Grey fringes

[John Mitchell]

Just wondering, can anyone suggest a method for getting rid of the grey patches and bands that are often left behind in images after purple fringing has been corrected? The grey stuff can look pretty ugly sometimes, especially against a blue sky.

 

QC doesn't seem to have a problem with these unavoidable (?) grey-coloured areas. Or do they?

[Sultanpepa]

I'm guessing they'd class it as a processing artifact but unless extremely prominent may overlook it. Where the drawn line is none of us can be sure unfortunately. 

[John Mitchell]

Right, I'd call the grey areas "processing artifacts" as well. Have never had any QC problems (touch wood) with them, but it would be great to know if there is some way of minimizing the effect. Nothing I've tried has worked.

[Betty LaRue]

This works for hard edges against a blue or bright sky. Buildings, etc.

I use the clone tool, set it on about 50-70 % opacity, might play with opacity to see what works best. Sample the color right next to the grey at the top of your subject. (Or bottom) Use a small hard brush, maybe 80% hard. Put the edge of the brush to edge of subject where it will cover the gray. Click next to your building or whatever at the top where you clone sampled, then holding down the shift key click at the bottom of where you need it. It should sample the color next to the brush automatically as it goes down to bottom click and fade or intensify as needed as the color changes.

If you are left with an obvious hard outside line, then use a small soft brush to repeat the process at the edge of the hard line which helps feather it out. Check at 100%. If you've messed it up, just go back in your history panel.

 

This sounds complicated, but in reality it doesn't take long at all. One click, -clone sample, 2nd click over grey exactly horizontal and abutting your sample, 3rd click to the bottom holding down shift. You can shift click up a side wall and turn a corner over a roof pretty quick starting the process at the bottom.

 

My lenses seldom have purple fringing, and if it crops up, that line is usually thin and I don't bother with it. Once in a while, I do the above. I've never had a fail for obvious touch up, so I must be doing it right.

My Nikon kit seemed to have had more purple fringing than my Fuji kit.

[John Mitchell]

This works for hard edges against a blue or bright sky. Buildings, etc.

I use the clone tool, set it on about 50-70 % opacity, might play with opacity to see what works best. Sample the color right next to the grey at the top of your subject. (Or bottom) Use a small hard brush, maybe 80% hard. Put the edge of the brush to edge of subject where it will cover the gray. Click next to your building or whatever at the top where you clone sampled, then holding down the shift key click at the bottom of where you need it. It should sample the color next to the brush automatically as it goes down to bottom click and fade or intensify as needed as the color changes.

If you are left with an obvious hard outside line, then use a small soft brush to repeat the process at the edge of the hard line which helps feather it out. Check at 100%. If you've messed it up, just go back in your history panel.

 

This sounds complicated, but in reality it doesn't take long at all. One click, -clone sample, 2nd click over grey exactly horizontal and abutting your sample, 3rd click to the bottom holding down shift. You can shift click up a side wall and turn a corner over a roof pretty quick starting the process at the bottom.

 

My lenses seldom have purple fringing, and if it crops up, that line is usually thin and I don't bother with it. Once in a while, I do the above. I've never had a fail for obvious touch up, so I must be doing it right.

My Nikon kit seemed to have had more purple fringing than my Fuji kit.

 

Thanks very much, Betty. I gave your method a try, and it works surprisingly well. I have experimented with using the clone tool but hadn't thought of using the "shift" key (duh). It makes the procedure a lot easier. As you can tell, I'm not exactly a Photoshop wizard.

 

I don't see purple fringing often with my Sony lenses. The exception is with an "ultra wide angle" converter that I sometimes use. It gives sharp results but much purple fringing to correct.

 

Shall keep practicing your technique.

[Gennadii Rybalov]

Just wondering, can anyone suggest a method for getting rid of the grey patches and bands that are often left behind in images after purple fringing has been corrected? The grey stuff can look pretty ugly sometimes, especially against a blue sky.

 

QC doesn't seem to have a problem with these unavoidable (?) grey-coloured areas. Or do they?

I easily get in Camera RAW

Go to lens correction-Color (the delete checkbox chromatic aberration)-move the sliders

[vpics]

I correct all my purple fringes in the Photoshop raw application with just one click. I have never noticed any banding.

[Matt Ashmore]

I know the problem John.

 

Depending on the image, I might either use clone tool in a manner suggested by Betty or develop several version of the image from lightroom with CA sliders in different places to fix different parts of the image and then add them all together as layers on one image in photoshop. I then use masks to keep the bits if each image where the localised bit of purple fringing is fixed. 

