The first three seconds on the shelf: color in packaging

Short answer

In a product line, variants are told apart by color while family consistency is preserved, because packaging has two layers: the logo, the layout, the structure, and the core colors are the fixed layer that stays the same across every variant; only a specific area — a stripe, a label, or a section of the background, for example — is the variable layer that changes color by variant. When variant colors are kept close in lightness and saturation and only their hues are separated, the line looks like a family on the shelf, and the variants can still be told apart. How a color actually looks on the shelf depends on the packaging material and the store's lighting; cardboard, metal, and plastic show the same ink differently, and a design isn't finished until it has been tested under that lighting.

Color's three jobs in packaging

On the shelf, a package's color does three jobs at once. First, it signals the category: the category color codes covered in PZ-04 tell a customer "this is milk," "this is detergent," at a glance. Second, it carries the brand: the primary brand color covered in GT-04 is the brand's signature in the clutter of the shelf. Third, it separates the variant: a brand's plain, strawberry, and chocolate variants, or its sensitive-skin, normal-skin, and dry-skin products, need to be told apart quickly.

These three jobs sometimes conflict. The category color, the brand color, and the variant color have to share the same small surface. A good packaging system gives each of the three its own place and its own priority. The research on how color affects noticing and selection on the shelf is covered in PZ-03; here we're looking at the system a designer builds.

Variant coding and family consistency

The question on the lesson card is the basic question of packaging systems: in a product line, how are variants told apart by color while family consistency is preserved?

The first part of the solution is splitting the packaging into a fixed layer and a variable layer. The fixed layer is the logo's position and color, the typefaces, the layout, the shape of the package, and the brand's core colors; it stays the same across every variant and makes the line a family. The variable layer, by contrast, is only a specific area: a stripe, a cap, a section of the background, or an image that illustrates the flavor. The variant's color changes only within this area.

The second part of the solution is choosing the variant colors as a family. In a perceptually organized space like OKLCh, covered in BI-24, when variant colors are kept close in lightness and chroma and only their hue angles are separated, the colors form a set that "speaks the same language": none of them looks much brighter or much darker than the others, but their hues still keep them apart. If, instead, one variant is chosen as neon green, another as pale beige, and another as dark maroon, the line looks scattered on the shelf no matter how consistent the fixed layer is.

The third part is the number of variants. The number of colors that can be told apart comfortably is limited. As the number of variants grows, the colors move closer together and start to blur. At that point, color needs extra cues: the variant's name is printed large and legible, an image showing the flavor is added, or an icon or pattern is used. These extra cues are also necessary for customers with color vision deficiency; as covered in BI-12, a customer who has trouble telling red from green can mix up two variants that are separated by color alone.

Flavors and expectations

Variant colors are often derived from the flavor itself: red or pink for strawberry, yellow for lemon, green for mint, brown for cocoa. These pairings also set the customer's expectation. Charles Spence's review of the psychological effects of food color looks at how color shapes taste expectation and perception.

Some flavors, though, have no natural color at all: salt, vinegar, cheese, or onion. In that case, the color code settles in by convention, and the convention can differ from brand to brand. In the United Kingdom, the Walkers brand sells its cheese-and-onion crisps in blue packets and its salt-and-vinegar crisps in green ones; many other brands do the reverse. This mismatch is often brought up with bewilderment in the United Kingdom, and it's a good example of a variant color coming from habit rather than nature.

This example shows that variant codes can also become a norm within a category. When designing a new line, checking whether the variant colors conflict with the colors competitors use for the same flavors keeps a customer from picking up the wrong product off the shelf.

Material changes color

The same color definition looks different when it's printed on different packaging materials. A design may be finished on screen, but on the shelf, the color lives on the material.

Uncoated cardboard absorbs ink; colors look more matte, darker, and less saturated. Coated cardboard and glossy surfaces keep the ink on the surface; colors look more vivid, but the gloss can reflect light and make the package harder to read from certain angles. Brown surfaces like kraft paper pull every color printed on them toward their own hue.

Metal and clear plastic carry a separate problem. Printing inks are often semi-transparent; they look correct on white paper because the paper's white reflects light back. On a clear film, though, the color of the product behind it shows through the ink, and on a metal surface, the metal's shine shows through it. That's why, in package printing, an opaque white layer is printed under the colors wherever it's needed.

White underprint can also be a design tool. On a metal can, white is left off certain areas and the colored ink goes directly onto the metal; those areas take on a metallic, shiny look. A single package can carry both flat and metallic colors, achieved only by where the white layer is and isn't printed. Printing itself — how four-color process printing and spot colors work — is the subject of EK-08.

The different parts of a line are often made from different materials: the outer box might be cardboard, the bottle plastic, the cap metal. Because the customer sees these together, the same variant color has to be perceived as "the same color" across all three materials. That means a separate color definition and a tolerance for each material: printed samples are measured, and their distance from the target color is calculated with the color difference formulas covered in BI-20. A batch that falls outside the set tolerance is caught by measurement before it's noticed by eye. That's how the line stays a single family from the production line to the shelf.

Retail lighting

The last thing a package's color meets is the store's lighting. Stores use lighting at different color temperatures and different color fidelity; a warm light brings out reds and oranges and can wash out blues, and light with low color fidelity can shift some colors in unexpected ways. Metamerism, covered in BI-15, turns into a concrete problem here: two variant colors that look identical in the design studio can separate from each other under store lighting, or conversely, blend into each other.

