Hello, I have preview 10.1 on my Mac. I have a music score. How can I high passage in yellow but still can see through the notes? ( like a yellow magic marker on paper)? Thanks.
Preview allows you to draw shapes and fill them with a color at any level of opacity. The Opacity is set in the color picker window which pops up if you select the "Show Colors" button a the bottom of the little Color drop down menu.
If you "click" on the marker-pen button, it gets highlighted. Click on the arrow-down to select an option (in fact, if you click first here, & select, the marker button goes "on"; shorter). Click on text and drag cursor to highlight. You can also select text and highlight it from up-menu/Tools/Notation/Highlight (selected effect will be applied).
"Preview" remembers last effect you selected, even after closing the app.
If your music sheet is not formatted, then you should fiddle with free-draw tools, from the button close to search bar. From there you can chose color & line styles; the trick to make a see-through marker is to reach "color palette" window, where you can assign opacity (default 100%).