Upload & Sell: On
My customers could care less whether my signature has been digitally placed on a print or if the print is actually signed by myself. Since I am not involved in the handling of my prints that I sell, my copyright signature is placed on the digital image that the lab prints.
Several people have asked how to do this, so here is my method:
The size of signature that I use is what I feel appropriate for a digital image 5200 pixels x 3500 pixels at 72 pixels/inch. You can make yours larger if you want. Once you have created your signature image at this size, you can always downsize it and save several smaller versions for smaller images.
In Photoshop: File > New > 5200 x 3500 @ 72 ppi, background colour black, and name the file "copyright" or whatever.
Now choose an appropriate size brush and use a drawing tablet to draw your signature in white. Save the file.
Now when you want to apply your signature to an image, simply select your white signature, copy and paste it into your new photo, move to where you want it, fade to an appropriate opacity, then flatten your image. If you will be pasting your signature onto a white portion of an image, you can change your signature to any colour you want before copying and pasting it.
If you don't have a drawing tablet, you can either try using your mouse, or use the Type Tool for your name and copyright symbol.