Ok Davie, try this. Example photo below.
1. Open your image.
2. Select the type tool.
3. Set the text color to 50% gray. (Use HSB values 0-0-50 or RGB values 128-128-128 - both give the same result).
4. Choose a fairly heavy typeface. I used Arial Black.
5. Type in the text you want to use for a watermark. If you want the copyright symbol hold down the ALT key and
on the numeric keypad type 0169. When you release the ALT key, you have the copyright symbol
6. Click the commit button to add your text.
7. Switch to the move tool to resize and position your text. Double click to commit the changes.
8. In the
layer styles palette choose Bevels from the pull down menu.
9. Click on Simple Inner effect.
10. Double click on the circled f symbol of the type layer in the layer palette to bring up the style settings dialogue.
11. Adjust the bevel size and lighting angle until it's to your liking. I used 30 degrees for the light and 7px for the Bevel Size.
12. Click OK.
13. In the layers palette, change the blend mode for the type layer from Normal to Hard Light.
That's it. If you want the watermark to be more visible use an HSB value of 0-0-60 for the text (step 3) or for less visible try 0-0-40. Experiment
Malky