The phrase "to filter the light" means to block or adjust the intensity, color, or direction of light in order to create a specific effect or to control the amount of light that passes through. Full definition
Keep the seeds in a dark place with a small amount of filtered light until sprouts appear. (chilipeppermadness.com)
The handy blackout lining filters light so you can keep your space perfectly dark, while the cool stripe print offers a relaxed and versatile look. (pbteen.com)
While you'll want a well - lit room as your photography studio attempt to filter the light through a soft curtain which will soften it and provide for better photos. (babygaga.com)