Do AI models understand Kelvin numbers?

Treat a Kelvin value as a hint and add the plain color word, as in "warm tungsten, about 3200K". None of the prompting guides from Google, OpenAI or Black Forest Labs that we read explains how their models handle Kelvin values, so check the render.

Can I name a classic setup, such as three-point lighting?

Yes. Google’s prompting guide for Nano Banana uses "three-point softbox setup" as an example. Add what the setup should do to the product, because the same three lights can be placed many ways.

Why does my product look like it is floating?

It has no contact shadow. Say where the shadow falls, for example "a soft contact shadow where the base meets the table". See how to make AI product photos look real.

Lighting words that work in AI image prompts

Checked September 24, 20269 min read

Short answer

Describe light the way a gaffer would: the source (window, softbox, bare flash, the sun), how hard or soft it is, where it sits relative to the camera, and what it does to a named surface, such as a tight shadow under the base or a thin highlight down a bottle’s edge. The kept Nano Banana prompts from our 2026 campaigns all wrote light as something happening to a surface.

How to write one lighting sentence

A lighting sentence needs the source, its hardness, its direction from the camera, what it does to a named surface, and where the shadow goes. Add the color of the light when it matters.

Lighting sentence

[Hard or soft] [source] from [direction relative to the camera], [what it does to a named surface], [where the shadow falls and how sharp its edge is].

This line is from a prompt behind a kept food ad: "Hard direct flash carves ultra-sharp shadows beneath each piece, revealing wet fudgy shine across the top surface in deep chocolate tones (#2A1610)." The light has a type and a hardness, it does something to a surface, and the shadow has a place. "Dramatic lighting" would have left all of that to the model. Google’s own prompting guide for Nano Banana uses the same kind of language in its examples, such as "Golden hour backlighting creating long shadows".

