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The Dehaze slider in Lightroom Classic does exactly what it says by adding or removing atmospheric haze from your photos.
One of the most obvious uses is for editing landscape photos made in hazy or foggy conditions.
But what’s not so obvious is that you can use Dehaze in any number of creative ways. It’s great for adding mood and atmosphere to your photos, something any creative photographer would be interested in.
How does the Dehaze slider work?
According to Adobe, the Dehaze slider is designed to remove atmospheric haze and flare. It analyzes the scatter of light in a photo and works to make distant objects in the photo clearer.
The effect is different and more effective than increasing Contrast or Clarity (which were your only options before Adobe added Dehaze).
One thing to note is that photos tend to become darker when you move the Dehaze slider right. You can compensate by moving the Exposure or Shadows sliders right.
Where is the Dehaze Slider?
The Dehaze slider is one of the Presence sliders located at the bottom of the Basic panel.

You can adjust it by moving the slider or by clicking on the word Dehaze and pressing the ‘-‘ and ‘+’ keys on your keyboard. The keyboard shortcuts move the Dehaze slider in increments of five and let you rapidly move up and down the scale to find the best setting.
You’ll find a second Dehaze slider in the local adjustment settings in the Masks panel, grouped with the Texture and Clarity sliders. The keyboard shortcuts don’t work for this slider.

How to use the Dehaze slider
The best way to show you how to use the Dehaze slider is with examples, so let’s get started.
Dehaze example 1: Adding mood on a rainy day
It’s kind of fun to make landscape photos on a rainy day. Rain and misty conditions add depth to the landscape by obscuring the distant view. Here’s an example that I made in China a few years ago.

Here’s what the photo looks like with Dehaze set to +25. As you can see, it’s easier to see the trees in the distance, but the adjustment has made the photo darker.

I moved the Shadows slider right to brighten the image again.

But in a photo like this atmospheric haze is a good thing because it creates a sense of depth. So, is there a way to be creative with Dehaze? Yes there is – you can move the Dehaze slider left and increase the lack of visibility. Here’s what the photo looks like with Dehaze set to -25 (Shadows slider untouched).

The point is, think about what you want to achieve with photos like these. Does the rain or mist add mood? In that case you can try adding more mood by applying negative dehaze. The last version of this photo is my favorite.
Dehaze example 2: Smoke
Here’s another photo that I made in China. The burning incense sticks in the trough were making lots of smoke. I moved in close to simplify the composition (there were lots of people around and I didn’t want them in the photo). Then I waited until somebody added an incense stick to complete the composition.

You could use Dehaze to cut through the smoke. But personally I think it’s more interesting to add a Linear Gradient, like this:

Then move the Dehaze slider left to increase the haze. Here’s what it looks like with Dehaze set to -20.

Moving Dehaze left makes the photo brighter. If you don’t like the effect move the Exposure slider left to make it darker.
Dehaze example 3: Shoot through glass
I shot the portrait below through scratched glass, which scatters light in a similar way to atmospheric haze.

As you’ve probably guessed, there’s two ways you can go with Dehaze. The first is to move the Dehaze slider right to make the portrait clearer. Here’s the result with Dehaze set to +20. I had to move the Shadows slider right to brighten the image. Here’s the result.

Another option is to move the Dehaze slider left and increase the hazy effect. Here’s the result when I set Dehaze to -20 (I also moved the Shadows slider left to darken the photo). It adds mood and softens the portrait.

But can we get more creative than this? I think we can. Another option is to use Select Subject to make a mask that covers the model, like this:

Then move Dehaze and Shadows left for the dreamy effect we saw earlier.

Create a new Select Subject mask and invert it to make a mask like this:

Then move Dehaze and Shadows right to bring detail back to the background. Here’s the result.

The examples in this article should spark plenty of ideas for using Dehaze creatively in your own photos. The key is to combine it with the new Masks panel tools like Select Subject to see what interesting effects you can create. It’s also important to think about mood, and to see Dehaze as a tool for adding it to your images.
Don’t get too carried away though – less is definitely more when it comes to the Dehaze slider. Keep your adjustments within the -30 to +30 range for a more realistic, natural effect.