Community Expert

Question

Select Sky accuracy

Forum|Forum|4 years ago
October 29, 2021
6 replies
2087 views

I was expecting this AI based feature to be able to select a sky accurately, with little need for refinement.

However, having tried it on dozens of images with a clearly defined horizon line, I find that it consistently selects a certain amount of area below the horizon as well. It seems that this unwanted selection goes about the same distance from the horizon in every image, and it follows the horizon line. Which makes me think that it knows where the horizon line is, and still selects below it.

At 100% view, the overlay shows clearly that part of the landscape is selected.

This is also confirmed by editing the selection.

Setting the color overlay to show the unaffected area tells a different story, it indicates (wrongly) that the landscape is unselected, as well as lower parts of the sky.

This makes Select Sky only marginally better than a regular graduated filter.

Both require work with a brush set to Subtract.

Below is the unedited image for reference.

Windows

This topic has been closed for replies.

Todd Shaner

Legend

You need to upload the DNG export file to a file sharing site and then place the share link in a reply here.

R

rjones29@att.net

Participant

I love the new masking tools in Lightroom Classic. But I have a problem that seems to be different but related to this post. I'm getting severe halo or fringing effect when using Select Sky on some of my photos that have a lot of contrast. Here's a zoomed in photo in B&W. It makes the photo unacceptable. I've tried smoothing the edges with tools like the brush, but they don't work. Is the overlap that's mentioned here in one of the posts adjustable under Select Sky that would meld the sky select and subject along their borders alleviate this problem?

R

rjones29@att.net

Participant

Sorry, I attached the wrong file in my previous post. Here is the zoomed-in image.

GoldingD

Legend

On your examples, that Granite will be sneaking into the mask as it has blue, and the lighting is what it is, So, I assume a quick remove mask is Color Range.. Or you could try an intersect using color range, picking blue, just not the blue in the Granite.

Todd Shaner

Legend

The mask overlap into non-sky areas was probably done to minimize demarcation fringing. This can be seen in image files when the shooting lens has visible chromatic abberation (see below bug report). By softening the mask edge these types of mask artifacts are minmized. What might be helpful is to provide a Refine mask control similar to what's availble with the Color Range control.

https://community.adobe.com/t5/camera-raw-bugs/p-lightroom-and-camera-raw-color-range-mask-edge-artifacts/idi-p/12240036

Per Berntsen

Author

Community Expert

The mask overlap into non-sky areas was probably done to minimize demarcation fringing. This can be seen in image files when the shooting lens has visible chromatic abberation (see below bug report). By softening the mask edge these types of mask artifacts are minmized. What might be helpful is to provide a Refine mask control similar to what's availble with the Color Range control.

By @Todd Shaner

Yes, a Refine mask control would be perfect, where you could control the width of the mask edge, as well as other things.

In the example I posted, the mask covers about 250 pixels of the landscape.

JohanElzenga

Community Expert

While I agree that the routines could be improved, I would suggest that you judge a mask by what the adjustment looks like, not by what the mask overlay shows you. The reason is that a little overlap into the landscape below the sky is not necessarily a bad thing. It avoids ugly halos around the edges, for example. It could also make an image look more natural. If you adjust the sky in your image and make it more blue, but leave the top of the rocks completely neutral, then the result may look less natural than if the top of the rock has a very slight blue tint as well. That's because the light on top of the rocks is reflected from the sky and so it actually would be a bit blue if the sky was blue.

I have found that the majority of my sky masks do not need any fine tuning if I look at what the adjustments do. But if I just look at the mask overlay, I would conclude that it definitely needs to be fine tuned.

-- Johan W. Elzenga

JohanElzenga

Community Expert

To illustrate my point:

-- Johan W. Elzenga

GoldingD

Legend

A long but very good vid to watch on the new masking

https://www.youtube.com/watch?v=Y7Fld8eEHsE

Should be fairly easy to clean up that Sky mask

Per Berntsen

Author

Community Expert

I've watched part of the video, seems very good so far.

As for the mask picking up blue from the rocks, it also includes green and brown so I don't think color is the issue here.

I have tried using Color range. and then subtracting using Luminance range, which worked reasonably well, but it tends to leave a thin white line on the horizon. I can get rid of most of the white line, but then too much of the landscape just below the horizon is selected.

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