sharpen and equalizer always take into consideration the surrounding pixels when determining how a given pixel should be modified. Contrast, tone curve, base curve, zone system just check the values of an individual pixel, without looking at its neighbours. Base curve is in "RGB", in camera colour space, unless I'm mistaken. Each channel is mapped individually, thus colour is affected: applying a steep curve to a pixel with high red value and low blue will increase red and decrease blue, making the colour more saturated (and shifting its hue?). Tone curve operates in Lab, you adjust the L channel and darktable auto-adjusts colour (a and b), unless you tell it you want to do it yourself. Contrast applies a kind of centered tone curve. The zone system tool is also like the tone curve, as far as I know. I haven't had time to watch the videos in the open source photography course, but I guess it covers most of these. Maybe Robert Hutton and others have some useful and free videos, too. Kofa On 19 Sep 2016 16:22, wrote: On Mon, 19 Sep 2016 06:33:31 +0200 KOVÁCS István wrote: >Please read the manual. I did: Much more versatility for contrast and brightness adjustment is offered by the tone curve, levels, and zone system modules and Likewise you may adjust color saturation in a more detailed way with the tone curve, color contrast, and color zones modules and contrast This slider adjusts the image's contrast. brightness This slider adjusts the image's brightness. saturation This slider adjusts the color saturation. Is there some table that compares the various multiple ways of doing the same thing in DT? -- sknahT vyS darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
Re: [darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
On Mon, 19 Sep 2016 09:17:35 -0700 "I. Ivanov" wrote: >Local contrast - if I want to target more specific areas. For >example - the smoother areas to remain smooth but the one with >bigger color change to have some contrast. Interesting. Didn't know that. Is there some page/video that explains it > > For the equalizer - a good start is the presets - for example - build >in preset for clarity. Or build in preset for sharpness or denoise >etc. > The manual is indeed very specific to explain how equalizer >works - in particular the sample pictures. >https://www.darktable.org/usermanual/ch03s04s04.html.php > I've been using the clarity on a regular basis and toning it down to usually to between 30% to 60% >https://dtstyle.net/ has a "skin retouch" style that uses equalizer. >I find it very well done. It also shows some functions that I >wouldn't have expected. I will check it out. Thanks for taking the time -- sknahT vyS darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
Re: [darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
I use normal contrast if I want it to affect the whole image. Local contrast - if I want to target more specific areas. For example - the smoother areas to remain smooth but the one with bigger color change to have some contrast. For the equalizer - a good start is the presets - for example - build in preset for clarity. Or build in preset for sharpness or denoise etc. The manual is indeed very specific to explain how equalizer works - in particular the sample pictures. https://www.darktable.org/usermanual/ch03s04s04.html.php You may want to check also this video - it is done by Robert Hutton https://www.youtube.com/watch?v=zzVXK4eAM5E Equalizer is a very powerful module but it does take time to get used to it. I am at a level to use the presets and apply them with different scale. https://dtstyle.net/ has a "skin retouch" style that uses equalizer. I find it very well done. It also shows some functions that I wouldn't have expected. I recall looking at video (or reading something) comparing equalizer to wavelets plugin in Gimp but I was unable to find it now. Hope this helps, Regards, B On 2016-09-19 07:21 AM, darkta...@911networks.com wrote: On Mon, 19 Sep 2016 06:33:31 +0200 KOVÁCS István wrote: Please read the manual. I did: Much more versatility for contrast and brightness adjustment is offered by the tone curve, levels, and zone system modules and Likewise you may adjust color saturation in a more detailed way with the tone curve, color contrast, and color zones modules and contrast This slider adjusts the image's contrast. brightness This slider adjusts the image's brightness. saturation This slider adjusts the color saturation. Is there some table that compares the various multiple ways of doing the same thing in DT? darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
Re: [darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
On Mon, 19 Sep 2016 06:33:31 +0200 KOVÁCS István wrote: >Please read the manual. I did: Much more versatility for contrast and brightness adjustment is offered by the tone curve, levels, and zone system modules and Likewise you may adjust color saturation in a more detailed way with the tone curve, color contrast, and color zones modules and contrast This slider adjusts the image's contrast. brightness This slider adjusts the image's brightness. saturation This slider adjusts the color saturation. Is there some table that compares the various multiple ways of doing the same thing in DT? -- sknahT vyS darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
Re: [darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
Hi, Contrast from contrast/brightness/saturation is global contrast, a kind of tone-curve adjustment (steeper in the midtones range, flatter in highlights and shadows). Local contrast boosts differences from a local average (a grey spot on black background becomes brighter; the same grey spot on white background becomes darker). Equalizer is a super-adjustable version on local contrast, where you can set the boost for all detail levels at once. Please read the manual. Kofa On 19 Sep 2016 05:38, wrote: Hi, I'm on DT 2.0.6. What the difference between: * local contrast * contrast brightness saturation * clarity/equalizer -- sknahT vyS darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
[darktable-user] local contrast v contrast brightness saturation v clarity/equalizer
Hi, I'm on DT 2.0.6. What the difference between: * local contrast * contrast brightness saturation * clarity/equalizer -- sknahT vyS darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
