Yes, you can paint on a black shirt! In fact, black shirts are great canvases for painting because the dark color provides a nice contrast for your design. However, there are a few things to keep in mind when painting on black fabric.
First, make sure to pre-wash your shirt before painting it. This will help set the fabric and prevent the paint from bleeding or fading after you've applied it.
Next, choose an acrylic paint that is specifically made for use on fabric. These paints have a built-in medium that helps them adhere to fabric better than regular acrylics.
When you're ready to start painting, sketch out your design on paper first. This will help you plan where each color should go and avoid any mistakes. Once you're happy with your sketch, begin painting! Start with light colors and build up to darker shades so that any mistakes are less noticeable.
Finally, let your paint dry completely before wearing or laundering your shirt. Acrylic paint needs 24 hours to cure fully, so be patient! Once it's dry, your design will be set and ready to show off.