In the UK, the weather is neither the most predictable nor the sunniest and let’s be fair, it is the butt of many jokes. However the law of averages says that sometimes, just sometimes, it must work in our favour. Suddenly you have a gorgeous clear day and out you go, shooting away without a care in the world. When you get home and review your shots, you realise that the cloudless sky looks too bland. A sky without clouds just isn’t as exciting to look at.
It is ironic though, that the lovely blue sky is very helpful in adding a totally new one! We could go straight for the Refine Edge tool but as is the way in Photoshop, there’s more than one way to approach this technique. Here’s a nice quick and easy method that works well with blue sky replacement.
Step 1 – We have our original image which was taken on a lovely day but the sky is a little boring, so we can use the blue sky to help us select this area to fill with a new, more interesting sky.
Step 2 – You need to choose something that won’t look out of place or just plain odd when you drop it into your original image. Try to pick a sky with similar lighting conditions and shot from a similar perspective.
Step 3 – Now copy your sky image and paste it into your original scene. You should now have two layers, the base layer and a new layer above it covering the area we want to replace, which we shall name ‘sky’. For the moment, make this layer invisible.
Step 4 – Make sure the ‘Background’ layer is active and go to the toolbar and select the Magic Wand Tool (W). Set the Tolerance to about 30 and check both the Anti-alias and Contiguous boxes.
Step 5 – Click the cursor in the sky area and a selection will be made. Press the Shift key and a small plus symbol appears by the cursor and you can continue to click and add more areas of the sky to the selection.
Step 6 – Because the neighbouring cliff edge is tonally different, the Magic Wand will only pick up areas of the blue sky. As you get down to the sea, it will have more trouble telling the difference between sky and sea. That’s not a problem.
Step 7 – Go to the toolbar and select the Rectangular Marquee Tool (M). Press the Alt key and a small minus symbol will appear next to the cursor. Drag a rectangular selection that runs along the horizon and also encompasses any stray selection areas in the sea.
Step 8 – When you let the mouse button go, the marquee you just drew will clip the selection and you will have a nice sharp line on the horizon. You now have your basic selection of the sky area, outlined by the ‘marching ants’.
Step 9 – With the selection still active, click on the Refine Edge button at the top of the screen. This will open the Refine Edge dialog box.
Step 10 – Make sure the Smart Radius box is checked and make the Radius about 2px. Make the Shift Edge value about +60% and click OK.
Step 11 – A much more accurate selection will be made, more closely following the edge of the cliff edge to give a cleaner line.
Step 12 – Click back on the ‘sky’ layer and make it visible again. You will be able to see your selection outlined against the new sky. Keep the ‘sky’ layer active and click the Add Layer Mask button at the bottom of the layers palette.
Step 13 – The new ‘sky’ layer will have a mask added to it in the shape of the selection you created. Anything white in the mask allows the new sky to be seen, any part of the mask in black allows the Background layer to show through instead.
Step 14 – Your new sky is in place, making the overall picture more interesting. You need never have to worry about a featureless blue sky again.