[Phil Crean]

When this happens after using the dropper tool in LR CA Correction I tweak the Purple Hue slider blue end if its against a sky and can often recover the blue in the sky without reintroducing the Purple fringe.

 

Phil

[spacecadet]

I've never been brave enough to submit purple-fringe-corrected images precisely because of the grey residue. I auto-correct CA and if that isn't enough, move on.

[Joe Gaul]

Colour replacement tool in Photoshop after sampling with eye dropper tool. Don't know if Lightroom has this.

[John Mitchell]

Thanks for the ideas. I process my RAW images with DxO OpticsPro -- which does a very job correcting regular CA and purple fringing -- and then I use PS Elements for additional tweaking, resizing, etc.

 

Shall check out some of your suggestions regarding sliders, etc. It sounds as if DxO has similar tools to LR's. I'm finding that Betty's cloning method works well for straight edges, but it is a bit awkward for irregular shapes and hard-to-get-at areas.

 

I have submitted images with the grey fringes in them without any problems, so perhaps QC doesn't consider this an issue. If the grey stuff is visible at the edges of the frame, I usually just crop it out.

[John Mitchell]

I correct all my purple fringes in the Photoshop raw application with just one click. I have never noticed any banding.

 

Do you use any very wide angle lenses?

[John Mitchell]

Just a note to say that I cleaned up an image with grey "residue" using Betty's method (cloning tool plus "shift" key) and it has passed QC. I also made minor white balance and exposure adjustments. The processing didn't take all that long and the results look pretty good IMO. Who knows, the image might even license one day.

 

Thanks again for all the suggestions.

[Betty LaRue]

John, sometimes if my sky is a bit too pale behind a building, I add a layer bringing the lightness down which gives me a bluer sky. Then I brush the effect off the building and everything below the sky. Using the shift key, a hard brush, and black as the foreground, I can clean the dark edges off the building. Love the shift key.

I know, there are other ways to get a bluer sky, and I employ those sometimes.

[vpics]

 

I correct all my purple fringes in the Photoshop raw application with just one click. I have never noticed any banding.

 

 

Do you use any very wide angle lenses?

I use it for all lenses.

[John Mitchell]

 

 

I correct all my purple fringes in the Photoshop raw application with just one click. I have never noticed any banding.

 

Do you use any very wide angle lenses?

I use it for all lenses.

 

 

Actually, I meant do you use ultra wide angle-lenses often in your photography? Wide lenses are usually the main culprits for heavy purple fringing. I seldom see much of it in images taken with other types of lenses, and what there is can usually be easily fixed automatically (one click method) without leaving obvious grey fringing.

[vpics]

My ultra-wide lens is currently broken. :-( i have, however, used it on a fisheye with good results.

[Betty LaRue]

I remember in days gone by before we had the later editions of LR and PS when there used to be long discussions about methods to remove purple fringing. Some of those methods worked, but were mega-pains to do. I know, I did them. Then some of the fixes left their own problems.

I reached a point if it was pretty bad, I just tossed the image if I couldn't crop it out. Usually the backlit tree images with purple all over the leaves.

We've come a long way, baby.

[Keith Burdett]

Colour control points in Nikon capture nx2 are great for selecting the purple and replacing with adjacent sky colour, works well for complex tree branch areas. Also available as a Nik plugin I think. I don't see much purple fringing, I tried to gather lenses that didnt suffer from it although my old 80-200 was pretty bad at wide apertures and it's certainly possible with the 16-35...

[Marianne]

I use both Betty's method and Keith's (using the Nik Viveza filter) depending on the situation. Most of my lenses are good but I have a couple of extra wides and even with good B&W filters I'll sometimes get that miserable fringing. 

 

I'm always amazed out how much purple fringing I see in photos even in places such as the NYTimes. I'm assuming these corrections are like dust spots and not considered "digital alterations" but when I see it in news pix and even in the travel section, it makes me wonder. 

[John Mitchell]

I use both Betty's method and Keith's (using the Nik Viveza filter) depending on the situation. Most of my lenses are good but I have a couple of extra wides and even with good B&W filters I'll sometimes get that miserable fringing. 

 

I'm always amazed out how much purple fringing I see in photos even in places such as the NYTimes. I'm assuming these corrections are like dust spots and not considered "digital alterations" but when I see it in news pix and even in the travel section, it makes me wonder. 

 

IME most newspaper travel sections have never been fussy about technical quality. Also, many of the images illustrating stories were taken by travel writers using inexpensive, point-and shoot cameras (or phones these days).