That's why a good packaging process also tests the design once on the actual packaging material, under lighting similar to the target store's. The printing world has defined common conditions for evaluating printed work under a standard light; but on the shelf, the package will be seen not under that standard light but under the store's own lighting. Both have to be tested.

Step by step: a packaging color system

The first step is defining the fixed layer: the logo, the layout, the shape, and the core colors. The second step is deciding the location and size of the variable layer. The third step is choosing the variant colors as a set in a space faithful to the eye's differences, like OKLCh, with lightness and chroma kept close and only hues separated. The fourth step is comparing these colors against the colors competitors use for the same variants. The fifth step is adding cues beyond color — a name, an image, an icon. The sixth step is printing the design onto the actual material, with white underprint where needed, and testing it. The seventh step is testing the printed sample under lighting similar to the store's, with all the variants lined up side by side.

Example — when the product's color is a skin tone

For some products, the color the packaging needs to show is the product's own color, and that color is a skin tone: adhesive bandages, foundations, concealers, hosiery. For these products, the packaging doesn't just separate a variant; it has to let the customer pick the product closest to their own skin.

For many years, most adhesive bandage brands offered a single light pink-beige tone as "skin color"; like the "skin color" crayon name covered in TK-18, this was a choice that centered a single skin tone. Today, some brands offer separate tones for different skin tones. The Band-Aid brand's OURTONE line offers adhesive bandages for brown skin tones in light, medium, and deep shades, coded BR45, BR55, and BR65.

A line like this puts every question in this lesson to the packaging designer at once. The variants — the skin tones — have to be clearly told apart while family consistency is preserved: the fixed layer stays the same while the product-color swatch on the package changes. This swatch has to sit as close as possible to the real product's color on the printed package; ink, material, and white underprint all directly affect how close it gets. Retail lighting enters the picture too: under warm store lighting, the swatches can look warmer than they are, and a customer can match their own skin to the wrong tone. Printing the tone's name and code clearly next to the swatch helps the customer choose the right color despite the lighting.

Common misconception

Summary

1. Color in packaging signals the category, the brand, and the variant all at once; family consistency is preserved by a fixed layer that stays the same across every variant and a variant color that changes only in a specific area.
2. When variant colors are chosen with close lightness and chroma and separate hues, the line looks like a family; as the number of variants grows, and for customers with color vision deficiency, extra cues such as a name, an image, or an icon become necessary.
3. Material and retail lighting change color; on clear and metal surfaces, white underprint gives colors a neutral base, and a design is tested on the actual material and under store lighting. If the product's color is a skin tone, the accuracy of the swatch determines whether the customer can pick the product that matches their own skin.

Test yourself

1. (Easy) What does the fixed layer cover in a packaging system?
2. (Easy) Why is white underprint necessary?
3. (Medium) In a product line, how are variants told apart by color while family consistency is preserved?
4. (Medium) What does the Walkers example show about variant colors?
5. (Hard) Why does color coding fall short as the number of variants grows, and what can be done about it?
6. (Hard) Why is the color swatch a critical element on the packaging of a line that sells adhesive bandages or foundation in different skin tones, and what factors affect it?

Answers

1. The elements that stay the same across every variant: the logo, the typefaces, the layout, the shape of the package, and the brand's core colors ("Variant coding and family consistency").
2. Printing inks are often semi-transparent; on clear film or a metal surface, the color behind it or the surface's shine shows through the ink. White underprint gives the colors a neutral base similar to the white of paper ("Material changes color").
3. Packaging is split into a fixed layer and a variable layer; the logo, layout, shape, and core colors stay the same across every variant, and only a specific area changes color by variant. When variant colors are kept close in lightness and chroma and only their hues are separated, the line looks like a family ("Variant coding and family consistency").
4. That for flavors with no natural color, the variant color comes from habit rather than nature and can differ from brand to brand; and that a new line needs to check whether its variant colors conflict with competitors' ("Flavors and expectations").
5. The number of colors that can be told apart comfortably is limited; as variants increase, the colors move closer together and blur. The variant's name is printed large, and a flavor image, icon, or pattern is added; these extra cues are also necessary for customers with color vision deficiency ("Variant coding and family consistency").
6. The swatch is the only visual cue that lets the customer pick the product closest to their own skin. Ink, material, white underprint, and store lighting all change how the swatch looks; under warm light, the swatch can look warmer than it is. Printing the tone's name and code clearly helps the customer choose correctly ("Example — when the product's color is a skin tone").

Sources

• Tomerlin, D., Valdec, D., Tomiša, M., and Vusić, D., "The impact of underlying opaque white coating parameters on flexographic print quality," Applied Sciences 13(15): 8575, 2023.
• Spence, C., "On the psychological impact of food colour," Flavour 4: 21, 2015.
• Vice, "The Walkers Crisps Conspiracy That Has People Convinced We're in an Alternate Reality."
• Band-Aid Brand, "OURTONE Adhesive Bandages," product page.

Next step

GT-06 moves from the handheld distance of packaging to the distance of the street: it covers how a roadside billboard gets read in a few seconds, how differently that works from an image scrolling on a palm-sized screen, two strong schools of poster history from Hungary and Switzerland, and how a digital design can lose its color when it's printed. GT-07 discusses who makes the "color of the year" announcements made every year and how, their marketing function, and the risks of following these announcements blindly.