An actress wears a blue dress. How could you use spotlights to make the dress appear black?

I think you could use black spots.
Is this right?

Thank you.

You could use a red spotlight. Red light would not refect much off a blue dress, so it would look black. Unfortunately her face would be red.

Spotlights can indeed be used to create optical illusions on stage, but using black spots may not be the most effective way to make a blue dress appear black. Black spots could create a patchy effect on the dress, which might not achieve the desired result.

To make the blue dress appear black using spotlights, you can try the following technique:

1. Remove or reduce any direct light falling on the actress: Start by ensuring that there is minimal or no direct light illuminating the actress or the blue dress. This can be achieved by positioning the spotlights strategically to avoid light spillage onto the dress.

2. Use backlights: Place backlights behind the actress, closer to the background. Backlights can be adjusted to illuminate the background more intensely and create a silhouette effect on the actress. This will make the dress appear darker in contrast to the background.

3. Adjust spotlights in front: Position spotlights in front of the actress at angles that minimize direct lighting on the dress. Experiment with different angles and intensities to achieve the desired effect of making the blue dress appear darker or even black.

4. Implement lighting filters: Consider adding color filters to the spotlights to further darken the blue dress. For instance, placing a dark blue or purple gel filter in front of the spotlights can help in shading the dress and making it appear black.

It's important to note that achieving the desired effect depends on various factors, including the intensity and positioning of the spotlights, the color and material of the dress, and the overall stage setup. Therefore, it's always recommended to experiment, adjust, and fine-tune the lighting to achieve the best results.