Stop-motion photography

Mount the camera on a tripod at a right angle to the subject's path. Frame the scene with plenty of space at the sides, above, and in front. To ensure that every frame is identically composed, do not adjust the zoom or pan the camera. Focus on the subject and set the camera's focus mode to manual. Set a small aperture to keep the subject sharp if it moves a little toward or away from the camera. I also like to set the camera's exposure manually and wait for a moment when the lighting is constant.

From now on, all you need to do is release the shutter. If your camera can shoot rapid bursts of pictures, just ask the subject to move and fire away. Alternatively, shoot each frame individually, and then move the subject. Shoot as many frames as you need to capture the movement and to give you plenty of choices. In my series, inspired by a Muybridge shot of a woman stepping over a chair, I thought that eight frames worked well, and I asked each of the subjects to repeat the movement three times.

Open the best images in Photoshop, but don't adjust or crop them yet. Activate a picture in the sequence, hold down the Shift key, and drag the thumbnail from the Layers palette and drop it into the first picture's window. The Shift key makes sure the image is centered. Repeat the process for each shot, so they end up stacked in sequence in one document. If your computer is short on memory, you may have to keep open just the first picture and then open each subsequent file, drag and drop its picture, and close it again.

We need to crop the combined image, but to allow for the movement, it's useful to turn off the visibility of all the image layers except the top (last frame) and the last (first frame), and set the top layer's opacity to 50%. Use the Crop tool to select the area, double-click inside the selection box to apply the crop, and restore the last layer's opacity to 100%.

We need to resize the images so that they're smaller. This is a simple calculation. Multiply the paper size by the printing resolution (usually 300 ppi) to get the total paper size in pixels, and then divide by the number of framesin this case eight. Round down the result and record itI noted down 700 pixels. Then choose Image > Resize and enter the final picture size. I used 675 pixels because I allowed for a margin round each picture.

To make the Photoshop document large enough for the final layout, unlock the background layer by double-clicking on it and naming it Layer 0. Now use Image > Canvas Size, click the top-left Anchor square, enter the total paper width in pixels that you calculated in step 5 (see the box), and click OK.

Photoshop's Offset filter makes positioning layers easy and consistent. Activate Layer 1 in the Layers palette and choose Filter > Other > Offset, enter the space per pixel, and click OK. In this case I used 700 pixel measurement that I noted down at step 5. Then activate Layer 2 and press Ctrl/Cmd + F twice. For Layer 3, press Ctrl/Cmd + F three times and continue until all images are correctly positioned.

Here I have created two more rows of images for two more boys, but you could choose any number you like. To merge everything into one file, first flatten each sequence using Layers > Flatten Image. Then create a new file of appropriate width and heightin this case 5700 x 3900 pixels-and drag each flattened sequence into it as you did with the individual frames. Adjust their positions using the method from step 7. Finally, I added the sepia tone with a Hue/ Saturation adjustment layer and carefully masked it in the same way as I used for ambrotypes and tintypes (see page 42).