Why does some blue work as a calming background while other blues seem cold and off-putting? Why does a certain orange make a great accent while another feels too loud with the same text? Warm/cool colors aren’t just words for a color wheel, but also impact how well colors complement each other, how much a color grabs attention, and whether a design feels balanced or slightly off-putting. Warm colors usually go from red to orange to yellow, while cool colors usually go from blue to green to purple. Easy enough until you’re actually picking colors for an image. A green can look warm with more yellow, and cool with more blue. A red can look warm with more orange, and cool when it leans more toward a magenta. If a beginner picks colors that should go together, but the resulting design doesn’t look great, a warm/cool shift within the hue can be to blame.
A practical warm/cool color test is by looking at colors on a neutral color background. Take warm/beige, cool/gray, yellow/green, blue/green, coral, and magenta and place them in different contexts within one layout, such as a simple card or poster design. Don’t look just at the colors in the swatch panel, look at them behind a heading, next to body text, and inside a button. A particular color might feel better with warm colors than cool colors, or vice versa. Some colors move forward visually and some appear to recede. A warm accent might be too forward, or a cool background might not look great with a really cool color behind it if it’s too bright.
A lot of warm/cool problems show up in a design that doesn’t have an overall warm/cool feeling. A design might have a warm/cream background, a cool/blue heading, a yellow-green icon, and a pink button. Individually, the colors look good together, but the warm/cool colors might give it a scattered feeling. The design might not be seen as soft/cool, fresh/cool, energetic/warm, serious/cool, or fun/warm. The solution isn’t necessarily to remove the color that doesn’t seem like the overall warm or cool color. A design can be mostly warm with a neutral/cool, and cool with a single warm accent.
Try creating two designs with the same structure. Use mostly warm colors in one and mostly cool colors in the other. For example, warm: cream background, muted orange accent, soft brown text color, and one darker warm neutral. Cool: background color is pale blue/gray, accent color is muted teal, body text color is a deep navy, and one light cool neutral. Use the exact same font size, button size, and spacing for both. This lets you check the warm/cool feel before changing anything else. This can help train your eye to first look for warm/cool before assessing whether the colors you picked are good to start with.
If the warm/cool color test passes, then check contrast and brightness values. Maybe a warm color is too light to use white body text on it. Maybe a cool color isn’t different enough from a gray background. If the color choice looks great but the text isn’t quite right, check brightness value before worrying about warm/cool. If the colors feel too noisy, check the saturation level and maybe remove one warm/cool color to try instead of adding another one to the mix. Warm/cool color can help guide where the eye goes, but brightness value and saturation level are more important to decide if the colors are readable and can be used effectively.
When you do a color check, ask yourself this final question: Do warm or cool colors take the lead? Look at the background color, body text, accent color, and other swatch colors. If warm and cool colors are mixed equally throughout, the design can look restless. If one feels like it takes the lead and the other plays a supporting role, the colors are easier to use. Next time you do a color check, instead of just seeing if colors go well together, think about which colors you picked look warm/cool and which colors should lead the viewer’s eye first.