Digital BW, The Print

Levels is more intuitive for doing something like expanding your 
tonality, but you are right, if you only do one operation Levels 
should't be any more destructive than any other curve adjustment, BUT 
you will usually follow up a levels adjust with a s-curve for 
contrast which adds a second curve adjust so the sum of your 
destruction is going to be greater.  Better to do everything with one 
curve if possible.  I personally don't like using the "gamma slider" 
for contrast because it is only modifying the middle point on a 3 
point curve while a simple s-curve gives you much more control and 
flexiblity WRT the tonal region where you are actually modifying the 
gamma.  There really aren't really "20 pts of contrast", just the 
local slope of your curve adjustment.  

mark

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "jsinger986" 
<jsphotos@t...> wrote:
> Reading an old thread on levels and grain I had some questions...
> 
> Regarding the difference between levels and curves... aren't they 
doing exactly the 
> same thing, just with different interfaces?  Additionally, curves 
gives you more 
> flexibility than levels (although levels has some features curves 
doesn't)... but, the end 
> result as far as the manipulation that is done to the image is 
identical.  So, one should 
> not be "better" than the other WRT image degradation and grain.
> 
> So if I was to put a quantitative number to the amount of contrast 
I need to add to an 
> image... lets say 20 points of contrast (whatever that may be).  If 
I add 20 points of 
> contrast on an image using levels and 20 points of contrast in 
curves on a copy of the 
> same image, one image isn't going to be less degraded or less 
grainy because I used 
> curves instead of levels.
> 
> Am I correct on this?  This is why I'm not sure I understand why 
people say levels is 
> more destructive and causes more grain than curves.
> 
> Shouldn't the main point be to have as much contrast or do as much 
manipulation in 
> levels or curves, making sure not to clip information unnecessarily?
> 
> Jeff
> http://www.jeffsingerphotography.com