Tim Grey's newsletter (y'are all subscribed aren't you?) addressed
Brightness vs Exposure recently, thus:
*Today's Question:* Recently you answered a question regarding dodging and
burning in Lightroom. You said to use the Brightness slider on the
Adjustment Brush. I have been using the Exposure slider. Can you explain
why it is preferable to use the Brightness slider? I imagine the
Brightness slider
affects the mid-tones while the Exposureslider changes the black and white
points, but is there a perceptual difference?
This question illustrates one of the great beauties of Lightroom. Assume I
have made dodge/burn adjustments using the Adjustment Brush Exposure slider,
and assume you convince me that the Brightness slider produces better
results. I can go to the image in Lightroom, select the Adjustment Brush,
activate the dodge/burn adjustment, zero the Exposure slider, and adjust
the Brightness slider to the desired effect. I'm done. The whole process
takes less than 15 seconds.*Tim's Answer:* Your assumption about the
difference between Exposure and Brightness in Lightroom is correct. The
Exposure adjustment can be thought of as a white point adjustment, much like
the white point adjustment in Levels or Curves in Photoshop. In effect,
you're "stretching" the tonal range of the image by brightening the white
point, and leaving the black point alone. Naturally this also brightens the
overall image, since essentially all tonal values within the image will be
affected.
The Brightness slider is effectively a midtone adjustment, much like the
middle tone (or gamma) slider in Levels or an anchor point placed at the
middle of the curve in a Curves adjustment in Photoshop. You're brightening
or darkening the overall image without affecting the black point or white
point, with an emphasis on the middle tone values. As such, the
Brightness adjustment
is more appropriate for a dodging and burning effect because it is affecting
the overall midtones without the risk of blowing out highlights or
potentially reducing the brightness of highlights too much, as would be the
case with the Exposure adjustment used for this purpose.
And you're absolutely right about this being a good example of how mistakes
can be so easily fixed in Lightroom. Obviously a non-destructive workflow is
a big part of the Lightroom advantage, though it is also possible to achieve
similar benefits if you focus on a non-destructive layer-based workflow in
Photoshop.
On 29 August 2011 04:50, Moose <olymoose@xxxxxxxxx> wrote:
>
>
> On 8/23/2011 3:27 PM, usher99@xxxxxxx wrote:
>
> > I have read that brightness in PS will not cause clipping,
> > but don't see how that would be if it just adds to the RGB level
> > equally.
>
> You are correct, and whoever wrote such a thing is silly. You can smash an
> image to bits that way. I occasionally use
> Brightness to adjust a temporary layer so that Select=>Highlights or
> Shadows grabs the range I want. The temp layer may
> look terrible, but only exists, briefly, for selection purposes.
--
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