Problem: how to place 10 points on a curve?

Nikolai

I keep fiddling with channel based curves (actually, today I finally got an image where the darn thing worked:-). One thing I realize do I need is to lock the rest of the curve in all channels more often than not.

I remember reading somewhere about a particular PS trick which would allow you to place those anchor point automaticaly and perfectly, without taking a risk of nudging the curve in 9 places out of 10. Unfortunately, I don't remember where I read it and how it's done. It's *not* the ctrl/cmd+shift+click (which allows you to pin all channels at once). It was something different... I googled and found nothing. I asked NAPP and got a "no, and why would anybody need this" type of reply. :dunno

So, my question is: does anybody know/remember how to lock the curve in multiple points (preferably in all chanels, but one will do) quickly and effectivley? :scratch

TIA! :thumb

Nikolai

DIY solution
I haven't found the link I was looking for yet, but at least I came with another idea that kinda fits the bill rather nicely.
Open curves dialog (direct or adjustment layer), switch to one of the channels (does not matter which one as long as it's not a composite one), make sure you're NOT in black/gray/white point mode, move the mouse over to the image and start ctrl/cmd+shit+clicking all over the image, avoiding the area you're planning to fiddle with. Few seconds later you'll get a nice set of anchor points.

The benefit of this approach is lies in the fact that if gives you a very clear picture of where on this or that curve you image actually resides (and I bet you'll be surprised more than once:-).

PamR

As you have found, Cmd/Crtl + Shift click on any area of the image will place 1 control point in each of the color channels. You can do this from the composite curves channel also, btw. No need to be in the individual channels. If you want to place a control point in the same position on the composite channel, just keep the cursor in place, release the Shift key, and click again.

If you want to place a point on the composite channel only, just Cmd/Ctrl click on any area of the image.

Nikolai

PamR wrote:

As you have found, Cmd/Crtl + Shift click on any area of the image will place 1 control point in each of the color channels. You can do this from the composite curves channel also, btw. No need to be in the individual channels. If you want to place a control point in the same position on the composite channel, just keep the cursor in place, release the Shift key, and click again.

If you want to place a point on the composite channel only, just Cmd/Ctrl click on any area of the image.

Thank you Pam!

In addition to my DIY solution, we had exchanged a dozen emails with Pete Bauer from NAPP, and I kinda liked his suggestion: set up whatever anchor points set you want and save it as a preset. Really easy, and with the improved CS3 dialog it's just one click away (and no need to remember extra shortcut:-). It serves slightly different purpose vs my DIY suggestion, but it's also fast and easy to implement.

edgework

Nikolai wrote:

I haven't found the link I was looking for yet, but at least I came with another idea that kinda fits the bill rather nicely.
Open curves dialog (direct or adjustment layer), switch to one of the channels (does not matter which one as long as it's not a composite one), make sure you're NOT in black/gray/white point mode, move the mouse over to the image and start ctrl/cmd+shit+clicking all over the image, avoiding the area you're planning to fiddle with. Few seconds later you'll get a nice set of anchor points.

The benefit of this approach is lies in the fact that if gives you a very clear picture of where on this or that curve you image actually resides (and I bet you'll be surprised more than once:-).

Not necessarily a good idea. The whole point of curves it that they provide a smooth distribution of the color shift. The more tightly you define the surrounding anchor points, the sharper will be the transition between original tones and modified tones until, at the extreme, you will get unwanted posterization, particularly in skin tones which are a complex collection of gradient blends all moving in different directions. You need to let your curve distribute the lead-in and fall-off according to its built-in algorithm. If you find that parts of the curve need to be locked down, usually it's enough to just think in terms of highlight, midtone and shadow. If you're interested in one area, a quick couple of points in the other two ranges are sufficient.

Not to say that multiple anchor points aren't needed for some images, but that should follow a determination based on actual analysis of the various areas of the shot to see where imbalances might lurk.

Nikolai

edgework wrote:

Not necessarily a good idea. ...

Did I ever say it's a panacea?
I thought I specifically outlined the usecase: locking the curves everywhere *except* the area of future changes. If they happen to intersect - you may be working in the wrong space...

gmachen

I used to know how to do this in a quicker step, but I've forgotten. But this longer way will do it:

1) In Curves, click on the freehand draw pencil tool icon.

2) Place the pointer at 0,0 and click.

3) Place the pointer at 100,100 (or 256,256) and shift-click, which draws a diagonal straight line between your two points across the entire range.

4) Click back on the regular bezier icon.

5) Voila! You're now looking at seven more points: on the quartertone, midtone, and threequartertone, plus more points halfway in-between.

Hopefully this will spur someone to remember how to get them on there all in one fell swoop: clicking on the pencil icon, doing [something simpler, a command key combination perhaps], then clicking back on the bezier icon.

Nikolai

gmachen wrote:

I used to know how to do this in a quicker step, but I've forgotten. But this longer way will do it:

1) In Curves, click on the freehand draw pencil tool icon.

2) Place the pointer at 0,0 and click.

3) Place the pointer at 100,100 (or 256,256) and shift-click, which draws a diagonal straight line between your two points across the entire range.

4) Click back on the regular bezier icon.

5) Voila! You're now looking at seven more points: on the quartertone, midtone, and threequartertone, plus more points halfway in-between.

Hopefully this will spur someone to remember how to get them on there all in one fell swoop: clicking on the pencil icon, doing [something simpler, a command key combination perhaps], then clicking back on the bezier icon.

