Photographers use graduated filters placed in front of the camera lens to selectively change the exposure and sometimes the colour of part of a picture, usually to darken the sky to bring out details in the clouds and balance the exposure with the landscape in the foreground. They come in many different shapes, sizes and colours to fit all types of camera system. As with most photographic techniques, it’s possible to duplicate the effect of graduated filters using Adobe Photoshop, and as usual there are several ways to accomplish this. For this example we’ll use an image of the Royal William Yard in Plymouth taken on a sunny, but slightly misty day with a pale blue sky.
Graduated Filter in Adobe Camera Raw
With any photo taken using Raw mode, we can use the Graduated Filter tool in Adobe Camera Raw (ACR). ACR is the Raw processing application supplied with each version of Photoshop, and allows you to add the effect during processing. This is by far the best way to do it, since it preserves the maximum amount of detail in the photograph.
Step 1 – When you open the image in Adobe Camera Raw, you’ll see a row of tool icons across the top of the main image window. The Graduated Filter icon is to the right..
Step 2 – When you click on the Graduated Filter icon, you’ll see the control panel on the right of the screen change. The filter can apply many different effects, but the one we want to use is a reduction in exposure. A setting of -1.75 should produce a suitable effect for this picture.
Step 3 – To apply the filter, drag a line down from the top of the screen to the horizon line. You’ll see a horizontal and vertical dotted line like an inverted T. You’ll also notice that you can change the angle of the line by moving the cursor left and right. To constrain the line to the vertical, hold down the Shift key while dragging.
Step 4 – The red dotted line marks the lower, least saturated edge of the gradient effect, but there is also a green line at the top of the frame. This marks the top or most saturated edge of the effect, with a smooth gradient between the two lines. If you drag this green line down, more of the image will be at maximum effect and the gradient will be shorter.
Graduated Filter in Photoshop
If you have a jpeg image and prefer to use Photoshop to achieve the graduated filter effect, here is a useful and simple way to do it.
Step 1 – If your photo wasn’t taken in Raw mode, you can apply a graduated filter using the Gradient Tool. To set up the graduated filter, first select the Gradient Tool, then set the foreground colour to blue by clicking on the foreground square and then using the colour picker.
Step 2 – Next, in the tool options bar, click on the gradient editor and select Foreground to Transparent, click on the button for Linear Gradient, set the Blending mode to Multiply, and the Opacity to 75 percent. Make sure the boxes for Dither and Transparency are checked.
Step 3 – To apply the gradient to the picture, start at the top of the frame, click and drag down to the horizon line. If you hold down the shift key it will constrain the line to the vertical. The result should look something like the image shown.