Seán Duggan: Gradient Adjustments  (Part 1)
Apr 2014 09

Gradient adjustments are some of the most powerful, yet also most simple modifications that can be applied to your images. A gradient adjustment describes a change, be it a color or tonal adjustment that is applied so that there is a gradual fading from the adjusted to unadjusted area. In composites, gradient masks can be used to seamlessly blend different image elements together. In part 1 of this article, we’ll take a look at gradient adjustments that can be applied in the camera, via a graduated neutral density filter. In subsequent parts, I’ll cover post-capture gradient adjustment techniques in both Lightroom and Photoshop.

In-Camera Gradient Adjustments

Although we have a tremendous amount of control in terms of how we work with our images in the post-processing phase of the photographic workflow, sometimes, when the conditions are right you can apply a gradient adjustment at the time the image is captured. The graduated neutral density (ND) filter has long been an essential piece of gear for many landscape photographers, and for good reason. These filters consist of a darker, neutral area (meaning it will not introduce any color cast) that gradually fades to clear. Below are Galen Rowell 2-stop graduated neutral density filters from Singh Ray, in both soft and hard transitions.

Graduated ND filters are ideal for scenes where the sky area is brighter than the lower part where the landscape is, allowing you to cut back the amount of light from the top portion of the image.

Graduated ND filters are commonly available in both circular and rectangular formats, as well as different sizes. Rectangular filters typically require a slotted bracket or filter holder that screws into the filter ring on your lens. The example shown below is a Singh Ray filter in a Cokin “P” series filter holder.

Rectangular filters provide the most flexibility since you can adjust the position of the gradient in relation to the scene you’re composing. This is not possible with the circular filters, where the split between the ND part and the clear area is always right in the middle. In terms of composition, placing the horizon in the exact middle of the frame can sometimes work, but a non-centered placement is more effective for many landscape images.

Diagonal Corrections

Correcting for brightness differences in scenes where the horizon is straight and level is probably the most common way to use graduated ND filters, but if your filter allows you to choose how the gradient blend is applied to the image, it can also be useful in other scenarios. Consider the image below of the bicyclist in Death Valley: the area to be darkened by the graduated ND filter is along a diagonal line. By rotating the filter holder, I was able to position the darkening exactly where I needed it.

Reversed ND Corrections

Most uses of graduated ND filters are typically for the skies of landscape scenes, but they can work equally well if you need to darken the lower portion of a composition. In the image of the Death Valley salt flats below, the bright, reflective surface of the dry lakebed was very different from the darker mountains and sky at the top of the image. The graduated ND filter holder was rotated and positioned so it darkened the bright areas in the bottom two thirds of the scene, yielding a more balanced exposure for the entire scene.

Beyond the Camera

As useful as graduated ND filters are, there are times when it may not be practical to use them, or when the types of corrections you need go beyond basic darkening. Fortunately, for those cases, programs such as Lightroom and Photoshop provide a number of ways to apply enhancements and modifications. In the next installment of this article we’ll delve into software-based gradient corrections in Adobe Lightroom and Photoshop.

Seán Duggan is a fine art photographer and the co-author of Photoshop Masking & Compositing, Real World Digital Photography, and The Creative Digital Darkroom. He leads workshops on digital photography, Photoshop and Lightroom.