Exploring the software equivalent to graduated ND (neutral density) filters

- Shooting a scene with a lot of dynamic range in it can be tricky because you have to choose whether you're going to expose for either the brightest part of the scene, or the darkest part of the scene. Traditionally, photographers handled this sometimes by using something called a graduated neutral density filter. This was a neutral density filter that screwed on into their lens and had a graduated degree of filtration on it, so that you could darken the top half of the frame and have a smooth ramp into the bottom of the frame. For shooting an image like this, a typical landscape image where the sky is very bright and the horizon is a little bit darker, that was one way to equalize your exposure and pull the scene to within the dynamic range of your camera.

This week, on The Practicing Photographer, we're going to look at some software alternatives to doing that. I don't actually work with physical, graduated ND filters. They're hard, they're hard to work with, and having the right level of gradation and knowing that you've got it in the right place, there's just no need for that anymore. The latitude that we have with editing a high-bit image from a modern digital camera gives us all of the software graduated ND capability that we need, and we gain some advantages over a real-world filter. I'm gonna show you two different ways of doing this.

One in Lightroom and one in Photoshop. I mix and match, sometimes I do this in Lightroom, sometimes I do this in Photoshop, depending on what I need, and I think you'll see the differences pretty easily. Here I am in the Develop module. Obviously, the problem is, the sky is too bright. I'm gonna grab the graduated filter tool, here, and, actually I just turned it off. I'm gonna reset my settings. I'm gonna start here, and drag down to, maybe here. The middle line is the midpoint, the bottom line is where the filter will be totally out.

Now, I'm just gonna drag my exposure slider to the left to darken that bit. You can see that I'm getting a darkening that's much stronger at the top than it is at the bottom. I can go back later, if I want, and adjust exactly how the ramping off is working. Couple of things about this that are bugging me. The clouds shouldn't be that dark, so I'm gonna lighten the shadows up a little bit, hope that that pulls some out. If not, I'm gonna have to just go in here and do that. Or, I can go back in later and separately lighten the cloud.

This is nice, the problem now is, my foreground is actually too dark. I need more contrast on the foreground. I'm just gonna make another graduated filter. This is the cool thing about doing this in software. I can't stack a bunch of graduated ND filters on the end of my lens, I'd end up with just black, and not be able to see anything. I'm gonna hit the New button here, and that gives me a new filter that I can drag out. I'm gonna brighten this and add some contrast. Brighten it some more.

Now, I'm seeing the ramp off a little too quickly, so I'll stretch this out more. There are some areas that are getting brightening from both layers, so I might need to move that around. You'll notice, my cursor turns into this thing. That allows me to tilt the filter so that if my horizon was crooked, or if I wanted to skew brightening from one part of an image into another, along a tilt, I could. If I need to go back and edit the other ramp, I can do that here. Clicking on either of these pins brings up the controls for that ramp.

The problem, here, is this board in the middle, which is crossing over both, I want to tone it separately. I wish it hadn't gotten the darkening from the first ramp, and I'm not sure that I like that it got the darkening from the second ramp. With that in mind, I'm going to delete both of these. I can click on one and hit the delete key, and it's effects vanish. Instead, I'm gonna go do this in Photoshop. I'm going to go to my external editor. Lightroom, of course, processes the RAW image, writes out a TIFF file, opens that up in Photoshop, and here I am.

Now, I'm gonna do my exposure change the way that I normally would with an exposure adjustment layer. It's going to affect the entire image though, which is not what I want. That's darker, but it's darkened the entire image. I have, over here of course, a layer mask, which allows me to constrain the effects of this edit. I'm gonna reset these to black and white and grab my Gradient tool. Now I'm gonna click and hold down the Shift key to constrain my motion to straight lines, and drag down to here, and I get this.

If you look at my mask, you see white are areas that will get the full effect, black get none at all, and there's this gray ramp in between that is smoothly transitioning from one to the other. As I turn this layer on and off, you can see, sure enough, the sky is darkening, the foreground is not. But I want some more contrast in there. Actually, I think I'm gonna jettison that layer and start over. I'm gonna add a Levels adjustment layer and get my change this way. I'm gonna darken this up. That's making for a more contrast-y sky, and it's totally destroying my foreground.

But that's okay because when I drop my adjustment layer in, I get this. That's looking more dramatic. Now, the problem is, it's still hitting this board, which I didn't want. But that's okay because here in Photoshop I've got complete control of my mask. I'm gonna grab some black paint and a brush, and just paint over this, and I'm now excluding this area from that effect. If you look at my mask here, you see this little bit of black poking up here. That's an area that's protected. Now I can make another Levels adjustment layer, and paint a mask in again going this way.

This time, I'm going to brighten the foreground. Maybe even increase the contrast a little bit. My ramp is happening in the wrong place, I don't like being that so dark. What's cool about the Gradient tool, is if I just drag again, it will overwrite the gradient that was there before, so that pushes my transition back a little bit. But again, I don't want the board being impacted by this edit, so I'm just gonna grab some black paint and paint over this, and now the board is not getting any of this adjustment. That said, it does need an adjustment of some kind.

But that's okay, I can now grab it independently and put its tones where I want them. I'm just gonna paint this in sloppy for now. Trust me, it is possible to do a better job. I'm also gonna make a little bit of adjustment there. Finally, I'll add one more adjustment, with the goal of increasing contrast on the board. I'm gonna drag that over there, I'm gonna go ahead and push the whites up, fill this mask with black, and now I can paint that adjustment in. I've got two graduated filters on here manipulating the sky and the foreground, and another adjustment on here that's manipulating the board.

This is something that I cannot do with a real-world graduated filter. It's also something that I can't do in Lightroom. Having both of these tools at your disposal is pretty critical if you do a lot of work in high dynamic range situations, like landscapes. Or, even interiors where you've got window light and whatnot. Any time you're gonna need to compress that dynamic range of the real world down into what the camera can do, this ability to ramp off exposure changes becomes critical.