Selecting sky behind trees (AP)

[LenC]

I am trying to apply the directions of the tutorial Channels: Creating/Storing Selections to the file attached*. I wish to replace the whitish strip of sky along the bottom with blue, and am trying to create a mask that matches it. The tutorial file is 16-bit; mine is 8-bit from a JPEG. As in the tutorial, the blue channel has the highest contrast between the sky and the surroundings. I think I understand the Composite RGBA channels but not the Pixel ones. In any case, I created a greyscale image from the Pixel Blue options and then a Flood Select on a clear area of the white sky strip.  This selection is crudely what I need, but the silhouetted trees are sometimes selected, sometimes not. The tolerance slider seems to have no effect on the areas selected.

 

Bottom line: What do I do to refine the selection? The selection brush refine option is confusing – something seems to be working after painting and releasing (blue progress line), but then other things happen when I click Apply in the refine options window. The selection has improved, but I don’t understand how. And can any of these refine options help out?

 

 

* File includes my unfinished selection. I am using AP 1.4.2 under OS 10.11.5.

Sunset Waves 2.afphoto

[barninga]

if you click on a selection tool like the selection brush, then on the refine button that appears above the image, you can use the refine instruments to improve the selection. painting with the matte brush on the edges that need to be refined you should get a nice result.

[LenC]

Thanks, I have tried that, but results are mixed. After painting (dragging brush) over an area with no selection, a blue progress line appears. I can repeat this. (Is anything happening?) Clicking Apply makes the refine window disappear, and I can see some changes by displaying as a quickmask, but result is disappointing; selection of light area vs. dark trees is incomplete. There are few hints in AP Help as to how changing parameters in the Refine window might help improve the selection. Maybe the tree branches are just too faint for this to work.

[m3photo]

On a high speed train at the moment, with poor Wifi signal so I can't see your file.

The classic suggestion would be copying the image onto another layer, make it black and white and increase the contrast. Then select blacks i.e. the trees and work from there.

[Madame]

I can't do anything with your picture.

It appears to be painted with red, -so I can't try this out: Filter>colour>erase white paper. Then you can put a blue sky layer underneath.

[LenC]

m3photo: Have tried to create a threshold adjustment layer via menu and icon, but no new layer appears (or change in the grayscale layer). Another frustrating odd behavior by this program. Closed AP and reopened: no change. Maybe reboot is needed.

Madame: The red color was because I had used the quickmask (like PS rubylith) option to try to visualize the selection. Pressing Q should return to marquee/ants display. I will try the option you suggested.

[Madame]

Hi. Yes pressing Q got rid of the mask. Thanks.

 

I don't think erase white paper is doing the trick on this picture.

 

Here's what I did:

1. make a selection of the area you want to adjust with the rectangular marquee tool.

2. Do a command J to get the selection on it's own layer.

3. Add a brightness and contrast adjustment layer to the selection layer

4. Adjust the brightness and contrast until you see the sky get blue.

5.Use a brush (dial the hardness to zero) with black and paint  (on the adjustment layer) away the orange/purple colour, but keep the blue.

[evtonic3]

I did a blend layers approach.

[LenC]

Thanks for feedback. Will explore all suggestions this evening and let you know how they work out.

 

m3photo: AP failure to create threshold adjustment layer was solved by rebooting computer.