Jantar Mantar Star Trail Sky Replacement
Photo Processing,  Software

Testing Sky Replacements on a Variety of Photographs – Adobe Photoshop CC 2021 vs Luminar

Luminar 4 by Skylum Software was the first of the major photo editing programs to automate sky replacements.  They did an excellent job with this feature, easily allowing skies to be replaced in landscape images.

With the release of Photoshop CC 2021, Adobe released their own tool to automate sky replacements.  So, which one is better?

I decided to test both the Photoshop and Luminar Sky Replacement software on a variety of different image types:

Topaz Labs
  • Regular landscapes with trees, buildings, etc.
  • Night skies
  • Birds in Flight

Below are my results.  I’ll also give you the advantages of each software at the end of the blog.

Old Mill Sky Replacement - Photoshop CC 2021
Old Mill Sky Replacement – Photoshop CC 2021

Landscapes – Rock Mill

Both Luminar and Photoshop did quite well with replacing the sky on this photograph of Rock Mill.  Both did a good job blending the horizon and also did well in differentiating the leaves from the skies.  I ended up doing no masking on either the Photoshop or Luminar image. 

Old Mill Sky Replacement - Luminar
Old Mill Sky Replacement – Luminar

I was also able to easily match the landscape with the new sky.  This process was a bit more automated in Luminar with their Relight Scene slider.  Photoshop has foreground lighting and color adjustment slides.  However,  when you click OK on the Sky Replacement window in Photoshop, it will create several layers in a layer group where you have access to all the tools in Photoshop to adjust the layers.

Photoshop Sky Replacement Layers Group
Photoshop Sky Replacement Layers Group

Close up of the the Trees with No Masking

Old Mill Sky Replacement Close Up - Photoshop
Old Mill Sky Replacement Close Up – Photoshop
Old Mill Sky Replacement Close Up - Luminar 4
Old Mill Sky Replacement Close Up – Luminar 4

Night Sky Replacement – Adding Star Trails

The next test was replacing the sky in a photograph I took at Jantar Mantar.  Jantar Mantar is an ancient astronomical observatory located in Jaipur, Rajasthan, India.  What a great place to swap in a night sky.

Star Trail Sky Replacement - Photoshop CC 2021
Star Trail Sky Replacement – Photoshop CC 2021

Photoshop did a good job with the blending of the sky with the stairs and stone structures in the image.  I had a little bit of masking to do on the image, but overall I thought photoshop did really well.

Star Trail Sky Replacement - Luminar 4
Star Trail Sky Replacement – Luminar 4

Luminar, on the other hand, didn’t fare so well with blending the sky and foreground.  I adjusted both the Horizon Position and Horizon Blending sliders for quite a while to no avail.  This would have required a substantial amount of masking, so I didn’t bother going any further.

The other advantage Photoshop had for this image was that I was able to scale and reposition the sky.  This allowed me to position the center of the star trails at the top of the stairs.  These are two features that are not available in Luminar at this time.

Birds in Flight – Seagull

Seagull Sky Replacement - Photoshop
Seagull Sky Replacement – Photoshop

I do a lot of bird photography and many times you get a great photograph of a bird with a dull boring sky.  So, I thought I’d see how Luminar and Photoshop fared in automatically replacing the sky on birds in flight photographs.

Seagull Sky Replacement - Luminar 4
Seagull Sky Replacement – Luminar 4

Both Luminar and Photoshop did pretty well replacing the sky on the seagull photograph.

Seagull Sky Replacement Close Up - Photoshop
Seagull Sky Replacement Close Up – Photoshop

I did find that Photoshop replaced some of the wing tip with blue sky, but this was easily taken care of with masking.

Seagull Sky Replacement Close Up Luminar
Seagull Sky Replacement Close Up Luminar

With Luminar, after the replacement there was some strange noise artifacts around the wings.  This could be taken care of with Topaz DeNoise and a layer mask but more work overall than Photoshop.

Here are the advantages of each software:

Photoshop CC 2021

  • Allows you to scale and reposition the sky.
  • If you have an Adobe Creative Cloud subscription, you get the update for free.  You don’t need to buy another software license.
  • Photoshop did a much better job on night sky photographs.
  • Photoshop creates a group of layers to give you additional power in masking and editing the sky replacement

Luminar

  • While both products allow you to use your own images, Luminar lets you select your own skies without importing them into the software.  In Photoshop, you need to import your own skies but you can nicely organize them into folders.
  • In Luminar, it was easier to relight the foreground to match the sky with only a single slider. 

Both Luminar and Photoshop have really good automated Sky Replacement features which are much easier and faster than manually replacing the sky. Overall, I think Photoshop gives you more flexibility and power while Luminar might be a little easier to use.

But the battle of Sky Replacement software is not over.  Skylum Software announced Luminar AI with advanced Sky Replacement that add a feature for sky reflections in water.

Written by Martin Belan

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