Affinity Photo: how to remove a coloured haze?

[barninga]

hello all,

I have problems in removing a coloured haze from photographs. AP's Haze Removal tool works well for landscape photography, where haze is usually grey-ish, but I found it ineffective when the haze is coloured.

I happen to shoot at live concerts, where wide aperture is often mandatory due to light conditions: this apparently amplifies the interaction between the artificial smoke and the spotlights, often resulting in a sort of coloured glaze throughout the image. Under these conditions, the Haze Removal tool has no or little effect.

The only way I found to clear this haze, at least partially, is to make it as white as possible by applying curves and white balance adjustments, then merging visible layers, then applying the haze removal tool, and finally applying the curves and white balance control again, but with opposite settings.

Could anyone suggest a simpler (and possibly more effective) workflow?

Thank you

stefano

[carl123]

8 minutes ago, barninga said:

Could anyone suggest a simpler (and possibly more effective) workflow?

An example image or two may help

[barninga]

@carl123

you're right, thank you for your reply.

please find the image attached below. my goal is to remove, at least partially, the blue haze. The haze removal tool is ineffective, since the haze is not grey/white (I think).

for this image, if I apply a curve adjustment lowering the blue channel midtone value, I obtain a darker image where part of the haze is gone. If I further apply a wb adjustment, experimenting with both warmth and tint, the colours get altered, but I can make the haze white-ish (with some yellow/green cast). At this point, I merge visible and then the haze removal filter does its job. Finally, I have to apply a curves adjustment where I boost the blue midtones, and a wb adjustment with warmth and tint both set in the opposite way, and I obtain an image where the colours are coherent with the source I attached, and the haze is gone.

[barninga]

this is the result, just to clarify

[Old Bruce]

55 minutes ago, barninga said:

... The haze removal tool is ineffective, since the haze is not grey/white (I think).

From your first post I was thinking there was a haze in front of the people/set and you were having problems revealing that. This image shows that you just need to remove some of the blue light. There is no "haze" to remove, no detail to be revealed. it is blue light with absolutely nothing behind it, nothing to be revealed.

I would try using an HSL adjustment layer. Here are a couple of examples, I don't really know what it is you are aiming for. The adjustment layer has a built in mask so you can further refine things.

[barninga]

@Old Bruce

thank you, that's interesting.

but anyway, i'd say that the pic i posted above is a lucky case. what about this one?

The haze is not plain here, but I don't expect to get rid of it at all: in the end, it adds something to the image. I'd be happy to reveal some details in the people.

thank you,

stefano

[user_0815]

Quite challenging. I'd do it in three steps. First reduce the overpowering artificial blue light with a HSL adjustment somewhat.

Then remove the remaining blue cast with a Fill layer in "negate" mode. Fill colour should be the opposite of the unwanted blue (select the colour and then substract 180). Since the blue isn't in the blacks, exclude them via blend ranges.

Lastly, remove haze with the levels adjustment by pulling up the blacks. Adjust the overal brightness wiht the gamma slider. 

 

 

[barninga]

@user_0815 thank you for your reply.

the result you obtained is not exactly what I'd want, since the image has now a greenish cast. I downloaded it and tried to turn it to its original tones but i didn't succeed.

however the "negate" idea sounds promising and is definitely worth some experimenting, which I'll do as soon as I have a bit of spare time.

thank you

stefano

 

[Old Bruce]

30 minutes ago, barninga said:

The haze is not plain here, but I don't expect to get rid of it at all: in the end, it adds something to the image. I'd be happy to reveal some details in the people.

You say haze, I say plumes of smoke. Semantics aside I do agree that the smoke does add to the image. Look at increasing the exposure to get more detail in the people. Although When I say increase the exposure I do mean at the time of taking the photo.

Stage lighting is for the attendees, not photographers. This sort of photography is extremely difficult. The only honest advice I have is; try working with Black and White instead of colour.

[barninga]

@Old Bruce well english is not my native language, so I sometimes lack the precise words to express a concept, I apologize.

And, since this is the kind of photography I do all the time, I perfectly understand what you mean. I happened to switch to bw more than once, but in this particular case, colour was mandatory, and increasing the exposure, you know, means a longer shutter, or higher iso, or faster aperture. There are limitations, since modifying any of these three parameters brings consequences

I found that closing the iris of the lens has a very positive impact on images: it retains plumes and gets rid of haze. however, you can't raise the iso beyond a certain value without introducing a noticeable noise, and you can't shoot with a slow shutter for obvious reasons. It's a challenging passion

Thank you for your time and advice

stefano

[Old Bruce]

32 minutes ago, barninga said:

It's a challenging passion

With experience the challenges will become fewer.

