🥠Prompt
Overview
Developing a process to build good prompts is the first step every Stable Diffusion user tackles.
Anatomy of a good prompt
A good prompt needs to be detailed and specific. A good process is to look through a list of keyword categories and decide whether you want to use any of them. For example, subject, medium, style, artist, website, resolution, additional details, color and lighting.
Subject
The subject is what you want to see in the image.
Medium
Medium is the material used to make artwork.
Style
The style refers to the artistic style of the image.
Artist
Artist names are strong modifiers. They allow you to dial in the exact style using a particular artist as a reference. It is also common to use multiple artist names to blend their styles.
Website
Using them in a prompt is a sure way to steer the image toward these styles.
Resolution
Resolution represents how sharp and detailed the image is.
Additional details
Additional details are sweeteners added to modify an image.
Color
You can control the overall color of the image by adding color keywords.
Lighting
Lighting keywords can have a huge effect on how the image looks.
Negative prompt
Using negative prompts is another great way to steer the image, but instead of putting in what you want, you put in what you don’t want. They don’t need to be objects. They can also be styles and unwanted attributes. (e.g. ugly, deformed).
The negative prompt helped the images to pop out more, making them less flat.
Using negative prompts is a must for v2 models.
Here are some universal nagative prompt:
ugly, tiling, poorly drawn hands, poorly drawn feet, poorly drawn face, out of frame, extra limbs, disfigured, deformed, body out of frame, bad anatomy, watermark, signature, cut off, low contrast, underexposed, overexposed, bad art, beginner, amateur, distorted face, blurry, draft, grainy
Prompt syntaxes apply on AUTOMATIC 111 GUI
Keyword weight
You can adjust the weight of a keyword by the syntax (keyword: factor). factor is a value such that less than 1 means less important and larger than 1 means more important.
() and [] syntax
An equivalent way to adjust keyword strength is to use () and [].
(keyword)increases the strength of the keyword by a factor of 1.1 and is the same as(keyword:1.1).[keyword]decrease the strength by a factor of 0.9 and is the same as(keyword:0.9).
We can use multiple of them, just like in Algebra… The effect is multiplicative.
(keyword): 1.1 ((keyword)): 1.21 (((keyword))): 1.33
[keyword]: 0.9 [[keyword]]: 0.81 [[[keyword]]]: 0.73
Keyword blending
The proper term is prompt scheduling.
The syntax is [keyword1 : keyword2: factor]
factorcontrols at which step keyword1 is switched to keyword2. It is a number between 0 and 1.
How long can a prompt be?
In the basic Stable Diffusion v1 model, that limit is 75 tokens.
Prompt limit in AUTOMATIC1111
AUTOMATIC1111 has no token limits. If a prompt contains more than 75 tokens, the limit of the CLIP tokenizer, it will start a new chunk of another 75 tokens, so the new “limit” becomes 150. The process can continue forever or until your computer runs out of memory.
Each chunk of 75 tokens is processed independently, and the resulting representations are concatenated before feeding into Stable Diffusion’s U-Net.
Credit
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