HSB Color Mode

Got an interesting technique, or a question about how to solve a particular problem? You've come to the right place!
-default
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Postby -default » Tue Jan 11, 2011 7:28 pm

Once again, a great idea.  Somehow the curve looks more interesting when stretched out horizontally.

sjordan93436
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Postby sjordan93436 » Sat Jan 22, 2011 5:25 pm

I did a couple of simplistic test images.  I took three swatches from CM (flesh, sky, and greens).  I copied and boosted in CM the S of HSB. 

Column 1 original
Column 2 plus 10 S of HSB
Column 3 plus 20 S of HSB
Column 4 plus saturation of Saturation adjustment PS
Column 5 Lab color boost 1.5

I have one copy with RGB numbers.  One with HSB numbers.

Consider this a learning exercise for me. 

Interesting differences.  Not all saturation systems are equal.  HSB keeps the H and B constant.  In this instance, it kept the dominant color at the same RGB value and reduced the others.  (If one color stays the same and the two others are reduced, why does brightness or luminance stay the same)

PS saturation not in favor with experts.  (For me, I ignore it because it has never helped.)  It increases the dominant color. 

LAB color boost shifted the hue of the "sky".  The R value was substantially reduced. 
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-default
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Postby -default » Sun Jan 23, 2011 3:57 am

Thanks for a great set of questions and observations.  Here's my quick response to your question about brightness staying the same when the channel values change, and a couple of things that might also be of interest.

HSB brightness is defined as the max value of the three RGB channels, expressed as a percentage.  So for example, RGB(0,0,255), RGB(255,255,0), and RGB(255,255,255) are all the same 100% brightness, even though to the eye they are vastly different. 

The various color spaces do indeed handle saturation increases differently, since the representation of colors as channel values determines what can be done mathematically.

A couple of other points:

Curvemeister has an option to use Lab for the hue clock.  You may want to experiment with it, but the main reason I seldom use it is that pure colors will not necessarily point to their correct letter on the hue clock.  By default, pure red will point straight up for both HSB and Lab.  You can adjust this, or even reverse the direction of the hue clock by specifying a negative hue clock offset.

HSB's saturation curve is probably the most useful feature of that color space, since it allows bumping color in less saturated objects, without affecting objects that already have plenty of color.

The Brightness curve of HSB is very similar to the composite RGB curve, with the interesting difference that dark and light objects behave slightly differently between the two.

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Postby leeharper_admin » Mon Jan 24, 2011 12:30 pm

HSB's saturation curve is probably the most useful feature of that color space, since it allows bumping color in less saturated objects, without affecting objects that already have plenty of color.


The Vibrance slider in Adobe Camera Raw (and many other Raw Conversion utilities) and Photoshop does much the same job - with the additional benefit of its partial protection of skin tones.

From my point-of-view, the Hue curve remains the most interesting; although as has been mentioned, it is/will be difficult to take advantage of until such a time as the curve is presented horizontally, rather than diagonally - I'm hopeful that to do so would not be very difficult to code (there could perhaps be an option within the Settings window for users who prefer the diagonal UI for the Hue curve, if anyone would be likely to protest the change).

Thank you Steve and Mike for the great information. :)

Lee.

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Postby leeharper_admin » Tue Jan 25, 2011 5:36 pm

Hi everyone :)

I discovered a color correction application app today with quite a nice HSB curves user interface (see attached); the app is called Color Finesse.

The Color Finesse UI features horizontal curves, and backgrounds that make adjustments more intuitive. I think that I prefer the style of the Apple Color UI that I linked to in a previous post - but I'm interested to know what everyone else likes. The aspect of this UI that I'm not keen on is how colorful the backgrounds are (I prefer monochrome interfaces - they are less distracting when I'm correcting); a compromise would be for the curve backgrounds to appear monochrome until the user mouses onto the UI (at which point they could light up).

Just food for thought...

All best,
Lee.
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ggroess
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Postby ggroess » Tue Jan 25, 2011 9:52 pm

Very similar to the Hue screen in Dynamic Photo HDR.

Greg

leeharper_admin
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Postby leeharper_admin » Tue Jan 25, 2011 10:20 pm

Do you have Dynamic Photo HDR? I've been meaning to try it; the 3D Sky filter looks really interesting...

Which style interface do you prefer? The Color Finesse/Dynamic Photo HDR UI, or the Apple Color interface:

S0252_secCurve.png
Apple Color

They both help make the HSB curves more intuitive - but which would be the best way to go?

Cheers,
Lee.

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Postby ggroess » Wed Jan 26, 2011 1:49 am

Lee download the trial and give it a run before you buy.
I did not look at it too hard after learning the PPW workflow I got more out of my images as they are...

Greg

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Postby sjordan93436 » Wed Jan 26, 2011 4:31 am

Even as a novice, I would find the interface of colors distracting.  I assume that Mike could label the X axis with Numbers 0-359.  and / or R y G c B m . 

Would that be enough?  Or a rainbow across the top?  Or rainbow throughout?  I think numbers and letters would be adequate.

-default
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Postby -default » Wed Jan 26, 2011 6:19 am

Definitely the horizontal curve for CM4.  Re colored backgrounds, I concur with Lee.  In keeping with this, Curvemiester has always had the option to turn off the colored borders around the curves.


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