Thank You Again CHG_CANON (Fellow Contributors) I discover & learn something new every time I visit this link. Now that makes me . . . . . Smile, JimmyT Sends Bravo Zulu
Why not just take a manual writing instrument (pen & ink) and actually write your signature on the print - there are all sorts of suitable pens/markers with various color ink options available - simple, affordable and personal!
Do you use Lightroom Classic? It does watermarks in any color and it has a slider for transparency. You can also chose font, size and position. #1 opacity 100% #2 opacity 25%
Photologo does a nice job and you can size the watermark so that it's unobtrusive. If you use software that can work with layers you can also vary the transparency of the watermark.