HDR Post-Processing Tutorial

This tutorial will cover how to edit those HDR photos that you have taken as explained in the first tutorial "The Basics of HDR"

Every has their own different ways to process their HDR photos. For me, I edit my photos using Photomatix and then subsequently by Photoshop. I like my HDR effect to have less saturation and more details.

Today we are going to work on this sunset photo. This is a regular un-edited sunset photo taken using regular settings. Sunset? Not too visible.

 Our final product. A HDR sunset photo.

It takes me roughly about an hour to get to this. If this is your first time working with HDR, be prepared to spend many hours working on a HDR photo. Also don't be discouraged if your HDR photo doesn't turn out good. It takes practice to perfect the skill. I too, is practicing daily. Let's begin!

Editing in Photomatix

First, bring up your Photomatix application and click on the "Load Bracketed Photos". As mentioned in my basic HDR photography tutorial, you should have taken at least 3 shots of varying exposure. Browse for the photos and click ok.

 A preprocessing option dialog box will appear. The defaults is fine, but we want to reduce the noise on the underexposed image as it's a sunset and the lack of light will generate more noise in the image. we don't select reduce chromatic aberrations because photomatix doesn't do a good job removing it, and we'll address the issue later in Photoshop using a fast and easy method.

Because by the selective deghosting is selected by default, we will reach a screen like the one below. Normally, when shooting scenes like this example, there isn't any moving objects fast enough to register a change in the 3 photos you have taken, so we'll skip this.

selective deghosting does not repair motion blur due to long exposure. It just fix differences between the 3 photos

A HDR photo is generated! Sure it looks like sh*t now, but that's ok.

Now, SAVE this photo by clicking on the save button before doing anything to this photo. This is an important step because we would have to use this later.

Click on the "Tone Mapping / Fusion" button and we'll arrive at this page with a number of sliders. If the default is not the first preset "Enchancer - Default", then manually click on that preset as shown by the red arrow. Actually the default enhancer is already pretty good, but the default does not fit every scene and preference, so we're going to do a little adjustment here. 

We won't use most of the sliders, but the sliders that we are using are shown in the red box. If you want to know what each slider does and my recommended settings, please see my previous post: The Basics of HDR. Tweak it however you want, but do keep in mind that this is just a base to work on, so it is 100% alright for your photo to have low contrast, and low saturation. Once you're happy with it, click on the process button and let it chew through your photo.

Do not over saturate the photo by using too much color saturation. It only destroys the picture.

Once you're done, save your photo, and we'll call it tonemapped photo. Next, open the first ugly HDR photo that I asked you to save earlier on.

This window will appear. Click on the "Tone Mapping" button.

 Now, we're going to create a black and white high contrast image of your original photo. The idea of creating a photo like this is to use as an overlay over the original photo. This increases the edge contrast for the photo without affecting the tone of the colors in the photo. To do this, retain all the previous settings and reduce the color saturation to 0, change the Lighting Adjustments to medium or surreal, bring the white point and black point all the way to 5%. Click process when we're done.

Save the black and white photo under another name, and we'll call this the shadow. And that's all we need to do in photomatix! The rest is now in Photoshop.

Editing in Photoshop

Open your tonemapped and shadow photos in Photoshop. Make sure the both files are sitting in the same document. If it's not, duplicate the shadow onto the tonemapped photo.

With the shadow layer selected, Change the blending mode to soft light. Soft light is the softest blend of the overlay group as it retains the most colors. If you like a harsher shadow, choose overlay, or even harsher shadows, hard light. In this example, I find soft light a little too harsh for my liking, so I turned down the opacity of the shadow photo to 75%. Hold down CTRL + ALT + SHIFT + E, and it will create a layer copy of the visible layers.

Next step, we are going to fix those chromatic aberrations (CA). Generally, when there is chromatic aberration, there will be two colors appearing on either side of an object. It's usually purple and green, or a similar shade of color. Click on Image > Adjustments > Hue/Saturation, or CTRL + U, to bring up the Hue/Saturation dialog box. Click on the tiny hand icon as show with the red arrow, and a Eyedropper tool will appear. Using that tool, click on a purple CA area that best represents the average shade of purple in the picture (as shown in red circle).

If there are any purple CA that is not selected by dropper, you can use the dropper+ tool (middle tool of small red box), to select those purple. Vice versa, the dropper- tool removes colors you do not want to be included from the selection.

Using the Saturation and Lightness sliders, adjust until the purple CA cannot be seen (or significantly less visible). We've adjusted the saturation and lightness sliders to -75 for both. Our goal is to desaturate and blend the purple CA into the photo.

