Underground (PPU18-02)
A warm, dark charcoal-brown. Deeper than Off Broadway, lighter than Granite Boulder. The warm brown gives it an earthy, organic quality at a very dark depth.
About Behr Underground
Underground (PPU18-02) is a gray from Behr's collection with an LRV of 10 and warm dark charcoal undertones. A warm, dark charcoal-brown. Deeper than Off Broadway, lighter than Granite Boulder. The warm brown gives it an earthy, organic quality at a very dark depth.
At an LRV of just 10, Underground is a dark, dramatic color that absorbs most of the light that hits it. This makes it perfect for creating bold, moody statements on accent walls, front doors, shutters, and exterior trim. It commands attention and creates a striking contrast with white or light-colored trim. Use it where you want real visual impact. In full room applications, generous lighting and light-colored furnishings prevent the space from feeling oppressive.
Light Reflectance Value (LRV)
Underground has an LRV of 10, placing it in the dark range on the 0-to-100 scale. LRV measures the percentage of visible light a color reflects. A pure black has an LRV of 0 and a pure white has an LRV of 100. Understanding a color's LRV helps you predict how it will feel in your space: higher LRV means brighter and more spacious, lower LRV means cozier and more intimate.
Undertone Analysis
Underground has warm dark charcoal undertones. Undertones are the subtle background colors that become visible in different lighting conditions. Even colors that look "neutral" in the store will reveal their undertones once they are on your walls and interacting with natural light, artificial light, and the colors around them.
A warm, dark charcoal-brown. Deeper than Off Broadway, lighter than Granite Boulder. The warm brown gives it an earthy, organic quality at a very dark depth. Warm undertones like these pair naturally with other warm elements: honey-toned wood floors, brass and gold hardware, cream-colored textiles, and warm-toned furnishings. They can clash with strongly cool elements like icy blue accents or chrome fixtures, though the effect depends on the strength of the undertone.
Lighting Behavior
In bright light, the warm brown undertone is visible. In dim rooms, it reads as a warm near-black. A strong, earthy dark neutral.
Every paint color looks different depending on the light source in your room. South-facing rooms get warm, direct sunlight that brings out yellow and warm undertones. North-facing rooms get cool, indirect light that emphasizes blue and gray undertones. East-facing rooms are bright and warm in the morning, cooler in the afternoon. West-facing rooms are the opposite: cool morning, warm afternoon. Incandescent and warm LED bulbs push colors warmer, while cool-white LEDs and fluorescent tubes push colors cooler. To avoid surprises, always test Underground with a physical sample on your actual wall, and observe it at different times of day before committing.
Best Rooms for Underground
Behr recommends Underground for: accent wall, front door, cabinets, exterior trim, shutters.
On kitchen and bathroom cabinets, Underground offers a fresh, clean look. Cabinet colors are seen up close and under task lighting, so the undertones matter even more than on walls. On an accent wall, Underground creates a focal point that draws the eye and adds visual depth to the room. Pair it with a lighter color on the remaining walls for the best contrast. On a front door, Underground makes a strong first impression. Front door colors are seen in full outdoor light, so choose a finish with some sheen (satin or semi-gloss) for durability and visual impact.
Closest Matches in Other Brands
Find the closest equivalent to Behr Underground from other paint brands. Matches are calculated using Delta E (CIE2000), the industry standard for measuring perceptual color difference.
Sherwin Williams Matches
Peppercorn is close. Both are warm, dark charcoals.
View all Sherwin Williams matches →Benjamin Moore Matches
Iron Mountain is greener. Underground is browner.
View all Benjamin Moore matches →Coordinating Colors
These colors pair beautifully with Underground for a cohesive palette. Use them for trim, accents, adjacent rooms, or furniture to create a well-designed space.
Frequently Asked Questions
The closest Sherwin Williams match for Behr Underground is Peppercorn (SW 7674) with a Delta E of 3.8, which rates as a "good match" match. Peppercorn is close. Both are warm, dark charcoals. A Delta E under 2 means most people cannot tell the colors apart, while 2 to 4 means the difference is subtle.
Underground has warm dark charcoal undertones. A warm, dark charcoal-brown. Deeper than Off Broadway, lighter than Granite Boulder. The warm brown gives it an earthy, organic quality at a very dark depth. Undertones become most visible when the color is on a large surface like a wall, and they shift depending on the light source in your room. Always test with a physical sample in your specific space to see how the undertones interact with your lighting, flooring, and furnishings.
Underground (PPU18-02) has a Light Reflectance Value (LRV) of 10, which puts it in the dark range. LRV measures the percentage of light a color reflects on a scale from 0 (pure black) to 100 (pure white). At 10, this is a darker color that creates a cozy, intimate atmosphere. Pair it with bright white trim for the best contrast.
Underground leans warm. The warm dark charcoal undertones give it a cozy, inviting quality. It pairs naturally with other warm elements like wood tones, brass hardware, and cream textiles. In north-facing rooms, the warmth is especially welcoming.
Color data sourced from manufacturer specifications. Match calculations use Delta E (CIE2000) computed from Lab color space conversion. Last reviewed: March 22, 2026.