How can I tell if a paint color has warm or cool undertones?
Visual Comparison
Place a sample of the paint next to a pure white piece of paper or a known warm (like a true red) and cool (like a true blue) color. The undertone will become more obvious by contrast.
Squint at the sample—this reduces detail and makes the overall cast easier to see. If it looks yellowish or reddish, it's warm; if it looks bluish or greenish, it's cool.
You can also hold the sample against different wall colors or fabrics to see how it shifts.
Use Lighting and Tools
Natural daylight (around noon) is the most neutral light for judging undertones. Incandescent bulbs enhance warm tones, while fluorescent and LED can enhance cool tones.
Paint companies often label colors as warm or cool, but these labels can be subjective. Trust your own eyes in your space.
Some brands offer undertone guides or apps, but they are not always accurate—use them as a starting point only.
- Compare the sample to a pure white and to known warm/cool colors.
- Squint to see the overall cast.
- View in natural daylight, not just artificial light.
- Check how the color looks next to your flooring and furniture.
Common mistakes
- Judging undertones under yellow incandescent light, which can make cool colors look warm.
- Relying solely on the color name or label—'greige' can be warm or cool.
- Forgetting that undertones can shift depending on adjacent colors.
