How to Auto-Align Layers in Photoshop CS6
One of the coolest features in Photoshop CS6 is the Auto-Align Layers command. How many times have you taken photos at a reunion, wedding, or other family event where not one of the shots is perfect? In one shot, Aunt Marlene has her eyes closed. In another, Momma Sue is looking to the side for Junior who should be in the photo.
The Auto-Align Layers feature enables you to take these multiple images and composite them into that perfect shot by aligning your image and then letting you mask out the parts of the image that you don’t want.
You can also use the Auto-Align Layers feature to stitch together images, such as panoramic shots or scans of oversized images — that is, any series of images that have even a slight overlap.
Follow these steps to Auto-Align your layers:
Create a new document with the same dimensions as your source images.
Open all your source images. With the Move tool, drag and drop each image into the new document.
Each image should be on a separate layer.
If you desire, you can choose a layer to use as a reference. Lock the reference layer.
If you don’t set a reference layer, Photoshop analyzes the layers and then selects the layer in the center of the final composite as the reference.
In the Layers panel, select all the layers you want to align and choose Edit→Auto-Align Layers.
Choose one of the projection methods:
Auto: Photoshop analyzes the layers, decides which method would create the best composite, and then applies the alignment.
Perspective: Photoshop designates one of the layers as the reference layer. The remaining layers are transformed so that content is aligned.
Collage: This option enables you to move, rotate, and scale your layers to get your desired layout.
Cylindrical: This is a good option for panoramic shots. It places the reference layer in the center and then places remaining layers on an unfolded cylinder to minimize distortion.
Spherical: This option also places the reference layer in the center and places the remaining layers on a sphere to correct distortion. This option comes in handy when you want to align shots taken with a wide-angle lens.
Reposition: A good option when you need to stitch together oversized scanned images.
Check options to correct for lens problems, such as Vignette Removal and Geometric Distortion.
Vignetting is an exposure problem caused when light at the edges of the images is reduced and the edges become darkened. Geometric Distortion refers to such problems as barrel (bulging out) and pincushion (pinching in) distortions.
Photoshop finds and aligns the common areas of the layers. If you’re stitching together images, you’re done. If the composite has visible seams or inconsistencies, you can apply the Auto-Blend Layers command.
If you’re creating the perfect shot, add a layer mask to your top layer, set your foreground color to black, and use the Brush tool (with the appropriate tip size) to paint over the portions you want to hide or delete. In a mask, black hides pixels, so the layer underneath shows through. Repeat this process of layer masking your content until you have the shot you want.