Zooming out, we can check if by desaturating the purple CA, we have affect the purple in the photo which you do not want to affect. In this case, the floor tiles and the roof (marked in red circles) are of a similar shade of purple. That is the downside of using this tool; it targets CA very well, but it affects similar colors in the whole photo. But go ahead and click OK, and we can fix that later.

Click on the "Add layer mask" as pointed out by the red arrow to create a layer mask. A layer mask shows or hides a certain part of the photo as required. A white layer mask shows, and a black layer mask hides. Now press CTRL + I, to inverse the color of the layer mask to black. Now the picture is completely hidden like nothing has been done yet. Making sure we have selected the black layer mask, and our brush foreground color is white (as shown in red boxes), select the brush tool (or keyboard shortcut "b") and paint over the parts that we want to have the purple CA removed. And there we have it. We removed the purple CA without affecting other parts of the photo.

Create a layer copy of the visible layers (or 2 just for backup), and repeat the steps for removing CA for the green CA. For the green CA, it will be slightly trickier because there are a lot of greenery around the photo and we don't want to desaturate the grass and trees. In this case, once we have selected the green that we want to remove, we can pull the two tiny triangles closer together in the pair of rainbow colored stripes in the Hue/Saturation dialog box. Zoom out and ensure the grass and tress are not affected by the desaturation. We might have to keep trying to find a shade of green that only affects the green CA. But once we're done, click OK.

Now, I'm going to introduce a Photoshop plug-in that is extremely useful to any photographers, amateurs or professionals. That has to be Nik Software. The first piece of Nik Software that I'll be using is the Nik Software Dfine 2.0. This is a tool to remove excessive noise from the photo so it doesn't look too grainy. Do not over use this tool because denoising an image will cause it to lose sharpness. Another thing to remember is to always perform denoising before sharpening (if you need to). In this case, I used the manual method because I want a little more control over the denoising, but automatic works great as well.

While we're at it, I find that the tree by the left of the picture seems a little distracting, so using content-aware, we removed the tree. Simply use the lasso tool to encompass the tree, right click over the lasso area, and click "Fill" option. Ensure Content-Aware is selected and press OK. This step can be anytime, but it is always recommended to remove any large objects from the picture early in post processing as it can be harder for content-aware to generate the image when details are pulled from the picture in the later steps.

Next, we'll be using another Nik Software plug-in, Color Efex Pro 4.0. This is by far the most useful tool I ever used and I always use this for my HDR photos, and frequently for other photos. Firstly, we want to pull more details from picture, so we use the "Detail Extraction" filter. The defaults are usually fine for me, so we go on by clicking the "Add Filter" button. We can always come back later and tweak the settings if you're not happy with it.

Next we add the filter "Tonal Contrast". This filter adds contrast to the picture without ruining the colors. The effects are a little too strong for my liking, so we turn the opacity down to 60%. To pull a little more detail from the image, I set the contrast type to "Fine". The rest of the sliders are on default.

What is a sunset without warmth? Our picture doesn't too much of a sunset feel because it's lacking warmth, so using the "Brilliance / Warmth" filter, we add 75% warmth and 10% saturation to the photo.

The last filter we will use is "Darken / Lighten Center". As the name suggest, this filter lightens the center and darkens the borders. It's similar to vignetting but we have the option to lighten the center to draw the viewers' attention. In this case, we will set the center luminosity to 0% (no change in brightness), and reduce the border luminosity to -25% to give it a little vignetting effect. Press OK when we're done and let the plug-in chew through the photo while we take a minute break.

 

 Because extracting details from the photo amplify those small details and those undesirable noise, we will have to do another denoise. For this case, we're cool with the noise level in the ground area, but not the sky, so we select the sky using the Quick Selection Tool (or keyboard shortcut W). Then we use Dfine 2.0 again to remove excessive noise.

Next, we use another Nik Software plug-in, Sharpener Pro 3.0, to give it a little sharpening before publishing the image. Do not over sharpen the image or it will show visible noise and degrade the overall aesthetics of the image.

One last thing that I have done is to bring the photo over to the latest Photoshop CS6 and used the Adaptive Wide Angle filter to correct the distortion present in this image. As you can see, the lamp post is now standing straight, instead of slanting before applying the filter.


There we have it, the final HDR photo!

If like this tutorial, please share it on facebook, twitter, or whatever. And if you're inspired, please create a HDR photo and comment on this post, with your photo. Enjoy and don't forget to have fun!