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d&b and hue/saturation shifts

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  #11  
Old 07-25-2009, 01:15 PM
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igot2pman igot2pman is offline
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Re: d&b and hue/saturation shifts

Sometimes you’re forced to saturate or desaturate with D&B. IF your dodging then your making the colors lighter, therefore less saturated. And if your burning, your making the colors more saturated.

You can also paint on the SL layer with color. Paint with the same color but lighter if you want to dodge. Or paint with the opposite color but darker to burn. I.e. here your would use a light red and dark green.

When working on any layer with D&B, always work at low opacity low fill, unless on a tablet. Like 8/15.

Hope it helps,
-Keven

Last edited by igot2pman; 07-25-2009 at 01:24 PM.
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  #12  
Old 07-25-2009, 03:51 PM
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Re: d&b and hue/saturation shifts

There's been both good and bad advice in this thread. Concentrating on the bad …

Quote:
"Have you tried converting the image to LAB color"
Converting to LAB mode and back, is very destructive to the color in an 8 bit image. Why? look at the A&B channel histograms in LAB - see how narrow they are? In LAB the color information is now held in about 50 to 100 posterised values. When that image goes back to RGB it has to interpolate the color back again. (Dan Margulis lives in a world of his own sadly). In 16 bit you can almost get away with it, but there are better ways…

The same visual result you can do without decimating your file - Luminosity blends, (which USE A VERSION OF LAB ANYWAY) or the very good tip that Der_W gave in the preceding post.
Quote:
"Curves gives you more control but sometimes shaping the right curve for the image can be tricky because a standard center arc does not always get the right brightness or darkness across the image where it needs to be."
That would be advice for people who have no understanding of curves whatsoever. And discourage them to learn the most basic tools

Last edited by Markzebra; 09-13-2009 at 12:17 PM.
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  #13  
Old 07-25-2009, 03:52 PM
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Re: d&b and hue/saturation shifts

Quote:
Originally Posted by Der_W View Post
If you use a grey layer you can also make advantage of the luminosity-mode by creating a new adjustment layer (don't change any of the values) and set its mode to "Luminosity". After that clip the grey layer to this adjustment layer so it will only affect the luminosity (at least that's the theory behind it).
To change quickly between two layers you can use shortcuts as well, [Alt]+[]] for the next layer, [Alt]+[[] for the previous layer.
That seems cumbersome really specially if you are right handed like most you have to lean way over and press 2 keys.. I really like the pressing of the X key with left hand. I already have my waccom program for the option so when I clone I click and spray...
I like the curves layer and it is good that you can change it afterwards.
The only bummer is not being able to click back and forth bewteen the both easily b/c with skin retocuhing you go over the same area and D&B simultaneously.
You never really do one or the other, atleast I do not.

Also I hate changing bewteen LAB and RGB but looks like it is effective by your example.

Snook
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  #14  
Old 07-25-2009, 05:48 PM
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Re: d&b and hue/saturation shifts

Quote:
Originally Posted by snook305
That seems cumbersome really specially if you are right handed like most you have to lean way over and press 2 keys
Snook,

Quote:
Originally Posted by FelixTheCat
Thanks for and ideas for switching fast between both curve sets. If there is.
The shortcut was just refering to his question, I should have made that more clear.

By the way: As I'm using the grey layer I tend to switch between my foreground and background color quite often but I think that's just a matter of own preference.
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  #15  
Old 07-25-2009, 07:11 PM
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Re: d&b and hue/saturation shifts

And you can set two F keys to swap the L and D layer - don't need a modifier combination. This can also be attached to your pen buttons. Most people, would use the pen buttons to scale brushes prior to CS4. Or remove the button altogether if they had a club hand.
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  #16  
Old 07-25-2009, 07:11 PM
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Re: d&b and hue/saturation shifts

OK then let me rephrase for you so it may be clearer.
Any shorter cut than your short cut as I do not find it short?
Hey say that 3 times fast!!
Shorter than pressing X two switch from white to black is going to be hard to beat.
I usually work on 30 meg files in 16 bit so I do not have many problems with color contamination.
Snook
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  #17  
Old 07-26-2009, 11:14 AM
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Re: d&b and hue/saturation shifts

Markzebra, I couldn't let this one pass either. I won't get into all of the ugly equations used to convert data from LAB to RGB color spaces and back and will grant you that there are interpolation errors in process. That said however, the errors are negligable from a practical and perception standpoint. If you take an 8 bit full broad spectrum RGB test image and use the Edit>Convert to Profile to convert from aRGB to LAB and back 5 times you will find very minimal mathematical change with a level of 0 or 1 difference in the R and G channels and up to a level change of 2 or 3 in the B channel. The change is nost visually perceptable. (This assumes a flat image with no layers).
Used appropriately and in the correct position of a work flow the use of LAB is not bad advice. The things you can accomplish there both in efficiency and capability far outweigh the minute change in levels. Moreover those changes are far less destructive that other things which are done to images in conversions of color spaces, sharpening, and many other color adjustments.
In the end, you are moving the image to LAB temporarily to change it in a way that significantly improves how it looks. I think there is a time to get concerned about data alteration and interpolation degradation. However I don't think that making a trip to LAB and back is one of them.
Regards, Murray
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  #18  
Old 07-26-2009, 11:49 AM
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Re: d&b and hue/saturation shifts

The point is Murray, the same visual effect that you have illustrated with your strawberry is achievable by keeping the image in RGB. So WHY convert at all? Any changes to the channels in LAB (especially color channels) and then converting back will be more damaging than taking an unaltered image, and shifting it back and forth. Look at color noise before and after.

Lab does have its uses of course, but in 16 bit. Color (AB) moves in LAB can of course deliver what look like amazing results, but gamut (the intent) has to be very carefully watched indeed. Look at your blown color channels when you get back to RGB. Photoshops RGB mode is the most versatile and contains within it blending math that will allow you to simulate most LAB moves, much more painlessly, still remaining within gamut - this has always been the case.

Last edited by Markzebra; 07-26-2009 at 12:08 PM.
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  #19  
Old 07-26-2009, 01:14 PM
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Re: d&b and hue/saturation shifts

Markzebra, thanks for the reply. In the samples I attached, I deliberately pushed the D&B over the edge to make a point. An 50% overlay on an RGB image distorts the color and very easily / quickly can blow out the channels. Doing the same thing in LAB is much more difficult. The D&B effect is more gradual and you have more contro. I agree with you that curve adjustments set to luminosity blend produce zero damage to the image, however I would challenge you to take the original image using your method and get to the same result in anywhere near the same amount of time / effort. In a time constrained job, LAB is one of a great many tools to help cut the cycle time and still produce quality results.
Things get even better in 16 bit and these days with all of the support for 16 bit in msot programs and s/w tools, there is lttle excuse for most of us not to use it extensively through the workflow.
Regards, Murray
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  #20  
Old 07-26-2009, 01:22 PM
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Re: d&b and hue/saturation shifts

Ok you need to re-read Der-W's post 9, remember there's Linear light and all the other contrast modes to try. Thats more versatile than dodge and burn in LAB. There are many different ways within RGB, obviously some longer than others, to achieve a similar result to that.
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