Masking in Photoshop
In the last blog I discussed blending images to get a better final result, specifically replacing a perfectly clear blue sky with one that had more character (clouds).
There are many ways to create selections in Photoshop, including the Color Selection tool, the Magic Wand tool, the Pen tool, the Lasso Tool, as well as the use of plugins, such as TopazLabs ReMask. Depending on the image you are working on, any one of these tools can be helpful. In this blog, I am going to layout the steps for masking using the Color Selection tool in Photoshop.
Select your base image. In this case, I selected an image from the Montgomery County Fair, of the swing. As you can see, there is NO sky here and I am getting aberration (vignetting) from my lens. To get this image ready, I processed the image using an HDR technique, to pop the beautiful undercarriage of the ride and the people in the seats.
After collapsing my layers, I duplicated my background layer, then I created my mask selection by through Select, Color Range, and used the dropper to pick up the areas of the sky. In this case, I picked the sky near the top and the bottom of the image, so that I got both “blues”. use the dropper to choose the “colors” to pick up. Then hit OK. This will give you the marching ants.
You can see in the image below this “marching ants,” indicated my selection. It doesn’t matter in this case that the corners are not in my selection. I will be able to fix that later.
Then click the Mask tool button shown below. This will create a mask. You must remember to duplicate the background image before selecting your color range.
Result, you can see our duplicate layer with a mask next to it in the layer panel on the right hand side.
Next select the appropriate sky image. Remember when making this decision, angle of the sky is important. For incorporation into this particular base, I would not select a sky taken on the horizon, it would simply be too far away. Also, consider the color (hue and saturation) of the sky you are going to use. Although this can be manipulated in processing, you can save yourself time by selection something similar. Lastly, you need to consider “light”… say from the time of day perspective. I could not use a night sky here, because there is too much light on the faces of the people on the ride and direction of light should be considered as well. I chose the sky image below.
I did do a bit of processing on this image. Deepened the blues in the sky and lightened the clouds, through Brightness and Contrast adjustment in Photoshop.
Duplicate the mask, so that it is also on the sky layer. To do this, hold down the option (or alt) click, click and hold the mask you want to duplicate and drag it up to the sky layer, and unclick. This will copy the mask you created and place it on to the sky image, allowing the background layer (base layer) to show through. As you can see in the image below the vignetting in the corners is back and the masking is quite complete on the top left, but never fear… we will fix that next!
You can feather your mask at this point, but for this image, feathering would have created a small blue line around the ride, which would not have allowed the sky to look natural. Therefore, I left the feather control at zero.
To clean up the mask, you need to show the mask on the screen, instead of the image. To do this hold down the option (or alt) key and click the mask (on the sky layer). This will bring the mask on to your Photoshop workspace.
Depending on how clean your Select, Color Range was, you will have more or less black or grey in the sky. In my case, I could have clicked the corners during the range selection and that would have made this cleaner. In either case, we can fix it, but selecting the Brush tool and making sure white is selected as our “color” to paint. Then start painting the unwanted blacks and grays white.
Now that we have cleaned up all the excess black (on the area that is supposed to be white) and cleaned up the excess white (on the area that is supposed to be black), we are ready to reveal our final image!
Again, holding the option (or alt) key, click on the layer mask (on the sky later). This will return to image to your workspace and presto chango … we have an image with some character in the background now!
Remember, this technique can be used for all sorts of images. Maybe head shots taken against a boring white background and you want to add color or textures. Adding a moon to an otherwise featureless night sky. The possibilities are limitless.