Lighting terms, what they look like, and when to use them

Term	What it looks like	Use it on products for	A line to try
Hard flash (bare or direct flash)	A small, bright source: dark shadows with crisp edges and bright specular highlights. Pointed straight at the subject from the camera, it flattens shape.	Bold snack, candy and drink ads; motion frozen mid-air	"Hard direct flash from just above the camera, a crisp shadow falling down and right of the can"
Soft window light	A large source from one side: soft shadow edges and a gentle fall from light to dark. Cloud or a sheer curtain makes it softer.	Food, home goods, skincare on a table	"Soft window light from camera left, fading to shadow on the right side of the jar"
Softbox	Diffusion fabric over a light, making the source bigger and softer; on glossy surfaces, a clean rectangular highlight	Packshots, bottles, cosmetics	"A large softbox above and left, one clean rectangular highlight along the bottle’s shoulder"
Strip light (strip box)	A long, narrow softbox: soft along its length, harder across its width, with long thin reflections	Bottles, cans, glass, dark products that need an outline	"Two strip lights behind the bottle, one each side, drawing thin white lines down both edges"
Beauty dish	A round dish with a center deflector: crisp but soft-looking light and round catchlights	Beauty and cosmetics shown on a face	"Beauty dish just above the model’s face, round catchlights, soft shadow under the chin"
Rim light (edge light)	Light from the side or behind that outlines the subject; strongest against a dark background	Dark products on dark grounds, hair, glass edges	"A thin rim light from behind camera right tracing the edge of the black tube"
Backlight	The source behind the subject, facing the lens: separates it from the background, lights up see-through materials, or makes a silhouette	Drinks, oils, serums, steam, anything translucent	"Backlight through the amber bottle, the liquid glowing, the label side in soft shadow"
Top light	Light from straight above: shadows fall directly under objects; on faces, shadows under the eyes and chin	Flat lays, food from above, packs on a table	"Soft top light straight overhead, a tight shadow directly beneath the pack"
Gobo or dappled light	A pattern of light and shadow from a cut-out, blind or leaves placed between the light and the subject; closer to the light, softer edges	Summer lifestyle, skincare, drinks; a sense of place without props	"Hard sun through leaves, dappled shadows across the bottle and the stone surface"
Golden hour	The sun within about 6 degrees of the horizon: warm, low light and long shadows	Outdoor lifestyle, apparel, drinks	"Late golden-hour sun from behind camera left, long warm shadows across the sand"
Blue hour	The sun about 4 to 8 degrees below the horizon: a blue sky and cool, even light, with lamps and windows glowing warm	Evening drinks, city scenes, anything with lit windows or signs	"Blue-hour sky, cool ambient light, warm café windows glowing behind"
Overcast	The whole sky as one huge soft source: faint shadows, low contrast, a cool cast	Outdoor apparel where you want soft, even light	"Flat overcast daylight, soft shadows, even light across the fabric"
High key	Mostly bright tones with few dark areas; low contrast between key and fill	Clean ecommerce, skincare, baby products	"High-key white set (#FFFFFF), soft light all around, only a faint shadow under the base"
Low key	Mostly shadow, with strong contrast between the lit parts and the rest	Spirits, fragrance, tech, premium food	"Low key on black, one narrow source from the left lighting only the front edge of the bottle"
Chiaroscuro	Italian for "light-dark": a strong pattern of light and shade that models form, a term from painting	Painterly still life, luxury, food	Google’s own example: "Chiaroscuro lighting with harsh, high contrast"
Split lighting	The key at 90 degrees to one side: half the face lit, half in shadow	Moody fashion and grooming portraits	"Split light from camera left at 90 degrees, the far side of the face in full shadow"
Butterfly lighting	The key above and centered in front of the face: a small butterfly-shaped shadow under the nose	Beauty and makeup close-ups	"Butterfly lighting, key high and centered, small shadow under the nose"
Rembrandt lighting	The key raised and to one side: a small triangle of light on the cheek away from the light	Portraits with character in brand stories	"Rembrandt light from camera left and above, a small triangle of light on the shadowed cheek"
Color gels	Colored filters in front of lights: colored light and colored shadows	Nightlife, youth brands, drinks, bold ads	"A magenta gel on the rim light from behind left, a cyan fill from the right"
Practical lights	Lamps, neon, candles or screens that appear in the frame and light the scene	Evening interiors and lifestyle scenes	"A brass table lamp in frame is the only light, a warm pool on the table"
Bounce	Light reflected off a card, wall or ceiling: larger, softer, and tinted by the surface it bounced off	Lifting the shadow side of a pack	"A white bounce card at camera right lifting the shadow side of the box"
Negative fill	Black card or cloth that absorbs light: deeper shadows and more shape where light was flat	Glass and bottles that need dark edge lines; matte products that look flat	"A black card at camera left adding a dark edge down the bottle"
Raking light	Light skimming across a surface from the side at a low angle, so every raised bump casts a small shadow	Fabric, leather, paper, crusts, cream swatches	"Low raking light from camera left across the knit, each rib casting a small shadow"
Glass on white, glass on black	On white, black cards at the sides draw dark edge lines; on black, lights or white cards behind the glass draw bright edges. Photographers call these bright-field and dark-field.	Glassware, perfume bottles, clear liquids	"The glass against black, two strip lights behind it outlining the rim and stem in white"

Directions are from the camera’s point of view. The lines are starting points; swap in your product and surface.

Direction words

Say where the light is from the camera’s point of view: "camera left" is the left side of the picture as the viewer sees it. "The left" alone is ambiguous, because a person facing the camera has their left on the viewer’s right.

