It's a mixture of red, white, blue and magenta tissue paper and white copy paper.
Here's what it looks like mashed up in my mom's old blender.
This is a sheet laid out to dry. This batch has more of the red and violet colored paper in it.
The batch this sheet came from was made the next day when I added used white copy paper to the leftover violet water, so it's got the barest tint of color to it.