About the d: tag
d: is a face tag that NovelAI Diffusion can use. On Danbooru it has 8,661 posts, and its best-rated still image scores 2,400. The samples above put the tag at the front of a fixed base prompt with seed 1234, so the differences between tags come from the tag alone.
How each model draws d:
Follows composition and expression instructions closely, so the effect shows in a tidy form.
Reacts to the tag more strongly, so its effect is easier to see.
WAI illustrious SDXL v17, a local model. Shows how the same tag reads outside NovelAI.
Writing d: in a prompt
Put the subject first, then this tag, then quality tags.
1girl, solo, d:, best quality, masterpiecewlop, 1girl, d:The negative prompt and the full settings are on the terms page.
How these samples were made
Every image uses 832×1216, seed 1234, 23 steps and the k_euler_ancestral sampler. The base prompt and negative prompt stay the same for every tag, and only the tag under test changes. Images flagged by the NSFW check are regenerated with a new seed or hidden.
From the Danbooru wiki
An unhappy, displeased, or distressed face with a flat-bottomed open mouth. The opposite of :D.
Actually "D:", in lower case due to technical limitations.
Examples
See also
FAQ
Does NovelAI recognize d:?
Compare the samples on this page. Every tag on this site shares the same seed and base prompt, so any change you see comes from d:.
How do I write d: in a prompt?
Write "d:" near the front of the prompt and separate it from other tags with commas.
Should I use V5 or V4.5?
V4.5 shows the tag's effect more strongly. V5 gives steadier images with fewer artifacts.