Use of Mask Layer to Replace Sky

[bobs]

In Photoshop, I have seen demonstrated a very quick and easy method of replacing a bald sky in an image using a mask layer. One of the great things about this method is that if you have a scenic for instance with trees against the sky and the sky peeping through the trees here and there it handles those areas where the sky peeps through very well..
I have attempted to do this in Paint Shop Pro X4 and get almost exactly what I want except that the final result has two faults – the replaced sky part of the final image is in grey scale and the rest of the image is far too dark.
If any one knows how to fix this I would appreciate some help.
Here's what I did.
Start with a scenic with a bald sky and a second image of the sky with some clouds – then:

1 - Open the scenic – label it SCENIC and duplicate it.
2 - Open the sky image – paste it as a new layer into the scenic image, label the new layer SKY
3 – 3 layers are now present from top to bottom – sky, copy of scenic and scenic
4 – Open a mask layer – Layer/New Mask Layer/From Image – in dialog box select the sky image for
source image and use source illumination, click ok – You now have an additional (group) layer
5 – Activate the sky layer and set blending mode to darken.
6 - Select the brush tool with a good size brush, make sure the foreground color is black and paint the
whole image.
That's it. Note that the sky in the finished is grey scale and the rest of the image is too dark.

Any solution?

[df]

4 – Open a mask layer – Layer/New Mask Layer/From Image – in dialog box select the sky image for
source image and use source illumination, click ok – You now have an additional (group) layer

You lost me there. Why is the source of the mask the sky layer? I assume you want the sky to show through, so wouldn't you want to use the scenic or copy of scenic with Invert Mask Data checked to make the overlit part of the sky part of the mask?

5 – Activate the sky layer and set blending mode to darken.

That's pretty effective if you have the mask layer set correctly I must say.

6 - Select the brush tool with a good size brush, make sure the foreground color is black and paint the
whole image.
That's it. Note that the sky in the finished is grey scale and the rest of the image is too dark.

Any solution?

I'd say in step 6 you'll want to make sure that you reselect the mask layer.

A screen shot of what you have (showing the layers palette) would be helpful, but this seems to be tons quicker than what I currently do. Thanks for sharing it.

[bobs]

Dan - Thanks for the quick reply. Doing as you suggested doesn't work as well in that the places where the sky peeps through the trees is not properly handled. Painting with the brush in those areas causes the sky to revert back to the bald sky where the sky peeps through the trees..

[currikid]

Simple use of selection to add new sky to existing image. Select sky to be replaced using Magic Wand and use Shift key to add to selection and then copy new sky and Paste into selection for quick result.
This is quick and simple if you don't have trees or other objects to contend with.

Currikid

[df]

OK so going off your idea, which is a great idea by the way, here's the steps I'd advise.

1) Open Scenic.

_MG_9736 by cabbiinc, on Flickr
2) Copy Scenic, Paste As a New Image (Image 1, rename Scenic Copy), Paste as a New Image again (Image 2).
3) Increase contrast on Image 2 until you get enough definition between ground and sky. (I had to do this to my image since a cloudy day usually yields a less contrasty scene).

Image2 by cabbiinc, on Flickr
4) Open Sky. Right click> Copy.

Sky by cabbiinc, on Flickr
-- the rest of the steps happen on Scenic Copy --
5) On Scenic Copy paste the Sky as a new layer, rename it Sky.
6) With Sky layer selected, Click Layer> New Mask Layer> From Image. Source Image = Image 2. Create Mask From - Source Illumination. You will get the layer, the mask layer, and the Group - Sky in the layers palette.

Mask From Image by cabbiinc, on Flickr (please note the actual mask is much darker)
7) On the Group - Sky layer change that to Multiply, Darken can also work but Multiply seems to work better for me.
On the Mask layer, do any clean up. White houses on the horizon will be showing sky, so that will need to be fixed, etc...
9) Adjust to taste.

Sky Added_MG_9736 by cabbiinc, on Flickr
If you really want to make it realistic grab the Pick tool, Mode set to Perspective, and widen the top of the Sky layer (leaving the Mask and Group - Sky alone).
Adjust sharpness, contrast, etc... to match the two images.

I chose this image to try on as there's that fence thing on the horizon. That would be impossible to try to mask by hand.
The full sized image can be seen at http://farm8.staticflickr.com/7165/6798 ... abea_o.jpg