Images · guidance updated 4 Oct 2026
FLUX (Black Forest Labs, e.g. in Krea) prompt guide
FLUX 3 (unified image/video, announced 23 Jul 2026) is rolling out; FLUX.2 [pro/max/flex/klein] remains the main production model in third-party tools. Both use prose prompts, no negative prompts, quoted text and hex colours. Krea defaults to 'Auto' model selection.
How to prompt FLUX (Black Forest Labs, e.g. in Krea)
- Write natural-language prose, not tag lists.
- Open with one sentence that sets image type and medium, then subject and action, setting, light, and framing.
- Put what matters most first; FLUX weights early words more heavily.
- Aim for roughly 30–80 words; go longer only for multiple subjects, precise layouts or text.
- Describe visible details instead of relying on names, and drop filler like 'highly detailed' or 'ultrarealistic'.
- For photos, name camera, lens, aperture and film stock ('Shot on Kodak Portra 400, 85mm, f/2.8').
- Describe light by source, quality, direction and colour, and say what it does to the scene.
- Quote exact text with intended capitalisation, give its placement and describe weight, case and colour.
- Attach hex codes to specific named objects ('the awning in #E07B39').
- Phrase exclusions positively ('an empty, deserted street'); there is no negative prompt.
- With reference images, refer to them by position ('the jacket from the first image').
The shape of a good prompt
[Image type and medium, one sentence]. [Subject + visible details] [action]. [Setting and surroundings]. [Light: source, quality, direction, colour]. [Framing: shot size, angle, lens, depth of field]. [Style/era, palette with hex codes]. Text "[Exact Words]" [placement], [weight, case, colour].
Avoid
- Negative phrasing or a 'negative prompt' list
- Comma-separated keyword stacks and SD-style weights like (word:1.3)
- Quality filler ('8k, masterpiece, hyperdetailed')
- Vague colour words where an exact hex value matters
- Midjourney-style --parameters
Example
Request a cozy coffee shop poster for autumn
Vertical vintage screen-printed poster with flat inks and visible paper grain. A steaming ceramic mug of spiced latte sits on a wooden window ledge in the foreground. Behind it, a quiet, empty corner street on a rainy autumn evening, maple leaves on wet cobblestones and tall café windows glowing warm amber. Soft light from the windows rims the mug's steam. Palette of burnt orange #D2691E, mustard #E1AD01 and deep teal #0F5257. The headline "AUTUMN BREWS" spans the top in bold cream serif capitals; "Pumpkin spice • Maple latte • Chai" runs along the bottom in small sans-serif.
