The promise and difficulty of AI-enhanced editing


A few years ago, an executive at Skylum, a manufacturer of Luminar editing software, said the company is actively hiring hotshot machine learning programmers as part of its efforts to inject AI capabilities into Luminar. For the first time, I got a glimpse of the importance of using AI to set it apart from other photo editing apps. Skylum has released the latest version of its AI-based editor, Luminar Neo.

One of the new features I most wanted to explore is “Relight AI”. This symbolizes what AI technology can do for photo editing. Imagine being able to adjust the lighting of your scene based on the items that the software identifies, add light to the foreground objects, and control the depth of adjustment as if the image was rendered in 3D.

Frankly, I’m not reviewing the entire Luminar Neo, but focusing solely on the Relight AI feature. This app has just been released and in my experience so far it’s still rough and lacks some basic functionality.

Why “rewrite?”

Much of the photo editing we do is relighting, from adjusting the overall exposure of an image to dodging and burning to make certain areas more or less noticeable.

However, one of the core features of AI-based tools is the ability to analyze a photo and determine what is drawn in the photo. If the software knows the content of the image, it can act on that knowledge.

If a person is detected in the foreground but is in the shadow, you can increase the exposure of the person to make it appear as if a strobe or reflector is illuminating the person. This is usually done using selective paint, circular or linear gradients, or complex selections. These methods are often time consuming or too general.

For example, the following photo is not only underexposed, but the tones between the foreground and the background are very similar. You need to shed more light on the subject in the foreground and separate it from the active background.

The exposure and depth of field are not very good here. Jeff Carlson

So I can start with the obvious: brighten people. One option for many apps is to paint the exposure adjustment on the app. In Luminar Neo, you can use the Develop tool to increase the exposure value and use the Mask feature to apply the edits only to the subject.

New photo editing platform Luminar Neo "Rewrite AI" feature
I applied the mask in a few seconds. It takes a few minutes to do it right. Jeff Carlson
New photo editing platform Luminar Neo "Rewrite AI" feature
When creating a mask, you can easily create unwanted halos. Jeff Carlson

Another option is to brighten the bottom half of the image and apply a linear gradient that blends into the top, but it also brightens the ground on the left side of the frame (obviously behind the family). Similarly, I don’t want to illuminate the railing on the right side.

Ideally, I want to be an art director who demands a brighter foreground and makes the software aware of it.

How Relight AI works

You can use the Relight AI tool to control the brightness of areas near and far from the camera. You can also extend the depth of the effect. In this example, increasing the Brightness Near slider actually brightens the family and railings, darkens the background a bit, and smoothes the transition between what Luminar Neo considers to be the foreground and background.

New photo editing platform Luminar Neo "Rewrite AI" feature
An image to which only “Brightness Near” is applied in Relight AI. Jeff Carlson

The photo is already much closer to what I intended and I moved one slider. You can also lower the Brightness Far slider to retract the entire background. The Depth control balances the other two values ​​(returns to depth immediately).

New photo editing platform Luminar Neo "Rewrite AI" feature
The background is darker and more separated from the foreground elements. Jeff Carlson

Depending on how the effect is applied[詳細設定]of[デハロ]Controls can be used to smooth the transition around foreground elements such as human hair. You can also use the Warmth slider to warm or cool near and far areas.

How about a photo without people?

OK, photography with people is important, but it’s also an unmanageable achievement for AI. Humans are treated specially because people found in the foreground are often the subject of a photo. What if the image doesn’t contain people?

In this next example, we want to brighten the foreground while preserving the color of the sky and the silhouette of the building. To exaggerate the effect, ratchet the brightness close to 100 so that Luminar knows where the object is identified.

New photo editing platform Luminar Neo "Rewrite AI" feature
The original image is too dark. Jeff Carlson
New photo editing platform Luminar Neo "Rewrite AI" feature
If you increase “Brightness Near”, you can see that Luminar thinks it is the subject in the foreground. Jeff Carlson

You can see that not only the main building but also the plants in the foreground are lit up. Luminar protected the background sky on the left side of the building and did not touch the farther building on the right side. Therefore, Relight AI clearly detects the prominent shape.

New photo editing platform Luminar Neo "Rewrite AI" feature
Decreasing the Depth value only illuminates the bushes in the foreground. Jeff Carlson
New photo editing platform Luminar Neo "Rewrite AI" feature
Relight AI adjusts the brightness based on the detected shape. In the extreme, halos have also been introduced around the nearest building. Jeff Carlson

If you reduce the depth value, the nearest bush is still illuminated, but the building remains in shadow. Increasing the amount of depth adds an unnatural halo to the main building, but the side buildings still hold up well.

Therefore, the overall Relight AI is not bad. These two images have achieved the main goal. You can quickly and easily adjust the brightness at short and long distances.

Where to struggle

Here we keep a big disclaimer that applies to all photos edited using AI tools. The quality of the effect depends largely on the image itself and what the software can detect in the image.

In this picture of the tree, the software doesn’t know what you’re actually looking at. The bushes and trees on the left and right are about the same distance from the camera, and the rest of the trees recede to that distance. My expectation is that the trees on those sides will be illuminated and the forest will darken as it moves away from the lens.

New photo editing platform Luminar Neo "Rewrite AI" feature
This group of trees does not have a typical depth perspective. Jeff Carlson

However, with dramatic changes to short-range and long-range brightness controls, Relight AI falls into a top-to-bottom gradient because many photos have the foreground at the bottom and the background at the center and top. Back The prominent trees on the left and right do not appear as dark as the other trees, so they appear to be partially recognized, but they still have no effect.

New photo editing platform Luminar Neo "Rewrite AI" feature
When in doubt, Relight AI applies a gradient to simulate foreground and background lighting. Jeff Carlson

Other restrictions

Occasionally, for people, even if you adjust the depth setting, the tool applies a value close to the brightness and sticks to it. For example, in this photo of a person in a sunflower field, darkening the background and illuminating the foreground will balance the image and show the leaves and sunflowers closest to the camera.

New photo editing platform Luminar Neo "Rewrite AI" feature
Original image. Jeff Carlson
New photo editing platform Luminar Neo "Rewrite AI" feature
Relight AI improves the lighting of your subject and knocks down the brightness of the background without any additional editing. Jeff Carlson

If you set the depth to a low value so that the light looks very close to the camera, the flower on the left (the closest object) will be dimmed, but the person’s lighting will remain the same. This tool assumes that the person will be the main subject, regardless of the depth of the image.

New photo editing platform Luminar Neo "Rewrite AI" feature
The lighting of the person is constant even when the depth is set to near zero. Jeff Carlson

Another limitation of this tool is the inability to adjust the masks created by the AI. You can edit the mask for the overall effect of the tool as you did when you painted it manually before, but it only affects the location of the image where the tool’s processing is displayed. The AI ​​cannot help identify which area is at what depth. (This is also related to the discussion I made in the previous column that I don’t know what AI tools detect.)

Lights up in the future

Luminar Neo’s Relight AI feature is bold and works well with little effort to produce good results. That is the point. Computational photography will continue to advance and object recognition will definitely improve in the future.

It’s also important to understand that this is just one tool. In a realistic workflow, you need to use these features and extend them with other tools such as dodge and burn as needed to get the desired results.


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