Magic+Wand+tool

Magic Wand Tool
4th tool - click and hold down to get magic wand tool Can be used to delete a day sky and make a night sky. Select tolerance of 1 in options bar - this only lets you pick one pixel of the colour Increase tolerance to 32 lets you select a variety of colours eg within a sky. Make sur anti - alias key is ticked for smooth borders - then select delete key and colour disappears. OR edit - undo Magic wand tool - select same area then click shift key to add more blue areas Zoom into remove smaller areas decrease tolerance when doing smaller areas Click on hand tool

The magic wand tool is essentially a selection tool
The moment you select pixels in photoshop, any other commands performed after the selection, will only be performed on what has been selected. eg in a picture with sky, select the sky using the shift key with with the magic wand Apply a filter only to that selection eg layer new adjustment layer - brightness and contrast - pick a colour OK Then adjustments on the left drag arrow across to the colour you want the sky to be.

OR

Magic Wand with night sky
Click on background in the layers section - right click background and click layer from background OK Click on add a new layer - second symbol from the right down the bottom Move it down under the layer 0 Make layet 0 invisible by clicking on the eye next to it Go to Google - find picture of night sky zoom in right click copy image - edit paste in photoshop on the new layer. Click on tool under top arrow, Select the image by dragging a rectangle bigger than it. Click Edit - free transform - drag to make it big If there is a bit you do not want then click edit - free transform then select the tool under the top arrow and drag a rectangle to the size you want. Make the picture cover the whole work area Click enter Unhide layer zero select blue sky in layer zero click delete - the dark sky shines through Make sure layer 0 is at the top then layer 1 Use magic wand to pick any areas to delete and fix up. Layer 1 shines through layer 0