Anyone Know How To Make Tiny Stripes In Photoshop?

[GreenShirt 0]

I need to make a grating (equal width black and white stripes). So far I have gotten them down to 12 black stripes per centimetre, but I’d like to have it down to 16 or so.By trial and error I’ve been doing it this way: fill the screen with a gradient tool (black), and then Filter>Distort>Wave, settings set to: type-square, generators-999, wavelength-12/12, amplitude-999/999, Scale-100/100, Repeat edge pixels. I’m using high contrast (as black as possible), but eventually I will vary the contrast.-Is there a way to make the stripes thinner? -What do the settings mean? I’m using it to check animals' vision. Thanks!