With Photoshop CS3 or newer, you can load images into a document as layers easily with the Load Layers script. Choose File > Scripts > Load Files into Stack. Browse for the three images then click OK. Enable the “Attempt to Automatically Align Source Images” option. With this option enabled, Photoshop will automatically align the layers to compensate for slight movements. This works almost all the time but in case it doesn’t, you can disable it. Because you’ve already aligned your layers, skip the next step (Step 2 – Aligning the layers).
Using Photoshop CS2 or older
Open all three images into Photoshop. Tile the images so that you can see all three. While holding the Shift key on your keyboard, drag the layer of one document to another. Repeat this with the third image. One of the images should have three layers. Depending on the version of your Photoshop, you may have to reposition the layers so that they look aligned. You can close the other two images.
Step 2 – Aligning the layers
When shooting photos for HDR, many times the photos aren’t perfectly align. Even slight misalignment can cause ghostings/artifacts. Before we proceed, we need to ensure that the layers are properly aligned. If you’ve imported your photos using Photoshop CS3 or newer in the previous step, skip to step 3.
Photoshop CS3 or newer
Photoshop CS3 introduced a new feature called Auto Align Layers. With this command, Photoshop can analyze your layers and automatically align them. Start by selecting all three layers. You can select multiple layers by holding down the Ctrl key on your keyboard.
Choose Edit > Auto-Align Layers. Select reposition as the projection method then click OK.
Photoshop CS2 or older
Unfortunately, Photoshop CS2 or older do not have the auto align layers feature. You’ll have to manually align the layers. However, we’ll show you a neat trick to make this fast and easy. Here’s how to align layers manually: Hide the top layer then set the blending mode of the second layer to difference.
After you change the blending mode to difference, you’ll notice that your image will look inverted and most likely embossed. If there is no embossing, it means that your image is perfectly aligned. If there is embossing, you’ll need to align thelayer. To align the layer, select the Move tool (V) then press the arrow keys on your keyboard to nudge the layer until the embossing effect disappears. Below is an example of the before and after results of nudging.
Change the blending mode of the current layer back to normal. Enable visibility for the top layer then change the blending mode to difference.
Like earlier, select the Move tool (V) then use the arrow keys on your keyboard to nudge the layers so that the embossing effect disappears. Change the blending mode back to normal when you’re done. Don’t forget to crop the image! If you imported the photos from Lightroom, leave the image uncropped and crop it in Lightroom instead.
Step 3 – Applying the HDR tone mapping effect
Before we begin, move the layer with the middle exposure to the bottom. The two layers with the underexposed and overexposed image should be on the top.
In the Layers palette, right click on the layer with the darker exposure then choose Blending Options.
While holding down the Alt key on your keyboard, drag on the all the way towards the right until it is hidden under the . Click OK. What this just did was make the darker parts of the layer transparent. The darker it is, the more transparent it is. Now you have the highlight details taken from the layer with the underexposed image.