[barninga]

5 minutes ago, Old Bruce said:

With experience the challenges will become fewer.

yes. I have been shooting music for more than twenty years now, and in these years I found a solution or a workaround for most of them. I am just addressing some postprocessing opportunities right now.

[user_0815]

Several Light sources are always difficult. I think there is a red or magenta light in front of the singer somewhere. Getting everything perfectly neutral is a nightmare and a lot of work with local adjustments.

Experimenting with blend modes negate, substract and divide can get good results when reducing unwanted colur. 

When it comes to targeting specific colurs only, for example the spot light having a greenish cast, then I would suggest the Selective Colur adjustment. Here I have done that. That green was somewhere between green and cyan so I adjusted both. In the second image I added a very slight 5% white balance to get the lights more neutral and the skin tone to a hue around 12. 

[NotMyFault]

I used the following method:

• seperate the image into 3 greyscale layers from RGB channels (channels panel or channel mixer)
• use haze removal on 3 greyscale layers 
• recombine de-hazed layers into one RGB layer

I placed a rectangular mask on the dehazed layer to allow direct visual comparison 

process can be implemented semi or full automatic. 
works kind of usable but won’t do miracles 

haze rem per channel.afphoto

[stuck]

21 hours ago, barninga said:

you can't raise the iso beyond a certain value without introducing a noticeable noise

Indeed, but as an aside to this topic, the DeepPRIME denoinsing algorithms in DxO PhotoLab do an outstanding job on high ISO RAW files.

 

[NotMyFault]

The main problem is that haze removal targets uniform haze. The haze from stage is different, non-uniform and has too much own texture that hides any texture behind.

In addition, the distance is too short to allow the distance based method to really kick in.

[NotMyFault]

In would try if a polarizing filter may help to remove excessive color (at image capture, not in post).

[barninga]

hey, thank you all for your time and suggestions!

 

@user_0815 the result you achieved is impressive. since the haze looks white, the haze removal filter should be effective on the image you obtained. the drawback here is what you said, that a lot of work is required. I'd like to find a quick method, possibly semi-automatic, that can work on coloured haze like the haze filter works on white haze: a couple of clicks and voila. Anyway, for particular situations, your result is very interesting and useful.

@stuck yes I know DeepPRIME, DxO PhotoLab is the raw developing software of my choice. I use it all the time, I would be lost without it. Their NR algorythms do an excellent job. However, there's a difference in the editing latitude that a raw file offers if taken at iso 4000 or iso 8000, so I always try to keep my iso setting as low as possible.

@NotMyFault What you say about the non-uniformity of the haze is true, but not all the shots show this kind of feature. Most of the times it appears to be quite uniform. I never thought about using a polarizer, I'll take it into consideration. Not sure about its effectiveness though, as polarizers deal with polarized light (mainly, reflected light), while haze is diffused light and could be polarized in all directions, thus passing through a polarizer... In additions LED spots light could be polarized per se (I don't know), so a polarizer filter could darken the spotlights. I don't know, I shall experiment around. Interesting.
That said, applying the haze removal filter to each single RGB channels is truly a brilliant idea. In a greyscale image, the haze is grey! I am currenlty looking at the file you posted and it seems you really did the trick. I  am not searching for miracles, but just for a quick method to clean up hazed images a bit in order to recover some detail, and this seems to really work! I will apply it to some difficult images I have and see the results. Very promising!

 

Yesterday night I achieved some interesting result with this simple method:

1) duplicate the image layer

2) on the new layer, apply the Blur->Average filter

3) change the blend mode to Subtract

4) set the Opacity to a suitable value (it looks like 50-70% is fine)

5) if needed, add some Brightness

I just wanted to share this with you.

 

Thank you again for your time and ideas!

stefano

 

[user_0815]

Totally forgot the most obivous thing which is the lens filter (mentioned somewher above). You can "neutralise" the blue or any colour. In this case it makes the blue light rays neutral and leaves the red spotlight coming from the front as you can see in the screen capture. 