Yes! Free-pencil tool! Damn! Forgot all about it! :bash
Thank you!

edgework

Nikolai wrote:

Did I ever say it's a panacea?
I thought I specifically outlined the usecase: locking the curves everywhere *except* the area of future changes. If they happen to intersect - you may be working in the wrong space...

I never said panacea either. I said it was a bad idea. Here's why:



In the left curve, the area above the adjusted contol point has lost all contrast. It wil show up as a banding artifact and an ungly one at that. Anywhere your curve drops below 45 degrees, your contrast suffers. The trick is to hide it, not call attention to it. The area below the adjustment, while not as severely damaged as the one above, has a much sharper contrast applied to a very narrow range compared with the surrounding tones. As I said, the whole point of curves is to distribute the shifts smoothly across the range. Regardless of the usecase. No matter how specifically outlined.

gmachen

1) edgework is right.

2) Nevertheless, there can be cases where lots o' pinning is useful: special effects, or more frequently & importantly, isolating movements to one color in LAB's A or B channel.

3) I played around in the Curves dialog a little more, and found that it's not necessary to do the excruciatingly precise step #3 in my procedure above. The nine pins can be obtained merely by clicking with the freehand pencil tool once anywhere on the diagonal line, e.g., (31,31), then without moving the mouse shift-clicking again in the same spot. Upon return to the regular bezier icon, there your nine pins are! Much faster this way.

wxwax

Good discussion.

BinaryFx

I personally have only found repeated value in presetting a colour curve lockdown in the LAB colour mode in my work. I made an action that locked down either the red or the green section of the A curve, or either the blue or yellow section of the B curve (including neutrals at the midpoint). Then one could work the "unlocked" half of the curve independently (AB channels not having the same issues as the L channel curve or composite RGB curve etc).

For those that had forgotten about the pencil tool in the curve dialog box, it used to be known as "arbitary map" in the old days of Photoshop where it was popular for solarizing and creating chrome or other wacky effects without the slowness of a filter.


Stephen Marsh
http://members.ozemail.com.au/~binaryfx/

edgework

BinaryFx wrote:

I personally have only found repeated value in presetting a colour curve lockdown in the LAB colour mode in my work. I made an action that locked down either the red or the green section of the A curve, or either the blue or yellow section of the B curve (including neutrals at the midpoint). Then one could work the "unlocked" half of the curve independently (AB channels not having the same issues as the L channel curve or composite RGB curve etc).

For those that had forgotten about the pencil tool in the curve dialog box, it used to be known as "arbitary map" in the old days of Photoshop where it was popular for solarizing and creating chrome or other wacky effects without the slowness of a filter.


Stephen Marsh
http://members.ozemail.com.au/~binaryfx/

lab is a different universe. When I said that locking curves is a bad idea, note I referred to the damaging effects in contrast that can result. Locking the color curves in lab not only will have no effect on contrast, it is, as you have described, essential for anything other than generalized, full spectrum color enhancements.

arodney

gmachen wrote:

I used to know how to do this in a quicker step, but I've forgotten. But this longer way will do it:

1) In Curves, click on the freehand draw pencil tool icon.

2) Place the pointer at 0,0 and click.

3) Place the pointer at 100,100 (or 256,256) and shift-click, which draws a diagonal straight line between your two points across the entire range.

4) Click back on the regular bezier icon.

5) Voila! You're now looking at seven more points: on the quartertone, midtone, and threequartertone, plus more points halfway in-between.

Hopefully this will spur someone to remember how to get them on there all in one fell swoop: clicking on the pencil icon, doing [something simpler, a command key combination perhaps], then clicking back on the bezier icon.

OR: Click on Pencil tool in Curves. Place at 0/0 and draw a small straight line out (like this: _____). Click on the curve button. All points are automatically placed on the grid for you with exact separation in distance.

Control Tab to move the current active point foward (add shift, backwards).

Shift tab select a point adds multiple points to the selection. Then you use arrow keys to move them.

But we still don't have the really great parametric curves like Lightroom!

Nikolai

Andrew,

arodney wrote:

OR: Click on Pencil tool in Curves. Place at 0/0 and draw a small straight line out (like this: _____). Click on the curve button. All points are automatically placed on the grid for you with exact separation in distance.

Yep, that too:-)

arodney wrote:

But we still don't have the really great parametric curves like Lightroom!

Sorry, we do. In ACR4 (which works on raw, jpeg and tiff now).
However, I'm really struggling with it, point curve is soo much easier....

arodney

Nikolai wrote:

Yep, that too:-)


Sorry, we do. In ACR4 (which works on raw, jpeg and tiff now).
However, I'm really struggling with it, point curve is soo much easier....

Yup but like LR, its not an ideal environment for editing gamma encoded images, better for linear encoded raws. I also think moving from Photoshop to ACR is a kludge (here, LR gets it right, you have the same interface for both). I think ACR should be a raw converter and stick to that. And why just JPEG and Tiff but not PSD? Its messy.

Nikolai

arodney wrote:

Yup but like LR, its not an ideal environment for editing gamma encoded images, better for linear encoded raws. I also think moving from Photoshop to ACR is a kludge (here, LR gets it right, you have the same interface for both). I think ACR should be a raw converter and stick to that. And why just JPEG and Tiff but not PSD? Its messy.

Yes, I agree, it would be nice if ACR panels would simply make it to the Bridge... In essence, if LR didn't use the dreaded database and import/export...

As to the psd - ACR only works with the "flat" files. No layer support (only overlay). And that's a huge difference.