AI Sky Replacement in Luminar

Lately, I’ve been using the AI Sky Replacement tool inside Skylum’s Luminar 4.

The idea behind it is to make a scene more engaging by enhancing the sky. It cleverly replaces an uninteresting sky for another of your choosing. Anyone whose done this manually in Photoshop knows it’s a tedious chore to get right.

An image of a harbor entrance light before sky replacement.
The same image after using Luminar’s AI Sky Replacement (click for full size)

Luminar provides several dozen sky images with the tool; all you have to do is try one out. If you don’t like it, try another and keep experimenting until you find one you like.  

In some scenarios, if it doesn’t recognize a sky in your image, the tool becomes disabled. For instance, if you take a picture of your foot, AI Sky Replacement is disabled. But if there is the sky in your image, it works more often than not. I’ve tried cases where I thought it wouldn’t work, and it does.

Here’s an example where Luminar correctly identified the sky through an arch. This surprised me as I thought the software would get confused, but the AI proved me wrong. The photo is of an Instagramer at the Abbey of Montserrat in Catalonia.

Also, there are sliders you can use to tweak the results, but it does the job with or without the sliders. As someone who spends a lot of time looking at details in images, it’s pretty good. 

I won’t go into the arguments of what’s real and what’s fake. I create a lot of images, and I always manipulate them one way or another. I consider photographs straight out of the camera raw material. It is with this resource that I apply post-processing techniques to get the look and tell the story I have in my mind. In that vein, I have no compunction about using software (AI or not) to edit photos. 

Over the years, I’ve taken many thousands of digital images that now sit in a Lightroom library. Less than one percent ever qualify for public consumption. Compositionally, most are just plain bad, but in a few cases, it’s because the sky is too flat.

I’ve started looking at some of these “reject” images with new eyes and asking myself, what if? What if it had a different sky and, perhaps, different lighting? Before I go on, let’s pause here because it’s the second part of this question that I find the most interesting. 

Not only does it (as the name suggests) replace the sky, but it intelligently relights the scene to match the light from the new sky.

Here’s a surreal image of a mountain lake in Oregon after adding a long exposure of the Florida sky? The lighting of the scene below the sky is a result of the AI software.

Think about that for a moment. If your scene was taken in midday, but the sky you’ve chosen as a replacement is from sunset, merely replacing one sky for another might create an unbelievable, if not odd, lighting contrast. As humans, we recognize subtle changes in light, even if we are not always aware of it. But combine a sunset sky with a noontime landscape, and we get a feeling that something is not quite right. 

This is where the AI shines through. Skylums’s software agent works at relighting the non-sky elements with subtle tones of the sky that you selected. If Luminar simply replaced the sky, that would be a cool thing indeed, but Skylum is building upon years of AI experience. They’ve created a machine that combines the expertise of masking (sky replacement) with the techniques of expert toning. That is, given a scene, figure out how to achieve a believable lighting scheme. Of course, the idea of “believability” is subjective, and it depends on your individual preferences. All things considered, it does a pretty good job in a fraction of the time that you could do manually. There are infinite combinations of skies and landscapes, and each result is entirely unique. You could make the argument that it’s not perfect, but then, what or who is? The goal of AI is not perfection, rather accomplishment of things that formerly, only humans could do. In that regard, it’s as good or better and way faster than most humans. 

While we’re on the subject of AI, I just finished Stuart Russell’s book, Human Compatible, Artificial Intelligence and the problem of control.

In it, he explains just how far and fast AI is advancing. Stuart draws the curtain back on the future of our civilization once AI is fully realized. And from the sounds of it, we are much closer to that than most of us wish to believe. I recommend picking it up if you are the least bit interested in what the future holds. 

Skylum’s Luminar is a fascinating tool, and it’s a little uncanny how well of a job it does. But as I’ve come to learn from Russell’s book, this is just the tip of the iceberg, everything is moving in this direction, and we’d all better get used to it. Children born today will never know a world without AI. Any doubts you may have are quickly dispelled the next time you look at your smartphone or ask Google a question. 

So back to the photos, I’ve included some examples of both extreme and subtle applications. In the most extreme case here, the lighting of the ENTIRE scene is changed from daylight to night, as determined by my selection of one of Luminar’s out-of-the-box night skies. I added some additional elements like the light in the lighthouse and some extra toning. But the majority of the scene lighting is done by AI. 

