Compositing Images

[Alan9940]

Hello All,

I thought this would be something simple to do, but I seem to be having great difficulty in that PL isn't doing what I expect!

OK, here's the layout... I've got a base layer (landscape image with bald blue sky) that is 3000 x 4000 px and I want to replace the bald sky with some nice clouds. I used the auto transparency tool to remove the sky of my base image, opened a separate landscape with nice clouds and used the rectangle lasso to select a portion that is approx 3000 x 1300 px, copied that selection to the clipboard, closed the cloud image, then pasted the cloud selection into my original document as a layer. Then, I used the Layer Tool to slightly transform the clouds and re-position as needed.

Therefore, I now have two layers: the base layer is my original image with transparency where the old sky used to be, and layer 2 holds my "cloud piece" with quite a bit of transparency below it (I'm assuming PL sizes the pasted layer to same size as the original document?). Now comes the strange part... When I grab the cloud layer and move it below the original image layer weird things happen: I loose about half my original image off the bottom and about 1/2 a page of white canvas is added to the top. Huh? Can't I simply move my cloud layer behind my original image layer and have a normal looking image with clouds? This would be so easy to do in just about any other image editor!

I would really appreciate any guidance provided. Thank you.

Best regards,
AlanH

[greenmorpher]

Allan, why not try a little experiment.

Make sure the original document is a PLD format document because you are going to want to copy transparency.

Set up a new document that is 4000 x 3000.

Copy the cloud layer and paste to the new document so it becomes the base layer, then copy the current base layer to the new document and paste in as a layer so it is the top layer.

Cheers, geoff

[chrischa]

Hi Alan,

the picture size is defined by the background layer. If you move your sky-layer to the background, the size of your picture changes. You can switch to document mode, that doesn't care about the size of the first (background) layer, or you can move a copy of your background image above the cloud-layer.

I personally would use a layer mask to put some clouds into a bald blue sky: Open original image, copy background layer, paste sky with clouds and move this layer in between the first two. Select sky with automask on top layer, create a layer mask from this and edit the layer mask with a soft brush for a smooth transition. You also could add a layer mask on the cloud-layer, too, paint on it with a soft brush and adjust the blue tone with a hue/saturation-layer. Advantage: Alls steps are non-destructive and can be corrected.

Hope, my english is good enough to help you.

Christoph

[bkh]

Now comes the strange part... When I grab the cloud layer and move it below the original image layer weird things happen: I loose about half my original image off the bottom and about 1/2 a page of white canvas is added to the top. Huh? Can't I simply move my cloud layer behind my original image layer and have a normal looking image with clouds? This would be so easy to do in just about any other image editor!

Alternatively to Christian's suggestions, you could use "Layout -> Image -> Bring to document size" on the clouds layer before you move it backwards. Another option would be to make a copy (or a virtual copy which hardly uses additional storage) of your background layer and move it in front of the clouds layer.

Cheers

Burkhard.

[Hoogo]

I'm using the current beta, it seems to behave a bit different than I expected. I can't verify the behavior you described, so I make a guess: There are "picture mode" and "document mode".

Picture mode:
That's what I know from my old PSP and from PS.
It's the background layer that determines the properties of the whole picture: The size in pixels, colorspace and bit depth in which all layers are calculated. Also in PS the background layer behaves a bit different than all other normal layers, you can't move it in the layer list and some functions are not available, iirc. In PL you have the restriction that you cannot distort the background layer with the handles.

When you move another layer to the bottom of the layer list, normally that layer will determine all the properties afterwards.

Document mode:
There's an imagined background layer. It's drawn like a sheet of paper, and the properties are stored in their own tab an the attributes-dialog. This looks more like some layout programs, where you can position layers on a document.

When you move a distorted layer to the bottom of the layer stack, you create something that is not possible in the usual picture mode. Then PL will switch to document mode. At least this is the behavior I remember and that I expect from the official version.

Tip:
Go to the attribute dialog an switch to "document mode" right after opening the picture, or at least before you move the distorted layer to the bottom. It does not behave that different at all, and I can't remember any disadvantages.

Edit: Wow, so many people still active at this time? Shortly after midnight in Germany.

[Alan9940]

@greenmorpher - thanks for the great suggestion.

@Christoph - your English is fine! Generally, I too would use layer masks to maintain a non-destructive workflow. In this case, I didn't think I'd ever be concerned with the bald sky, again, so was comfortable with simply removing it. I will, however, play more with this image and the masking technique because there are some small wispy areas of desert vegetation that still reveal some "blueness" around edges. As you suggested, some combination of soft brush masking and careful hue/saturation adjustment should take care of this issue nicely.

@Burkhard - yep, the "Bring to document size" on the cloud layer before moving did the trick, too. But, my absolute favorite is your tip to make a virtual duplicate of the base layer and move the clouds layer in between. I saved a copy when done and checked the file size against the original; no change! What a tremendously powerful technique in PL!!

@Hoogo - yeah, honestly I've never understood Picture mode and Document mode and where/why I'd choose one over the other. I assume Document mode would be very useful doing layouts and when using vector graphics or drawing, but since I'm a photographer my head starts spinning when anyone starts talking vectors! Therefore, I guess that since I'm always opening pixel-based image files that I'm always in Picture mode and never pay attention to it.

Also, following up on Hoogo's comment regarding how late it was in Germany...THANK YOU or danke! (man I hope that's German for thank you!)

Best regards,
AlanH