Removing halo aka Jeff Schewe's Blue Edge Fix

[Fred Salamon]

On page 238 of The Digital Negative Jeff Schewe discusses " The Blue Edge Fix "
I have tried to use the method he describes but I must be missing something because I cannot remove the halo between the rock face and the sky.

I have tried using the clone stamp tool set to darken, which was unsuccessful.
Tried various other clone stamp tool modes all were unsuccessful.
I tried selecting the sky and masking, inverting the selection, expanding and contracting the selections, nothing seems to be working.
I would appreciate any help.

[Rand47]

You could try the clone stamp in “lighten” mode, since your blue stripe is darker than the blue sky abutting it.  Trouble with that may be that the “lightness” of the orange rocks may also be “darker” than the blue of the sky.

When I’ve had this issue, and none of the clone stamp “modes” have worked, I’ve duplicated the original and then expanded the sky “downward” on the lower layer by an amount that is slightly larger than the width of the dark blue stripe.  I then select and remove the sky from the upper layer and use the eraser tool on that layer to eliminate the dark blue stripe, leaving the expanded sky to be “behind” the rocks.   It’s a pain in the butt, and time consuming, but it can work well on an image that is worth saving in this way.

Rand

[Chris Kern]

I've had good luck with the Schewe technique, but sometimes it takes a bit of experimenting with the clone stamp options as well as some fiddling with different areas for the clone source.

This is a problem that just begs for an "artificial intelligence" automated solution based on machine-learning.

[Jeffrey Saldinger]

When I have to refine the edge between two areas and want to use the clone tool, I sometimes find it useful to clone in normal mode with a brush I’ve modified into a narrow ellipse (with whatever degree of eccentricity seems optimum) and set with a softness that’s neither 100% hard nor 100% soft (depending on how hard or soft the transition between the two areas is).

As I work, I change the direction of the ellipse as necessary so its long axis is more or less perpendicular to the edge along each segment of the edge that needs working on. I might also in the cloning switch back and forth between the two areas, generally without being counterproductively concerned (where possible) with achieving perfection in keeping the contours exactly as they “really” are (I’m more concerned with making the image look “right” at the size I want to print it).

I sometimes find I need to use a dodge and burn layer (50% gray set to soft light) or curves (one screen, one multiply, each at pretty low opacity and/or subtly painted with low opacity brushes) in order to refine the tonal matches.

On page 239, Schewe acknowledges the tediousness of his method, and I have found my method tedious too -- but it works pretty well.

[tsinsf]

I have found that to use "Darken" mode and the clone stamp successfully, you must be working on a full pixel layer, not on a new empty layer with use all layers selected.

[MattBurt]

Is this a processing artifact? It seems like it probably is. The best method I have found is re-processing the image and not pushing it so hard in post to prevent the halos instead of trying to fix them. I've also seen them from an in-camera HDR which is harder to deal with since it comes like that right from the camera. In some cases I've just given up and moved on.
With a shot like this if the halo is in the sky portion you could probably select the rocks and make them their own layer and then increase the size of that layer by a few pixels so the rock covers the problem area of sky. Might be worth a try.

[leuallen]

I have found that to use "Darken" mode and the clone stamp successfully, you must be working on a full pixel layer, not on a new empty layer with use all layers selected.

I use a blank new layer set to Darken and the clone stamp also set to Darken and it works well. Advantages:

(1) smaller file size
(2) if you clone to heavily you can use a 5% eraser or so to erase gradually to lighten up the area.
(3) you can erase mistakes in a selected area without undoing all the work you have done up to that point.
(4) whole thing looks too dark, reduce opacity.
(5) whole thing looks too light, make a copy. Reduce opacity and erase selected areas till it look good.

Sometimes you have a bright halo at the horizon and have to use a high (10%) clone to reduce it. Even using a small brush you may get a dark line or area above the halo. Use the eraser to remove this keeping away from the halo. This is usually easier than trying to keep the clone only in the halo area. Similar to the technique in LR where when making a selection and even using Auto Mask and the selection keeps running over. Instead of trying to painstakingly stay inside the lines, go sloppy and then hold the Ctrl option to set the current brush to erase, and then go over the selection and ease the overrun. It works much better, Auto Mask much more efficient and you do not have to be as careful.

I do HDR panos at sunrise and always run into this problem. A particular problem is bare trees, the areas inside the tree limbs is often way too light and their usually a noticeable halo around the tree. There is nothing you can do in the processing or taking part. It must be fixed in post. There is a section of landscape with tree that I have photographed many times under different light and using HDR and there is a particular section around the tree which is always way brighter than the sky.

For the problem above where the sky is darker than the foreground and you can't clone using Darken from the sky into the foreground because it will darken the foreground. Clone from the foreground to the sky. Instead of filling in with the sky color, it will use the foreground color.

My pet peeve and PS bug. The icon for "Use the same offset for each stroke" clone option has a mind of its own. It will change modes unannounced without you doing anything. It is as if there is a gremlin in your keyboard that sees that you are using this option off and peevishly turns it on thus confusing you and messing up your work. It has been reported but it is a 'legacy' bug that has been around for so long that they will not fix it. It is like the blend mode bug in the layers panel. When you select a new blend mode, it remains active and you must escape or click you mouse somewhere on the screen before you can use another function. It has been around forever and many complaints have been logged but they will not change it.

Yes this is tedious and time consuming. But it is often the only thing you can do if you want a good image.

[GregoryG]

This is without doubt one of my biggest headaches! I only photograph Natures unseen subtleties. I have been playing around with a number of interpolation algorithms. They have to be adaptive in nature. The trade offs between Edge Halos, Blurring and Aliasing can be a nightmare. Photoshop's bicubic and bicubic sharper algorithms don't seem to work. There is suppose to be a new adaptive software in the in beta stage that will handle the Edge Halo's better, but I can't find it anywhere. It's name is "Smart Edge". It's not Adobe's.
I have been able to handle a large % of my issues when shooting smaller objects by using multiple passive reflectors to get behind the hundreds of little edges.