[Hannican]

Hey all,

I'm going through some year old photos from back when I shot with my kit lens unfiltered and basically had no clue what I was doing... my shots from Thailand are just drenched with haze!

Anyone know if it's possible to do something quickly to clean that muck up with Photoshop?

Thanks in advance!

-Tim

Why don't you post a couple in this thread and let people play with them for you.

[Reps]

You can try this Lunacore Photoshop Training - Remove a Blue Haze tutorial or do a little bit googling as several good tutorials and hints are available online :-)
Best and happy de-hazing, JR

[netuser]

You can try this Lunacore Photoshop Training - Remove a Blue Haze tutorial or do a little bit googling as several good tutorials and hints are available online :-)
Best and happy de-hazing, JR

Seems really a good Hint.
Thanks

[ismaelg]

I've had some success tightening the levels and increasing contrast. I think that translates into a tighter "S" curve.

Thanks,

[MPrince]

If the haze is uniform throughout the image, click auto levels. If that alters the image's colors, undo it and click auto contrast. That's the fastest and easiest method I know of, but it only works if the haze is uniform.

[EricT]

It depends on what kind of haze you are talking about, some samples might help!
But one of the best techniques is called local contrast enhancement, which is basically just an unsharp mask with settings:
Radius: 40-60
Amount: 0.10-0.20
Threshold: 0

Note: I use GIMP, not Photoshop, so the scales might be different, but the idea is to have a very large radius and a small amount, instead of the other way around which is used for normal sharpening.

Note 2: The speed of the unsharp mask operation is dependent on the radius, so be prepared to wait a minute or two!

[Hannican]

Sorry everyone- I completely forgot that I had posted this! Thanks for the advice all! I've been playing around with that tutorial that you posted Reps, but apparently I have a different version of Photoshop than he does? I have no experience using these layers and such so it's pretty confusing for me, but I'm trying to figure it out!

Here is a sample image that I'm trying to "de-haze". I think the haze is only over the water and the hills on the other side of the harbor. I need to remove that haze and perhaps do some sharpening here- plus add a ton of contrast (I love heavy contrast!)

Anyone want to take a shot at this? I'd really appreciate it! I've got a couple of versions that I've worked on, but I want to see what you guys can come up with.

I appreciate the effort, thanks in advance.

[ismaelg]

I tried with RGB levels and boost contrast a bit. I didn't like the results with individual channel level adjustments.

[Hannican]

Thanks Ismael! I was playing with the RGB too- the individual sliders didn't seem to work all that well...

[EricT]

Here are my quickie attempts. The first uses the technique I mentioned, first unsharp mask with large radius and small amount for
local contrast enhancement, then unsharp mask with small radius and large amount for a bit more detail. I think I used r 40, a 0,2 and r 0,2 a 0,8.
The second one uses tone mapping in addition to the other techniques, which is also a local contrast enhancement technique. It is often used in
HDR, but can also be used for single exposures. Hope this helps! The mountains are still a bit hazy, I guess it would be possible to create a
layer mask just for the mountains and then apply a stronger de-hazing here, but I like the picture with the mountains like this.

[song_hm]

Personally, I would leave the far mountain a bit hazy to look natural. I think EricT did a good job on his second version.

In this version, I obliged to your desire for lots of contrast and sharpening. I used several layer of levels and curves for the foreground, mid, and far ground. A high pass filter layer with Linear Light blend is used for sharpening.

[Hannican]

Jeez you guys these look great! I just wish I understood what you are talking about- I need to do some Photoshop tutorials because I don't understand how to use it AT ALL!

Now I know what to aim for at least =)

[Hannican]

Here's my 2nd attempt- using some of the stuff you guys were talking about... high pass filters with soft blend, layers, etc. I don't get any of this stuff, but I just pushed sliders all around and this is what I came up with... how can I make the mountains sharper?? (Edit: Added all three to compare them side by side... I like #3 best, but I want it just a tad darker, and to keep the details on the right side beach's sand... finding it difficult to get that perfect mix!)

[SWEngineer]

Hi Tim.

...I just wish I understood what you are talking about- I need to do some Photoshop tutorials because I don't understand how to use it AT ALL!

Most PS tutorials don't really help one understand how to use it. Here's my attempt a mini tutorial that hopefully explains what is going on. Try it out and play with it. Hopefully you will start to understand what PS is doing under your direction.

All color images can be treated as the sum of Red, Green, and Blue components [channels]. Photoshop displays the separate RGB component intensities as shades of gray with black = no intensity & white = largest possible.

Step 1. Inspect the RGB channels of your original image. The R & G channels look ok. The B channel shows the problem and explains what the haze is in this case: The background of the image has a B channels that is mushy (globally low contrast, devoid of details), and light gray (lots of blue):


To counter-act this you need to 1. darken the blue channel and 2. increase its contrast &/or 3. add some details. I accomplished 1 and 2 with a Levels adj layer. I set the sliders [input levels] of the "RGB" channel to 14 and 232, stretching the overall histogram to make the darks darker and the lights lighter (increasing overall contrast of all channels). For the B channel only, I set the left slider to 18 (making the darks darker) and center to one to 0.89 (making the midtone grays darker). Since only the background of the image has the haze, I added a very simple gradient mask to "hide" the effect of the Levels layer on the foreground. Now the B channel looks better, but still lacks detail:


To add some detail, I used a masked (same mask from Levels) Channel Mixer layer to put some of the R and G channels (which have lots of detail) into B channel. First I "hid" the Levels layer. Then I set the B channel to 50% B, 38% G, and 16% R. This layer alone fixed a lot of haze problem, but shifts the sky color too much in my opinion. So I altered the mask by selecting the sky region and filling the selected area of the mask with black. After turning the Levels layer back on, I decided the Channel Mixer was too strong, so I "dimmed" its impact by lowering the opacity to 50%. Here's the B channels with just the Channel Mixer adjustment (Levels adj turned off):


Note that all my setting values for Levels, Channel Mixer, Opacity, etc. were obtained by eye (watching the effect on the image). Here is the resulting color image (lowish quality JPG):


I think this is a good amount of hazy reduction. It's a matter of opinion if I went too far or not far enough. Regardless, its easy enough to make the effects stronger or weaker.

Now that the B channel is "repaired", you might consider some sharpening. I don't consider this part of the haze reduction, but I thought it helped the image. First I merged the previous results into a new layer so I could use the PS filters on it. I used the Unsharp Mask filter twice. Once at low amount (11) and large radius (13) to provide "local" contrast enhancement and again at high amount (50%) and small radius (0.7) for small detailed sharpening. This improved the background but it over sharpened the foreground and brighter regions of the mid-ground. I fixed the former by "painting" simple black-to-transparent gradients on the layer mask. I fixed the latter with "Blend If". For beginners, just paint on the mask in the bright mid-ground regions with a soft, low opacity brush. Paint over the oversharp areas repeatedly until the mask is dark enought to fix the problem to your liking.

Here's a screen capture of my Layers palette so you can see the masks I used:


Here's the final result (high quality JPG):


I think this is easy enough to apply to most of your pictures if you just use the masked levels adjustment. You can even copy this adjustment layer from one image to another and customize for each photo with the mask and maybe opacity adjustment. For your keepers, you might want go further than I have here. It won't be "easy" or "fast". But if you understand what needs fixed and a few simple PS tools to make the corrections. It will be moderately quick and easy to turn your keepers into breath-taking images.

Cheers.

-Mark