Direction	Where the light is	What it does to a product
Front	Beside or behind the camera, pointing at the product	Even, flat light; labels read clearly; little shape
Three-quarter (45 degrees)	Halfway between front and side	Shows shape: one side bright, one side in soft shadow. The usual key for packshots.
Side (90 degrees)	Level with the product, to one side	Strong texture and drama; half the product dark
Back	Behind the product, facing the camera	Glowing edges and see-through materials; the front goes dark unless filled
Top	Directly above	Shadows straight down; good for flat lays and food
Under	Below the product, pointing up	Unnatural on faces; used through a light table to make glass or liquid glow

Hard and soft light, and why

Hardness depends on how big the light looks from the product. A small or distant source makes crisp shadow edges; a large or close source makes soft ones. The sun is enormous but so far away that its light arrives from one direction, so direct sun is hard light, while cloud turns the whole sky into one soft source. Move a softbox closer and its light gets softer. Say both the source and its hardness, because "window light" is hard when the sun shines straight through the glass.

Light also weakens with distance. Under the inverse square law, a small light moved twice as far away delivers a quarter as much light. A light close to the product lights it far more than the wall behind, so the wall goes dark. Photographers use this to turn a grey wall black without changing the wall, and the effect is worth writing into a prompt: "a small light close to the product, the background falling off to black".

Color of the light

Light	About	What it looks like	A line to try
Candlelight	1,000 to 2,000 K	Deep orange	"Lit only by candles, deep orange light, black shadows"
Household tungsten bulb	2,500 to 3,500 K; tungsten film and studio lamps are balanced to 3,200 K	Warm, yellow-orange	"Warm tungsten lamp light, about 3200K, cool daylight from the window behind"
Electronic flash and daylight	Flash 5,000 to 5,500 K; daylight film is balanced to 5,500 K	Neutral white	"Neutral daylight-balanced flash"
Overcast sky	6,500 to 8,000 K	Cool	"Soft overcast light, slightly cool"
Open shade or heavy overcast	9,000 to 10,000 K	Blue	"Open shade, cool blue light, no direct sun"

Kelvin ranges from Cambridge in Colour’s white balance guide; the 3,200 K and 5,500 K balance points are Kodak’s.

A Kelvin number tells a person reading the prompt exactly what you meant. Pair it with a plain color word, and mix sources on purpose: warm lamps in a blue-hour scene read as evening. Bounced light picks up the color of whatever it bounced off, so a green wall gives a green fill.

Light by product type

Product	What goes wrong	Light that works
Clear glass and liquids	The glass disappears, or reflects the whole studio	Light from behind or diagonally behind; black or white cards at the sides for edges. See AI drink photos.
Polished metal and jewelry	Shiny surfaces mirror the room and every stray light	Large, diffused sources and strip lights, which the metal reflects as long, soft-edged highlights. See shoes, jewelry and accessories.
Matte packs and labels	Glare across the label, or a flat, lifeless box	Soft key at 45 degrees, bounce on the shadow side, no light straight on the label
Food	Looks flat and dry	Side or back light, so crumbs, gloss and steam cast shadows and catch highlights
Fabric	The weave and texture vanish	Raking light at a low angle. See how to show fabric and fit.
Creams and swatches	Texture reads as a smear	Low raking light so peaks and ridges throw small shadows

Questions people also ask

Do AI models understand Kelvin numbers?: Treat a Kelvin value as a hint and add the plain color word, as in "warm tungsten, about 3200K". None of the prompting guides from Google, OpenAI or Black Forest Labs that we read explains how their models handle Kelvin values, so check the render.
Can I name a classic setup, such as three-point lighting?: Yes. Google’s prompting guide for Nano Banana uses "three-point softbox setup" as an example. Add what the setup should do to the product, because the same three lights can be placed many ways.
Why does my product look like it is floating?: It has no contact shadow. Say where the shadow falls, for example "a soft contact shadow where the base meets the table". See how to make AI product photos look real.

Where Overs fits

In Overs, the visual style step records the light a brand’s own photos use, along with its colors, lens and grain, before any prompt is written.

Free for 40 photos a month. The AI that makes the photos is billed separately, on your own key, with no markup from Overs.

Start free How it works

Sources

Checked on September 24, 2026. Prices, specs and rules change; follow the links for the current versions.