Making a PhotoShop Graduated ND filter
1. Open the image you want to adjust.
2. Create a new layer - on the task bar, press Layer/New/Layer (or use the shortcut - Shift/Control N for Windows users; Shift/Command N for Mac). Rename the layer Grad ND so youíll know what it does. Also, set the opacity for overlay and leave it at 100 percent for now. You will now have an empty layer on top of your background layer.
3. Making sure you are working on the empty layer, pull up your gradient tool (under the paint bucket in the toolbar). Look on the task bar and make sure you have a gradient that goes from black to clear; if not, open the gradient picker by pressing on the down arrow next to the gradient colors you see. You should have a linear gradient (first option on the types of gradients shown on the task bar); the mode should be normal, and the opacity 100 percent.
4. Place your cursor at the top of the image (assuming you want to darken the sky; you could also darken the foreground by starting at the bottom of the image), left click on your mouse to set your starting point, and while holding down the left button, pull down to a point below your horizon and release. You might have to experiment here to get the look you want - just undo the gradient and redo it setting your ending point where you think it would look better. If some areas are darker than you would like, donít worry about it - you can use a layer mask to lighten them, as explained in step 5.
With Grad ND applied at 100 percent opacity
If the Grad ND makes the sky darker than you would like, just adjust the layer opacity in the layer window until you get the effect you want.
5. Unlike Grad ND filters on your camera, when you use a PhotoShop Grad ND, you have complete control over what areas get darkened so if you donít have a perfect horizontal horizon running all the way across your image, you can bring back the lightness in areas you didnít want to get darker. To do this, you create a layer mask. In the layers window, press the layer mask button (it looks a bit like a camera). Then, select the layer mask by placing your cursor on the layer mask in the layer window (it should be the white box in the Grad ND layer next to the box which shows your gradient) and pressing the left mouse button. Go over to the tool bar and make sure that the foreground color is black and the background color is white. If not, change them (left click on the one you want to change and enter all zeros for black or all ď255" for white in the RGB boxes). Go up to the paintbrush tool and select a soft round brush. If you want to get the dark areas all the way back to what they were before you applied the Grad ND filter, set the brush opacity at 100 percent; if you donít want to adjust them all the way, lower your opacity to a level you like.
Grad ND at 60 percent opacity
Now, just paint with black over the part of the image you want to lighten. Since you are painting on the mask, it doesnít paint your image black; instead it brings back any of the background layer that was affected by the Grad ND layer. For more intricate parts of the image, zoom in, make your brush smaller (use the bracket keys on your keyboard to change brush size - ď[ď makes it smaller; ď]Ē makes it larger), and paint over those areas.
Hungerford Bridge, London, England
If you make a mistake and paint back an area you didnít want to paint back, donít worry. Just swap the foreground/background colors so that white is the foreground, and paint back your layer effect.