This is how the Oregon coastal scene appears straight out of the camera.
Here, the same image is toned automatically to match the starry sky. (Click for full resolution).

By now, I’ve used it in a lot of different scenarios, some extreme like the previous example, but more often, I use it in subtle ways. Examples of this are where I’m just adding a little bit of texture to a picture where the sky is only a minor background component, not necessarily to be noticed. Here are some examples of that. 

An example of the subtle use of sky replacement on a minor background component of an image
Another example of sky replacement as a minor element to an image.

There’s a lot to like with the combination of replacement and toning, but there’s one more thing that seals it, at least for me. Luminar supplies about thirty skies, from sunrise to the Milkyway galaxy, and everything in-between. So they basically give you enough of a selection for most situations. They also provide addition sky packs from accomplished photographers that you can purchase as plug-ins. But to be frank, I would prefer to use my own skies. And the one feature clinches the deal for me is that Luminar allows you to use your own skies. 

As it happens, I take way too many pictures of the sky. Whenever I’m out shooting landscapes, and I see beautiful clouds, I can’t help but take a picture. By itself, an image of the sky is not that interesting; pretty maybe, but as far as being a complete composition, generally not. 

It’s always been in the back of my mind that one day I’d do something with these images, and that time has come. All those skies I’ve collected can now be used in Luminar AI Sky Replacement. 

I’ve started selecting a few and preparing them for use in the tool. I have morning, daylight, sunrises, and sunsets. I don’t have many night skies, so, for the time being, I’m using nights supplied by Luminar, and truth be told, those are the most fun to try out.

Playing with Luminar’s night skies are perhaps the most fun of all. Here is the silhouette of Mt Tibidabo from Barcelona with one of the out-of-the-box skies supplied by Luminar.

But I’m more of a sunrise and sunset person, so that’s most of what I have. Here’s a snapshot of the ones I’ve prepared so far. 

A snapshot of some of the skies I’ve prepared to be used inside Luminar. Most are from Florida where I live and others are from around the globe.

With my old skies now ready, I’m going back over my archives and revisiting images. Luminar’s AI Sky Replacement is breathing new life into my library. Photos that would never make the cut are being reconsidered with some pleasant results. Anyway, if you’re into post-processing, give it a try. As for me, it’s become a permanent part of my kit. And, like it or not, this is a taste of the future, even as it is upon us now. 

Urban Beach

Here is another image I took on the beach in Barcelona. I photoshopped out most of the people, and believe me; there were a lot.

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Urban Beach
The beach in Barcelona

We stayed at the hotel in one of the tall buildings for a couple of days before a cruise. Walking up and down the beach is entertaining, especially with all the outdoor restaurants and bars. There are so many it’s hard to choose.

beach gallery

Nevertheless, the heat forced us into the shade of a bistro that served icy pitchers of Sangria. And there we sat the rest of the day, savoring the flavors, recovering from jet lag and enjoying the sights and sounds.

Cool W

This is a fashionable hotel at the end of the beach in Barcelona. It’s a cool beach with a cool hotel and cool people walking cool dogs.

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Cool W
The W Hotel on the beach in Barcelona

It’s so cool that I was starting to feel a little self-conscious. But I know that’s silly because the people in Barcelona are not so pretentious. They just have that way about them that seems fashionable to me.

more from Barcelona in the gallery

By the way, this photo is heavily Photoshopped. There were hundreds of people here. But, I picked out the most interesting and turned the rest to sand. If you zoom in, you’ll see some quirkiness. That’s just me and my less-than-cool sense of humor.

Multnomah Falls

No trip to the Portland area is complete without visiting Multnomah Falls. Here is a lie; there was nobody here when I took this shot.

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Multnomah Falls
The most iconic, Multnomah Falls in the Columbia River Gorge

In fact, to get this, I had to elbow my way through layers of Instagrammers holding phones aloft with their backs to the falls. I should have known better, it was July 4th, but I went anyway. I Photoshoped all the people off the bridge except for one. In the end, this edit is not far from the scene I imagined in my head.

see the European gallery

If I did have the place to myself, I would have taken more shots, but I like this shot, so maybe that would have been a waste. Anyhow, when I go back, even if it’s winter, I’ll come early to try my luck again. But it’s all good; I ended up hiking to the top to see even more waterfalls and a lot fewer people. It ended up being an excellent day, for Instagram and me.

