Local adjustments not as effective as global adjustments?

(Greg) #1

I am very grateful for - and pleased with - the ongoing development of local adjustment tools in PhotoLab. As I’ve started to use them more, I’ve noticed that local adjustments to highlights, exposure, etc. don’t have as great an effect as the same adjustment made in the global pallettes. A common example for me is blown highlights in a stained-glass window. A global adjustment to highlights recovers the coloring in the stained glass easily, but dulls the rest of the image. A local adjustment with a mask on the windows (usually an auto mask) often isn’t sufficient for the desired effect. Is something wrong here? Is there a way to get a stronger application of the desired local adjustments? Thank you for your guidance.

1 Like
(Jim) #2

Masks are additive. Simply place another on top the first.

(Greg) #3

Yes, but that isn’t always simple or even feasible. Are local adjustments supposed to be less effective? And does it depend on the type of mask? Hoping someone can answer these questions with certainty. Thank you!

(Greg) #4

@sgospodarenko, can you or one of your colleagues offer any comment on my questions? Thanks.

(Mark) #5

One of the things that has often been mentioned here, and complained about, is that the global highlights slider covers a much greater tonal range then highlight sliders from other software, and affects too much of the midtones. Perhaps the range of the local adjustment highlights slider is more limited and that is why you are seeing a difference. In local adjustments try adjusting the midtone slider along with the highlight slider to see if that gets you closer to what you want.

Mark

(Greg) #6

Thank you, Mark. I know what you’re referring to, but it doesn’t apply to this situation. I’m trying to reduce the extreme highlights locally in various parts of my images where they are blown out. Lowering the local highlights 100% still doesn’t go far enough, whereas lowering them globally just a bit easily gets the result I want where I want it - but ruins the rest of the image (not because midtones are lowered, too, but because I don’t want the highlights lowered globally). Lowering the local midtones doesn’t help at all for this situation. I’ve tried. I’ve also tried lowering local exposure, etc. The problem isn’t tonal range - it’s magnitude. The difference between the magnitude of global adjustments and the magnitude of local adjustments is huge.

(Mark) #7

I don’t recall ever having similar difficulties, but I understand what you are saying.

Mark

(Jim Scott) #8

I rarely use local adjustments in their current state due to the poor masking controls.

But I found your posts intriguing so I thought to given it a go…

Top to Bottom: Original, Global, Local
Highlight control set to -100 for both Global & Local.

(Greg) #9

Ah - thanks very much. It seems the problem isn’t quite what I thought it was! It’s not just the use of global highlight adjustment vs. local highlight adjustment. It’s when both are used together in the same image: the results can be erratic. I’ve discovered that after applying a local highlight adjustment, adjusting the highlights globally has no effect on the masked area, but does affect the rest of the image - making the masked area more weakly-adjusted than it should be. Or after applying the global adjustment, adding a local adjustment could be producing inconsistent results.

This is easily demonstrated if you have several identical objects in an image with blown highlights. Use a local mask to reduce the highlights in one object to -100. Then set the highlights globally to -100. Now click on Compare while Local adjustments is selected. It’s as if there is no local mask: compare will show no difference at all.

This needs further investigation, and I hope DxO will confirm that it’s a bug.

(Mark) #10

In my experience it’s generally better to apply the global adjustments before applying local adjustments.

Mark

(Mark) #11

It is Interesting how perceptions and expectations vary. I use local adjustments very often, primarily the auto masking. The more I become familiar with them the more I use them, While the feature is far from perfect I find I can use it very effectively. I find them especially useful when I want to retrieve shadow detail without effecting the rest of the image, but I regularly use all the available local adjustment tools to achieve just the look I’m after.

Mark

(Greg) #12

To add a little more info: I located the photo with which I first noticed this problem. For that photo, I raised the highlights globally to +16, boosted the Contrast setting +25 and the Highlights contrast setting +50, and made some other adjustments. Then I created local adjustments using an Auto mask on two stained glass windows with blown highlights and set Highlights to -100. In this case, testing with three virtual copies, I find that (a) the local adjustment never becomes very significant because of the global adjustments and (b) it doesn’t matter if the local adjustment is made first or last - the result is the same.

(Platypus) #13

Tried to reproduce the effect on macOS with a simple comparison with one image taken in Monument Valley, showing a bright but cloudy sky. Local adjustment was made so that the sky was covered completely with the mask.

Example 1: No Correction, Highlights -100 -> jpeg export (global adj.)
Example 2: No Correction, Gradient with Highlights -100 -> jpeg export (local adj.)

I get no discernible difference in the adjusted sky area with this simple test. No need to post the resulting images, because subtle differences - if they existed - could not be seen anyway. I might take the output to Photoshop and subtract one from the other in order to see the difference. Just not right now. Maybe someone else could run such a test?