Levels
divamum
Registered Users Posts: 9,021 Major grins
Question 1:
- what exactly IS "levels" (I can see how moving the slider adjust things, but I'm unclear as to what it's actually doing, particular vs curves and setting a black and white point)
Question 2:
- why does a tweak to levels make a picture seem sharper (I find for minor sharpening, it's doing a better job than the sharpening in LR raw)
I'm googling for information too, but would love to hear from the gurus hear. Thanks in advance! :thumb
- what exactly IS "levels" (I can see how moving the slider adjust things, but I'm unclear as to what it's actually doing, particular vs curves and setting a black and white point)
Question 2:
- why does a tweak to levels make a picture seem sharper (I find for minor sharpening, it's doing a better job than the sharpening in LR raw)
I'm googling for information too, but would love to hear from the gurus hear. Thanks in advance! :thumb
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2. A picture gets sharper because you increased contrast. Sharpening is really a local contrast manipulation. Levels is a different kind of contrast manipulation, but since it does increase contrast it too produces a sharpening effect, just a different one.
To add to the ptevious reply....
The levels graph represents the histogram. Sliding the left control inward will bring up the black point, sliding the right control inward will brighten the highlights. Moving the middle slider left or right will brighten or darken the mid-tones respectively. If you hold the "alt" key while moving the left or right slider it will "warn" you as to the areas in the image that are blown or plugged as you move the sliders. This allows for fine tuning without relying on eyesight. It does NOT sharpen an image. I wouldnt rely on it as a replacement for sharpening.
Read up on the sharpen and mask tool in LR. I used to skip out on LR sharpening altogether and use the high pass method in PSCS3 instead, but now use lightroom to sharpen the majority of my shots. THAT is worth investigating.
Also....the 4 sliders under the curve box in LR will give you much more control than PS's levels.
...and...
If you truely need to set a black and white point the curves tool in PS is your best bet. It can be set perfectly if you use the threshold tool to locate the white and black point first and then assign them using curves. Theres a tute....if I can find it Ill share it!
Jeff
-Need help with Dgrin?; Wedding Photography Resources
-My Website - Blog - Tips for Senior Portraiture
Could this be it?
- Wil
They all involve using the Threshold command in the layers palette to find the appropriate points to choose for your black and white point. Slide the slider to the left for the black pint and the right for the white point . You do not want a colored point - say very dark green - for your black point, and you do not want a specular for your white point.
Mark these to points with the eyedropper so that they are recorded and visible in your info panel. Close out the Threshold layer as it is no longer needed. Open Curves or Layers and use the black eyedropper to click on your chosen black point, and the white eye dropper to click on your chosen white point.
You can also find a gray point, but I find this much less useful for images that do not already possess a real gray point.
(Ideally, you have already preset your black and white point values in the color picker to match values that you can print and recognize with your printer. They should be the darkest point and the lightest point in a 256 step gray scale that you can see distinctly with your printer on your printing paper. For my Epson 3800 that is around 4,4,4 and 250, 250, 250 )
Moderator of the Technique Forum and Finishing School on Dgrin
I've read that tute and used the black/white point method described therein regularly. It's really good. I just haven't used levels at ALL until for some reason I pulled it out and played around with it (can't even remember why, now - maybe part of an action or something that reminded me?)
In any case, I do use all of the tools mentioned, but was actually impressed with the simplicity and efficiency of levels. I haven't mastered curves yet - I tend to use it by trial and error and often get it seriously wrong and have abandon the layer and start all over; I still haven't figured out "by the numbers" (on my to-do list over coming months). The little bullseye tool in LR makes it a bit easier since I can eyeball it, but even so - I never feel confident with it.
Anyway, thanks for the all the added info - great stuff!
PS Jeff, I definitely use the sharpening tool in LR, very much in conjunction with the noise-reduction sliders. I'm developing a reasonably reliable "recipe" of those for my camera's results at different ISO's, so it's turning into a pretty automatic part of my workflow (fwiw I usually have colour NR ALL the way up, luminance about 1/3 to 1/2-way on a well-exposed iso800 shot, and 3/4 or all the way on 1600 shot in dark conditions; not nearly that much if I could expose to the right!). I then have sharpening 1/4-1/2way, with the radius at the default. Sometimes I'll use Rutt's hiloam sharpening instead. And if I really need to tweak it, into CS3 it goes for some hi-pass adjustments. No claim made here for "correct", but it seems to work for me. I'm constantly experimenting, though, which is of course the beauty of LR - tweak to your heart's content until it LOOKS good!!!
Yup....
...and Diva...
Often "after" a levels adjustment you can see that the graph has some areas that are blank and appear as vertical strips in the graph. That is missing data from your file and could appear as "blocking"......er....or "holes" in your dynamic range. Point is....yes it's quick......but can also damage a file.
Jeff
-Need help with Dgrin?; Wedding Photography Resources
-My Website - Blog - Tips for Senior Portraiture
AHA! I've often wondered how to read that graph, and what the gaps-and-spikes meant (I've seen it after other extreme adjustments, ie crazy saturation levels etc etc). Tx, Jeff!!