Key points
- A negative prompt is a separate field for writing down what you don't want to appear in the picture. It sits alongside the field for what you do want.
- What's written there isn't a ban — it's a push in the opposite direction. It doesn't guarantee something stays out.
- It works best on recurring failures: blur, cropped framing, mangled text.
- More isn't better. Add two or three at a time and expand based on the results.
- Some tools don't have this field. In that case, writing what you do want more specifically works better.
The analogy
Open a sticker book to decide what goes where, and it's not just about picking which stickers to use. Sometimes you set a few aside in a separate tray, deciding "not these today." Stickers in that tray don't get reached for, so they naturally thin out of the finished page. A negative prompt is that separate tray. Write down what you don't want to appear, and the hand reaches for it less.
Setting a sticker in the tray doesn't make it vanish, though. Since it's only about reaching less often, one can still slip in by accident. And setting too many aside leaves too few stickers to use, so the page ends up sparse. Deciding what to leave out takes as much care as deciding what to include.
In detail
The include field and the exclude field move independently
An image generator starts from a hazy screen and gradually settles it into shape. At every step, it works out "the direction that moves closer to what was written" and takes a step that way. Write something in the exclude field and one more calculation gets added. The direction toward what was requested and the direction toward what was excluded get worked out separately, and the result pulls toward the first and pushes away from the second.
So the exclude field isn't a tool for erasing something already drawn — there's nothing on the screen yet to erase. It's closer to a running instruction, saying "not that way," the entire time the picture is being made.
The pull and the push get stronger together through a single knob called guidance scale. Set it too high and the picture overshoots what was wanted. If colors blow out or shapes fall apart, try lowering the guidance scale first, or trimming what's written in the exclude field.
What's worth writing there
The exclude field works best on recurring failures. Generate several pictures from the same sentence and notice the focus keeps missing, the subject keeps getting cropped out of frame, or lettering on a sign keeps coming out mangled — write down exactly that symptom. Blurriness, cropped framing, mangled text, a smudged background — these are the words that belong here.
Some things don't work as well. The model can't push away from a direction it doesn't know, so an unfamiliar brand name or a brand-new slang term written here tends not to get pushed away, and the picture may just drift a little in an odd direction. Counting is a weak spot too, since counting things is already a soft point for image generators.
It's also a problem when what's excluded overlaps with what was requested. Ask for a snowy street while excluding white, and the snow itself may turn gray or thin out. Check first that the two fields don't share the same subject.
More isn't better
The first time someone tries the exclude field, everything that comes to mind gets listed. But the more that gets pushed away, the narrower the space the picture has left to land in. A striking layout, a bold color, unusual lighting — these tend to sit far from an average picture. Block off enough of those directions one by one and what's left is a plain, flat scene.
Add two or three at a time, check whether the intended failure went down, then add more one at a time. That's the only way to tell which words actually did the work. Dump ten in at once and there's no telling what caused the change.
On tools without an exclude field
Plenty of tools have only a single request field. Writing "without such-and-such" inside that sentence doesn't always work well, depending on the tool. In generators that are poor at reading negation, a sentence gets read as one whole direction, so what's named as absent can show up on screen anyway.
In that case, write what should fill that spot instead of naming what to leave out. Wanting a street with no people means writing an empty dawn street rather than asking to remove people; wanting a background that isn't messy means writing a plain background. Filling the space with what's wanted, rather than leaving a gap, tends to work far better.
More precisely
Whatever gets written in the exclude field turns into a bundle of numbers the same way the main request does. At every step, the generator produces two predictions: one that treats the request as a condition, and one that treats the excluded text as a condition. The gap that points from the second toward the first gets amplified by a fixed multiplier to decide the actual direction of the step. Leave the exclude field empty and an unconditioned prediction fills that spot instead. Guidance scale is exactly that amplifying multiplier.
The analogy breaks down in one place. A sticker is a single physical piece, so setting one aside leaves the rest untouched. The exclude field isn't a single piece — it's a direction, so pushing away one word pulls its neighbors along with it. Exclude darkness and an entire night scene can disappear. In the tray analogy, one sticker only occasionally slips back in, but the exclude field only lowers a probability, so generating several pictures from the same request can still leave it showing up in a few of them.
Try it yourself
Common misconceptions
It's easy to think writing something in the exclude field guarantees it never shows up, but actually it only lowers the odds, so it can still turn up in a few pictures out of several.
It's easy to think more entries makes the picture cleaner, but actually the space the picture can land in narrows, leaving flat, similar-looking results.
It's easy to think writing "without such-and-such" in the main sentence has the same effect, but actually, depending on the tool, that word can get pulled onto the screen instead.
One-line summary
A negative prompt is a field that pushes the picture away from whatever's written there, and it works best when it names a recurring failure in two or three words at a time.
Spotted an error or have a better analogy? Suggest an edit · Last updated 2026-10-17