My failure to pull off the messed-around-with photo of the keyboard the other day was really bugging me, so today I decided to give it another go. Last time I took a single image and used the clone tool in Aperture to make the changes. This time I took multiple images and used layers in Photoshop. I'm much happier with the results!
Here's how I did it:
I took five photos: one for the background, and one each for the transplanted letters (L, O, V and E). So that every letter would be the right size and shape, I had to get each letter in the same position within the frame as it would appear in the final composition. I did this using the AF points as guides. I also propped the keyboard up so that it was horizontal, because the letters are on different rows of the keyboard, so if I hadn't done this, the letters in each row would be at a different angle to the camera when pulled into the middle of the frame.
When I'd finished shooting, I imported all the photos into Photoshop. I used the clone tool to erase the letters on the four keys on the background image where the new letters would go. I then used the magic wand tool to select the new letters on the other four images, jumped each of them onto a new layer, and then used the move tool to drag these new layers onto the background image. I found I had to ramp up the tolerance setting on the magic wand, otherwise it cut off the slight blur around the outside of the letters and they didn't look right.
Once I'd got all the letters in position (using a horizontal guide line pulled down from the ruler bar to help me) I then played around with blend modes. In 'normal' blend mode the transplanted letters were lighter than the surrounding letters, and didn't look right at all. I found that 'overlay' gave the best results.
Finally, I flattened the image, and then did all the usual processing. There was a bit of chromatic aberration around the edge of the transplanted letters, but converting the image into black and white fixed this.