For dehaze or clarity I do have two macros which add some adjustment layers, so I don't have to add them manually every time. See screen capture. They're not doing any extreme adjustments but still have quite some effect. If they are any useful for you, I can attach the affinity file.

 

 

[barninga]

10 minutes ago, user_0815 said:

Totally forgot the most obivous thing which is the lens filter (mentioned somewher above). You can "neutralise" the blue or any colour. In this case it makes the blue light rays neutral and leaves the red spotlight coming from the front as you can see in the screen capture. 

For dehaze or clarity I do have two macros which add some adjustment layers, so I don't have to add them manually every time. See screen capture. They're not doing any extreme adjustments but still have quite some effect. If they are any useful for you, I can attach the affinity file.

 

 

 

@user_0815 thank you for this interesting contribution. I tried it and it is actually simple and works well in neutralizing the blue haze. However, I could not find a way to give the blue tone back to the image. Turning the haze colour to white, in my idea, is useful to prepare the image for the haze filer. After eliminating the haze, I would like to go back to the original colours.

[NotMyFault]

I was able to almost completely remove the red haze.

i used the result of per-channel dehaze as starting point.

1. Duplicate layer
2. add live hue mask, and target red. Default range seems a good fit.
3. add a HSL adjustment nested as child to pixel layer
4. use red, and set luminosity to almost zero. 

this reduced not only the color cast (and leave light grey), but fully reveals the texture and structure which was hidden behind the haze.

1. added a vector curve as mask to further restrict adjustment to the people. This is optional.

you can repeat the process for the magenta color cast on right side. There the results were less satisfying.

 

[barninga]

7 minutes ago, NotMyFault said:

I was able to almost completely remove the red haze.

i used the result of per-channel dehaze as starting point.

1. Duplicate layer
2. add live hue mask, and target red. Default range seems a good fit.
3. add a HSL adjustment nested as child to pixel layer
4. use red, and set luminosity to almost zero. 

this reduced not only the color cast (and leave light grey), but fully reveals the texture and structure which was hidden behind the haze.

1. added a vector curve as mask to further restrict adjustment to the people. This is optional.

you can repeat the process for the magenta color cast on right side. There the results were less satisfying.

 

 

 

@NotMyFault 

the hue live mask seems to be a very good finding. Comparing the two images you provided, I maybe prefer the second one (magenta hue mask?), because it reveals quite a lot of detail and leave the smoke plumes almost intact. Personal taste, in the end: I just like them.

What I am learning from this very interesting discussion, is that there are many ways to achieve similar results, starting from the same need. I think I will take note of all the suggestions here, because every single shot is different and maybe there's no way to standardize the process, in a way that the same process is good for any photograph and can be applied the same way.

thank you for contribution.

 

[barninga]

It turns out that the Filters->Astrophotography->RemoveBackground filter also can help. It allows to filter out R, G and B, with the ability to adjust black and grey. It is destructive, so duplicate the pixel layer before applying it.

[nickbatz]

On 3/12/2025 at 11:04 AM, barninga said:

 

 

People have suggested adjustments - and I'd probably reach for brightness/contrast as the first one - but at first glance it seems unlikely that you can process the whole picture with one set of tweaks.

You'll almost certainly have to select and work on individual areas and objects. The guy on the left is darker than the other two, for example, and all their bodies are darker than their heads (because of the lights, of course).

My instinct would be to bring out the details first and then think about changing the color caste.

 

[barninga]

8 hours ago, nickbatz said:

 

People have suggested adjustments - and I'd probably reach for brightness/contrast as the first one - but at first glance it seems unlikely that you can process the whole picture with one set of tweaks.

You'll almost certainly have to select and work on individual areas and objects. The guy on the left is darker than the other two, for example, and all their bodies are darker than their heads (because of the lights, of course).

My instinct would be to bring out the details first and then think about changing the color caste.

 

@nickbatz yes, I get the point, after all it's what I've been doing so far along the years. I opened this topic to explore the availability of a one-click process. My guess was, if there is a haze filter that works well with white/grey haze, there could be a filter (or an automated process) that deals with coloured haze. It turns out that there are some solutions that can be auotmated (for example, dehazing the RGB channels and recompose them into the colour image) and are somehow effective. However, each shot has its own peculiarities and the best result can be achieved only by examining it carefully and applying the method that appears to be the best for that particular pic, or maybe more than one method.

Thank you for your contribution!