Add "colored inner hair" to the negative prompt for the black hair.
For finer results, I recommend pairing it with ADetailer.
This is 園城寺怜 / Onjouji Toki from Anime "咲-Saki- 阿知賀編 episode of side-A"
动画《天才麻将少女 阿知贺篇 episode of side-A》的角色“园城寺怜"
Well, because the Danbooru training data has some images with black hair and some with purple hair, the model ends up generating colored inner hair — purple inner hair, which is a bit embarrassing. To fix this and make the hair one color, add "colored inner hair" to the negative prompt.
Danbooru的图有的是紫发，有的是黑发，模型混起来了，变成紫色内挑染了……如果想要纯黑发，就把"colored inner hair" 加到负面提示词里去。
Trained on Illustrious-XL v0.1
========PROMPTS========
Base Character:
shimizudani ryuuka,black hair,Default:
senriyama school uniform,red neckerchief,white thighhighs,