Carnon Visit

My recollection of the last time I visited here in Carnon is a little spotty. I seem to remember something about fresh croissants every day.

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Carnon Visit
Along the Mediterranean in Carnon, France

That, and the scenery and the excellent food and, let’s not forget the wine. My memory of the trip is a string of highlights all tied together. I’ve been thinking about it lately because I’ll be heading back in a few months.

More from France in the gallery

I have no agenda other than to get reacquainted with the customs of that region which, as I recall, are quite reasonable. I’ll be taking a lot of pictures, of course.

Big City

When I see a big city, I’m like a deer in the headlights. I look up and can’t stop staring.

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The big city of Miami
The big city of Miami 

I’m fascinated by the perpendicular angles of construction, a million squares, layered and stacked in every direction. It’s a sensory rush that quickens my pulse and speeds up time; a big city high.

more cityscapes in the gallery

Maybe it’s of all the lights, or the mass of humanity, or the scale of it all. Whatever it is, I’m in not much use until I snap out of its initial spell. Perhaps there’s some part of our DNA that attracts us to a hive or colony or tribe. Or maybe, it just all the cool lights.

Street Studies

Here is a shot like the one I posted last week from the central section of old Montpellier. As with that other shot, this is from the day I wandered around taking photos of people walking the narrow streets. I could do that every day if I lived in an area like this, but I don’t so I have to take a lot while I’m there.

Street Studies
A street scene from old Montpellier

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I processed this to make it look like the shot was at night even though it was midday. Transforming it like this is a personal preference of mine, and it creates a slightly different narrative for the image. For me, these types of images are studies in mood, lighting, and effects. I do them to satisfy my curiosity as to how far I can take a picture from its original exposure.

more from Europe

Aside from the processing, what makes a shot like this is the combination of the narrow streets, the curve of the leading line, high walls and the people. That’s a combination that’s generally found only in Europe. That is why I really would like to get back there more often. Maybe I can work something out. <knock on wood>


I imagine the dream world is a mirror; we exist there as fully as we do here. In my waking state, I have only the vaguest remembrance of dreams. A glimpse quickly forgotten.

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There is a veil between the two worlds, sometimes its lifted.

The secret to dreams is knowing they’re dreams; easier said than done. If I knew I was dreaming, would it be a dream? Is the world of dreams a country with arbitrary borders and strange laws? Or is it the other way around?

abstract gallery

There is a veil between the two worlds; sometimes the veil is lifted, and we see through to the other side. We are left with the feeling of something familiar, yet forgotten. The only thing lucid is whatever side of the veil we’re on. And sometimes even that is subjective.

Florida Sun

I used to live in Canada and wondered what it would be like to live in a place like Florida; now that I’ve been here fifteen years I know, hot as hell.

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Florida Sun
This image is from the Venice North Jetty, just south of Sarasota.

It’s called the sunshine state for a reason. The sun is white, hot, and intense; which is why I remain most of the time indoors. I look forward to the few months I can wear a sweatshirt.

Like anything, you adjust with light clothing, hats, and sunglasses. If however, you work outdoors, then you cover up. Outdoor workers cover from head to toe in the most intense heat and humidity imaginable. Think about that.

more sun themes from the gallery

I cannot fathom how the early explorers wearing wool and boots made due. But they did, and now we have A/C, Raybans and Piña Coladas. Thank goodness for that.

Urban Symmetry

This image was taken in central Barcelona from the rooftop of the Grand Central Hotel. At first glance, you’ll notice symmetry in the picture. That’s because I’ve mirrored the image, and then painstakingly altered it so that the equality is incomplete. In effect, I’ve taken something that was perfectly reflected and added randomness.

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Urban Symmetry
This mirrored image creates a sense of confusion on closer inspection

There are plenty of mirrored artifacts, but depending on how you look at it, it might play tricks on you. Our brains quickly suspect its a mirror, and then our eyes begin looking for proof. Depending on where in the image you look, it may not confirm your first impression.

visit abstract gallery

The photo is an exercise in abstraction and deception. It’s a time-consuming exercise to produce, but it’s fun at the same time. My purpose is to hint at one thing while throwing you off the trail and forcing you to figure it out. I hope you don’t mind a little harmless deception in the name of fun.