a number line on the stage
Yes, for musicals we run numbers across the downstage edge, with 0 at center and going R and L, labeling every 2 feet in each direction (in ballet, I was told, the stage is marked every 4 feet with 1/4 and 1/2 stage featured on either side as well eg sometimes a rope lite along the lip w a specific color light at center, 1/4 and 1/2 stage in each direction - but feel free to correct me please)
Thanks - I was curious about that! It makes sense, and is much more thoroughly divided vs. ballet. At least that doesn't scare me anymore!
Ballet is marked at center (the actual center line of the stage) and quarters (half way from center and the proscenium), with 1/8 marks between center and quarter (called "inside 1/8" SR or SL), and between quarter and the proscenium (called "outside 1/8" SR or SL).
1/8 1/4 1/8 center 1/8 1/4 1/8
Center and quarter are generally black and 1/8 are white - and these are generally spaced 6' apart. [Though if the floor is black, some opt for the all white method, which places "T" at Center and 1/4 and "l" at 1/8's - on the DS & US edges of the dance floor.] Some may spread farther apart, if they decide to scale the marks to the actual proscenium. If you can't do it with 6' spaces between the marks, then you have to scale down so that outside 1/8's fit into the stage.
As far as how the marks are made depends on the company and if you own your own floor. My company has LED markers in contrasting colors (Red & Green) at each mark along the DS edge, and the floor itself is dotted in special stencil spray paint in Black and White as I mentioned above. The dots run the entire stage, from DS to US. For rentals, since we have to tape the marley panels together, we will put spike tape in the proper color on each tape seam, from US to DS, since we cannot permanently mark a rental floor.