Here's a more detailed explanation:
* Dark Hair Pigment: Dark brown hair contains a lot of brown and potentially black pigment.
* Red Dye Limitations: Red dye often struggles to show up well on dark hair, especially without pre-lightening.
* Resultant Colour:
* The red will likely deposit on the surface of the hair, giving it a reddish sheen or tint, especially in sunlight.
* It might appear as a warmer, more auburn or mahogany shade of brown.
* If the red dye is a very strong and highly pigmented shade, you might get a more noticeable red tone, but it still won't be a bright, fire-engine red.
To achieve a true, vibrant red on dark brown hair, you would need to lighten the hair first (using bleach or a high-lift color) to remove some of the existing dark pigment. This creates a lighter base for the red dye to adhere to and show up properly.
Keep in mind that results can also vary depending on the specific red dye used, the health of your hair, and how porous it is. It's always a good idea to do a strand test first to see how the dye will take to your hair.