ON1 Photo RAW 2022 copies the AI-powered sky swapping technologies in Skylum Luminar and Photoshop, but ON1’s first attempt falls some way short of the mark.
Like the AI-powered sky swapping tools in other programs, ON1 Photo RAW Sky Swap AI uses the power of artificial intelligence to automatically identify and mask skies in outdoor scenes so that you can replace them with different, more attractive or more dramatic alternatives.
This is something that’s always been possible using regular layers and masks, but not necessarily easy – and sky swap tools are definitely aimed at users who want instant results which don’t need much time or technical know-how.
Like other programs ON1 Photo RAW comes with a selection of replacement skies in different categories, but also the option of inserting a sky image of your own.
Replacing a bland sky with something very different requires some additional controls, and ON1’s Sky Swap AI tool has the option to ‘relight’ the foreground to match its colors and tones with the sky, and to add reflections of the new sky in water if needed.
So far so good. But how effective is it, and what are the results like? Here are some images I’ve worked on in ON1 Photo RAW, fully intending to show some examples where it’s worked brilliantly and some where it’s struggled. As it turned out, it struggled with pretty much all of them.
Here’s a quick run through my various Sky Swap AI attempts – and note that some of them were not chosen to be difficult. Quite the contrary. I chose a few that ought to be very easy indeed.
ON1 Photo RAW 2022 Sky Swap AI tests
- How to use the Sky tool
There’s really nothing to it. When you open an image for editing you’ll see there’s a Sky panel. Click this, wait for the AI to do its work, then choose a sky/category from the drop-down menu below. The choice is very good, though there are a few rather lurid, somewhat grainy ones.
- Initial results
OK, so this hasn’t gone quite as planned. The AI masking has hit a problem with the blue sky and masked most of it but not all of it, so there are these blue patches on the right and a rather awkward transition. Worse, the light tones in the building have taken on the gloomy sky tones. The thing is, there is no control over the mask sensitivity or color range – this image’s blue sky cannot be made to mask properly.
- Swapping Sky process
OK, so let’s try another. The sky in this shot is clean and bright but a little dull. Let’s see what Sky Swap AI can do here. Whenever you select the Sky panel, ON1 Photo RAW will take a few moments to do the AI sky recognition. It’s only a few seconds, not minutes.
- Foreground relighting
OK, so I went a bit mad with this just to see if it’s possible to change the whole character of an image with a new sky. This hasn’t gone TOO bad, and a little experimenting with the Shift Edge, Fade Edge and Shift Horizon slides have helped keep the horizon line relatively natural-looking – though at the expense of allowing the sky to creep over the buildings on the skyline. But using the Foreground section to try to match the sky color hasn’t gone great. Even with the Amount and Distance sliders turned up to max, it still looks like what it is – two different images combined.
- Better sky matching
If you try a more sympathetic approach, things work out better. The original shot had a pale and misty sky, and I’ve chosen a replacement sky that’s also pale near the horizon line. The effect looks quite pleasant and quite convincing, but it did mean choosing the ‘right’ sky for the image and not trying to change its character.
- Fine edge masking gone wrong
But if I choose a different, more dramatic sky, the AI masking goes wrong. The Sky Swap AI simply can’t cope with the fine twigs and branches of the trees, leaving obvious edge effects against the darker sky – and the masking controls simply aren’t sophisticated enough to fix this. In this instance (and others) ON1 Photo RAW’s regular image layer, masking and blend mode tools are likely to give you a much better result.
- Soft masking exposed
The fact is, the Sky Swap AI tool creates a pretty soft-edged mask around complex edges. You can tighten it up with the sliders but then you create edge artefacts which are worse. It’s not alone – Photoshop’s Sky Replacement tool uses a similar ‘fudging’ technique. Indeed, if you take a close look at the mask thumbnail for the ON1 Sky Swap AI tool (it’s pretty small, so good luck), you’ll see how soft the AI mask is. This is where Luminar is simply streets ahead.
- Sky Swap AI masking fail
The AI masking does seem to be this tool’s weakness. The first example at the start of this walkthrough had areas of sky that should have been masked but weren’t, and this one has areas of foreground that have been wiped out by the sky and shouldn’t have been. This would not be a difficult image to mask manually – the edges are mostly straight lines – but the AI has got it completely wrong. Note also the obvious soft edge around the left side of the hotel block from the soft mask edge.
ON1 Photo RAW 2022 Sky Swap AI verdict
This feels like a feature that’s been rushed to market for the sake of being able to say it’s there, but just doesn’t work very well. If you choose a ‘sympathetic’ image for the replacement sky it can blend quite well, but if you try to drop in a sky that’s too different in tone or color, the tool’s weaknesses become obvious immediately. Worse, the AI’s sky auto-detection is prone to weird fails, and the masks it creates are soft and create pretty obvious ‘glow’ effects around foreground objects.
Hopefully the Sky Swap AI tool will improve in future versions of ON1 Photo RAW. In the meantime, you might just be better off merging in replacement skies the old-fashioned way, with layers, masks and blend modes.
And don’t let the Sky Swap AI tool put you off ON1 Photo RAW 2022. It’s just one tool in a program that has a lot of strengths and a lot of useful and effective features.
• ON1 Photo RAW 2022 review
• Skylum Luminar AI review
• ON1 Photo RAW tutorials
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