By following the steps in this GIMP project you will see how to use layer blending modes and a variety of tools to create the effect of a ghost appearing in the forest.
Some of the concepts used in this project:
- Adding an alpha channel
- Desaturating an image
- Cropping to a fixed aspect ratio
- Using the Fuzzy select tool
- Opening an image as a new layer
- Using Layer masks
- Using Layer modes
- Selecting using transparency (Alpha to selection)
- Stroking a selection
I used this image of a lady from stock.xchng as the basis for the ghost. The first step is to eliminate all the white background around the lady and replace it with transparency. Begin by using the Crop Tool to eliminate most of the background area.
Add transparency to the image, Layer > Transparency > Add Alpha Channel. Pick the Fuzzy Select Tool and click and drag forward in the background. This will select most of the white background without selecting anything within the lady herself. (You might want to use Quick Mask mode to be certain that no part of the lady is selected and to clean up your selection if necessary.)
Feather the selection about 5 pixels, Select > Feather... . Clear the selection, Edit > Clear.
Deselect, Select > None. Zoom in on the lady and use the Eraser Tool to manually clean up any remains of the white background around the edges of the lady.
Convert the lady to a black-and-white image, Colors > Desaturate... with Luminosity selected in the dialog. Select Brightness-Contrast... in the Colors menu. Slide the Brightness down to about -50 and the Saturation up to about 30 to give the image a darker appearance.
Now, fade out the lower part of her body. Add a white layer mask, Layer > Mask > Add Layer Mask... . With the Blend Tool, drag a FG-to-BG gradient (default colors) vertically from the bottom of the image to about the level of her waist.
Finally, scale the image to a height of about 850 pixels, Image > Scale Image... . Save and close the image of the lady.
Moving on to the forest image. As the source for the forest, I used this image, also from stock.xchng. The first step is to crop out a portion of the image with the Crop Tool, in the Tool Options, select Fixed Aspect Ratio of 5:8.
Resize the resulting image to a height of 1200 pixels, Image > Scale Image... .
Open the previously saved image of the ghost lady as a new layer in the forest image, File > Open as Layers... . Make sure the image and not the mask is active in the ghost lady layer. Use the Move Tool to position the lady where you like. Set the Layer Mode to Overlay in the Layers pallet. Reduce the Opacity to about 60%.
Duplicate the ghost lady layer, Layer > Duplicate Layer. Set the Layer Mode to Grain Merge and reduce the Opacity to about 25%. Apply a Gaussian blur with a Radius of 10 to the ghost lady copy layer, Filters > Blur > Gaussian Blur....
Add a soft glow around the ghost. Again, open the saved image of the ghost lady as a new layer. Rename this layer as glow. Delete the layer mask, Layer > Mask > Delete Layer Mask. Temporarily hide all the other layers by clicking the “eye” icon for each.
Now, to paint a white border around the lady. Select the image of the lady, Layer > Transparency > Alpha to Selection. Swap the default colors. Now stroke the selection, Edit > Stroke Selection..., Line width: 10 px. Clear the selection. Deselect.
Apply a Gaussian blur of 20 px. Unhide the other layers and use the Move Tool to position the glow layer around the ghost.
Swap the default colors back to black FG and white BG. Add a mask to this layer and fade it exactly as you did to the ghost lady layer earlier.
Experiment with various settings as you try out this lesson. Changing just a few things can dramatically affect the results you get. I hope you have fun playing around with this project.