Didnt you blokes say to keep A & B the same ?
I don't know if this is the best image to try it on, but this technique has been intriguing me for awhile and I thought I'd try it tonight.
Final after sharpening L only (100/1.0/10)
ps got called in to the hospital in the middle of the night (ultrasound tech) (always taking pictures) and did not get any sleep--
just took some ambien which makes me somewhat looney and really shows when I'm on a forum--had to quit the high school sports forum because I was probably way too embarassing to my kids--
so if I say something that offends, then f-f-forgive me, please--
how are you posting your curves?
trial run curves
ok--is everybody posting to smugmug including graphics files and then on to the forum?
I was using the manage attachments and it was very tedious--
oh well, I will keep at it but right now I need to get back to chapter 4--
thanks for the help--
We can't be much help without that info, and others can't learn from your experience without it.
Tom K. wrote:
I have been reading this thread with great interest. I have a problem that has been driving me up the wall for years.....and it's the fact that I am color blind. I can see colors but I have trouble differentiating between greens, reds, and browns when they are all mixed up in an image. So this LAB method could potentially help me with a "by the numbers" color correction routine........hopefully.
I have been applying the methods in the thread (book is in the mail on it's way as I write this). I have come up with several dramatic improvements to images that have been sitting on my hard drive for a year or two now. The only thing I really have to figure out is the adjustments to the Lightness channel. Channels a and b I am OK with. Creating that final curve in Lightness has been tough.....mainly due to my color blindness.
Anyhow....this thread is the reason I registered with this superb photograph forum. I fell upon it with a good old google search. Here's a split image I did using the basic chapter 1 method.
Tom K. wrote:
.....and it's the fact that I am color blind. I can see colors but I have trouble differentiating between greens, reds, and browns when they are all mixed up in an image. So this LAB method could potentially help me with a "by the numbers" color correction routine........hopefully.
Tom K. wrote:
Creating that final curve in Lightness has been tough.....mainly due to my color blindness.
Tom K. wrote:
Anyhow....this thread is the reason I registered with this superb photograph forum. I fell upon it with a good old google search.
Here is an approach for writing those pesky L curves which may help you. Turn off the visibility of the A and B layers (click on the eyeballs next to them in the layer palette.) Now you are looking at a B&W image. Adjust the L curve to make it look the best you can. And there is a by the numbers approach to that. Select light and dark points in the image, spots where you are willing to blow anything lighter or plug anything darker, respectively. Bring up the L curve and mouse over those points while left-clicking. You'll see a point on the curve representing the luminosity of the image at that point. Drag the endpoints of the curve close to those points (but not all the way there, you'll see why.) Now mouse over the areas of greatest interest in your shot (say a face in a portrait) and consider adding a point to the curve to make it steeper over those areas: perhaps just to the dark side and pulled up a bit or just to the light side and pulled down a bit.
What some concrete examples? Why not post a couple you are having trouble with and I'll show you. Higher resolution is much better and easier, so please provide that if possible.
Not exactly. Your L curve should look more like this:
What does this curve do? The horizontal (x) axis represents input L values and the vertical (y) axis represents output L values. The brightest spot I could find in the picture was in the clouds and it only measured about L=80. By moving the leftmost endpoint of the curve inward by about 15, I specified that anything with L=85 or more should become L=100, i.e., as bright as possible. The darkest area I could find in the original was in the roots of the grass about 1/3 in from the left. It measured about 10. By moving the right endpoint of the curve inward by about 10, I specified that this spot and anything darker than it should be as dark as possible (L=0). This L curve completely loses all contrast for anything lighter than that patch of cloud or darker than that place in the roots. But that's OK, because there is nothing else that light or that dark. That's how I picked those values in the first place. With this curve active, when I mouse over the picture with the left mouse button pushed, the point on the curve moves through the whole range of the steep part. The sky and clouds occupy the upper 1/3, the sand and tops of the grass occupy the midtones, and the roots live in the lower 1/3 of the curve. Now we are using the entire range of luminosity. Should look a lot better. Does it?Full size
By way of making sure I what you're doing here, is this conceptually similar to "pushing in the ends" to the edges of the histogram in a levels adjustment layer?