For: Lightroom 3+

• Create your watermark image in Photoshop or another graphic editor
  • Make sure it’s big enough that it won’t need to be scaled up
  • Make sure the background is transparent
  • Simplify any color schemes
  • Make sure your text has a contrasting border
  • Save your watermark image as a 24-bit PNG (PNG-24) with transparency
• Create a Watermark to apply to your images on export in Lightroom
  • Open the Watermark Editor (Edit -> Edit Watermarks…)
  • In the top right corner where it says Watermark Style, pick “Graphic”
  • In the Open File dialog that pops up, navigate to where you saved your watermark image from your image editor
  • Adjust the opacity, proportion, inset, and anchor point under Watermark Effects to position the watermark where you want it
  • Save your watermark by clicking the save button in the lower right corner of the Watermark Editor window
    • If there is no save button, or you’re updating an existing watermark, use the Save Current Settings as New Preset or Update Preset… options from the drop-down menu in the top left corner of the Watermark Editor.
• Close the Watermark Editor window, and begin using your watermark when you export images