When crafting prompts for AI image generation tools like Stable Diffusion, you may notice creators using various punctuation marks like parentheses “()”, brackets “[]”, and braces “{}”. These punctuation marks serve important functions in controlling how the AI interprets and prioritizes parts of your textual prompt.
Parentheses in particular are very commonly used to indicate emphasis or priority on certain prompt components. By wrapping prompt terms or phrases in parentheses, you are essentially telling Stable Diffusion: “Hey, pay special attention to this part!”
Why Use Parentheses for Emphasis in Stable Diffusion Prompts?
Parentheses are an easy way to weight or boost parts of your prompt without having to mess with more complex numerical weighting. Simply wrapping a term in parentheses gives it more priority and influence on the final output image.
For example, if you write:
a photo of a (fluffy) catThe AI will emphasize “fluffy” more when generating the cat image. Versus if you just wrote:
a photo of a catThe cat may or may not end up fluffy without that extra parentheses boost. Parentheses give you more direct control to get what you want without having to try multiple prompt variations or tweak numerical weights.
How Many Parentheses Should You Use?
As a general rule, the more parentheses you wrap around a term, the more priority/emphasis it will have. For example:
(fluffy) cat - More fluffy
((fluffy)) cat - Very fluffy
(((fluffy))) cat - Extremely fluffy!However, be careful about going overboard with tons of parentheses as it can sometimes throw off the balance of the prompt. 3-4 levels of parentheses is usually a good amount for most use cases.
Advanced Uses and Examples
Beyond just boosting adjectives like “fluffy”, parentheses can be used for all kinds of creative applications:
Emphasize Multiple Terms
You can wrap multiple prompt components in parentheses to give them all priority:
((fluffy, orange, happy)) catAdjust Style/Mood of Images
Add parentheses around emotional descriptors to influence the style and mood of generated images:
A photo of a ((happy)) family at the beachBoost Specific Details
Bring out intricate details by emphasizing descriptors for things like clothing, accessories, etc.:
A fashion model with ((intricate, golden)) earringsMake Comparisons
Use parentheses to compare characteristics. For example, generate one image with the term boosted, and another without:
((Tall)) man wearing glasses
Man wearing glassesEmphasize Entire Phrases
You can wrap whole phrases or concepts in parentheses too for emphasis:
An astronaut floating in space with ((a galaxy visible in the background))The key is to think about what exactly you want the AI to focus on most from your prompt, and wrap that part in parentheses!
Prompt Structure Tips
Here are some additional prompt structuring tips to use parentheses effectively:
Place Early In Prompt
Put the parenthesized term(s) near the beginning so they have influence throughout image generation.
Use Selectively
Don’t overdo it! Use parentheses selectively just for your 1 or 2 most important prompt aspects.
Pair With Other Controls
Combine parentheses with other controls like numerical weights for precise tuning. But start simple with just parentheses first.
Common Questions
Here are answers to some frequently asked questions about Stable Diffusion’s parentheses:
Do Parentheses Work the Same in Other AI Models?
Parentheses may have slightly different effects in other AI image generators like DALL-E 2, Midjourney, etc. But the basic concept of using them for emphasis is similar.
Is There a Difference Between Parentheses “()” vs Brackets “[]”?
Parentheses typically indicate a stronger weight/priority than brackets. Brackets are more for weak emphasis. Some models may interpret them differently, so experiment!
How to Do Negative Prompts With Parentheses?
Simply put a minus sign before the parentheses. For example:
Cat -(black, orange)) Will avoid generating black or orange cats.
Hopefully this gives you a great starting point for leveraging parentheses effectively in your Stable Diffusion prompts! Let your creativity run wild.
Useful Prompt Engineering Resources
Here are some useful sites with more Stable Diffusion prompt ideas and examples:
Stable Diffusion Prompt Guides