There will be occasions when you want to alter only a given part of an image, not make 'global' changes (i.e. to colour/tint etc.) In this situation you should select the area you want to work with using the (Freehand) Selection Tool. The previous task showed how a 'mask' might be made by selecting a particular area. This task aims to look at selections further, including adding to and subtracting from selections to make more complex 'masks'.
For this task we'll be using the yellow car image, which can be found here.
First load the yellow car image. Make sure it fills the workspace and if possible zoom in to the top left quadrant of the image.
Then select the Freehand selection tool from the tool bar (arrowed). It is important then to set the parameters of the tool in the Tool Options bar. The type should be 'Point to Point' and there should be no Feather. The options are indicated by the red box.
Just as you did with the scratched picture retouch, add a new raster layer with the left most icon in the Layer palette (arrowed).
You will see the dialogue box on the right. No changes are necessary, just click OK to make the layer.
Now you can start making the selection. Choose a good place to start, in this case I have started on the top of the bonnet, tracing the outline of the car by clicking then moving. A bit like doing a join the dots puzzle. You will see a translucent blue/red trace line where you selected.
Continue right round the car bodywork. Don't worry about 'running out of picture' when you reach the edge of your zoomed image, it will scroll automatically to reveal more of the image.
Working your way around the whole image, double click when you reach the point where you started, to 'complete' the selection.
Now you will need to 'cut out' certain areas from your main selection, such as the piece behind the roll bar and headlamps etc.
To to do this, you will need to 'remove' or 'subtract' further selections from your main selected area. This is done by selecting the Freehand tool again, but in the tool options setting the mode to 'Remove' (indicated by the red box).
Now when you select inside the roll bar area, your old selection is retained and your new selection 'removed' from the main selection.
Continue with this technique to 'Remove' or 'Add' parts of the image as necessary.
Note that you can hold the CTRL and SHIFT keys down as you select to also 'Remove' from or 'Add' to selections.
When you are happy with your selection, you can achieve various effects, for example 'tinting' the car with another colour, by filling the selection with a colour and then experimenting with opacity/transparency to achieve the effect on the left.
See if you can 'Add' to the selection you have to tint the wheels as well.