Sky Replacement With Photoshop 2021 and Luminar 4: How Do They Compare?

Well, Adobe has gone and done it. Sky replacement is now a featured part of the just-released Photoshop 2021. For about a year, Skylum has been the leader in sky replacement with Luminar 4, but the story isn’t that simple anymore.

Adobe first showed off sky replacement at the Adobe Max 2016 conclave. It got, as I remember, much applause and interest. But then, nothing. Now, four years later, Adobe is offering this feature, seemingly playing catch-up with Skylum. 

While sky replacement is still a contentious issue, it can mean a lot to many real estate photographers, wedding photographers who do outside events, and some landscape photographers who find it useful at times. The controversy will always be with us, and that’s a healthy thing, but how does the Adobe offering stand up to Luminar’s popular sky controls? 

That’s just what I wanted to find out, so I took an image that has routinely tripped up Luminar because it had trees with many small branches and leaves. It would be very difficult to do a sky replacement by manually masking in a new sky with all this vegetation, so automation offers hope for an image like this. 

How Do the Two Programs Compare?

Here’s the original image of the location:

And here is a closeup of the trees that can be problematic for auto-masking software:

Luminar has some issues here, and while one can use the Close Gaps control to help, it still has problems filling in between the leaves and the branches. You can see the areas where it is less than perfect:

I tried the same challenge with the new sky replacement feature of Photoshop 2021:

This was much smoother, although again, I had to play with the edge controls in Photoshop to improve things. If I went too far with the edge controls, the sky image itself was altered, which is not a good outcome. 

Here’s a look at the sky controls for Luminar, followed by the Photoshop controls. 

In the Adobe controls, note the options to reposition the sky image at the left of the panel, and the scale control that’s missing from Luminar. Photoshop lets you move the sky image vertically and horizontally. Luminar only allows you to move the sky vertically. It’s just not as flexible. 

Who Is the Best?

Normally, I’d call it a day and declare Photoshop the winner, but it’s not that simple. Both software programs have sliders to spread the new sky color on the landscape, making it a better integration between the original image and the new sky. I found Luminar had a much better option there. I got a far more realistic outcome using the Luminar Relight Scene slider than I did with the Photoshop color adjustment slider. With Photoshop, the effect was subtle or not visible at all. 

On the majority of sky replacement tests I did, both Luminar and Photoshop looked about the same. Both let you import skies from your own library, and both let you flip the skies horizontally. Luminar lets you add atmospheric haze and lets you defocus the sky. Photoshop doesn’t, but because the sky is a separate layer, you can do that with the existing Photoshop tools. The results can look quite good with both programs, but Photoshop has an advantage where the mask has to integrate with a complicated, busy foreground.

Still, I’ve had excellent results with Luminar when I’ve needed it, like this photo in an Arizona ghost town. It’s not perfect around some of the detailed metalwork, but it beats manual masking.

Neither Photoshop nor Luminar do water reflections yet. In both cases, you’ll have to manually insert them into bodies of water by making a new layer and creating a mask. However, Luminar has announced its new Luminar AI update shipping late this year will do sky reflections in water, and that’s a pretty big deal when you need it.

Photoshop sky replacements are done in layers, making it easy to readjust image values. Luminar drops in the sky, and you are left with one layer. If you don’t like what you wind up with, you have to start again with adjustments, although Luminar does allow you to go back and insert a different sky before you save the image. Photoshop does the same. A new sky becomes a new layer, which can be kept or removed. Overall, Photoshop offers more flexibility, while Luminar is striving for simplicity.

Of course, Adobe could add that feature as well, just as Skylum could ship Luminar with more options to reposition skies. 

It’s pretty clear many Photoshop users were clamoring for sky replacement, and Adobe has answered that need. Luminar isn’t standing still either, and Luminar AI, when it ships, could leapfrog Adobe. And both programs will surely evolve from here.

Since Photoshop is subscription-based, it was great to see this feature pop up as part of that plan. Luminar is something you will have to buy, and Luminar AI, which will include a more sophisticated sky replacement feature with water reflections will be another expense for Luminar 4 owners. It’s a justified sore point, and I wish Skylum would have simply updated Luminar 4 with the water reflection feature.

Both programs beat manually masking a new sky in by a long way. I’m impressed with both applications, and I’m hoping Luminar will offer better sky placement tools, and I’d like to see Adobe offer better color-matching and water reflection options.


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