Yellow1
yellow1 · #FFFF00
HEX
#FFFF00
RGB
rgb(255, 255, 0)
CMYK
cmyk(0%, 0%, 100%, 0%)
HSL
hsl(60, 100%, 50%)
LAB
lab(97.1, -21.6, 94.5)
What is Yellow1?
Yellow1 is the yellow1 reference in the X11 named colors. Its sRGB value is #FFFF00 (rgb 255, 255, 0). It sits in the yellow family. Historical X Window System color names — the numbered 1-4 lightness variants of the classic xorg-server rgb.txt palette. See disclaimer for accuracy and trademark notes.
Accessibility
WCAG 2.1 contrast checks for Yellow1 as a background.
Black text on this color
White text on this color
Shades, tints & tonal scale of Yellow1
An 11-step tonal scale derived from Yellow1 (#FFFF00). Click any swatch to copy its HEX. Use these as a starting point for design tokens, hover states, and disabled states in a design system.
50
#FFFFEB
#FFFFEB
100
#FFFFD6
#FFFFD6
200
#FFFFAD
#FFFFAD
300
#FFFF80
#FFFF80
400
#FFFF40
#FFFF40
500
#FFFF00
#FFFF00
600
#D9D900
#D9D900
700
#A6A600
#A6A600
800
#737300
#737300
900
#404000
#404000
950
#1F1F00
#1F1F00
Lighter tints (mixed with white)
15%
#FFFF6C
30%
#FFFF95
45%
#FFFFB3
60%
#FFFFCB
75%
#FFFFE1
Darker shades (mixed with black)
15%
#EDED00
30%
#DADA00
45%
#C4C400
60%
#AAAA00
75%
#898900
Color harmonies for Yellow1
Classic color-theory harmonies derived from rotating the hue of Yellow1. Use these to build accent palettes, brand systems, and accessible UI color pairings.
Complementary
180° opposite — strongest contrast
#FFFF00
#FFFF00
#0000FF
#0000FF
Triadic
Three colors 120° apart
#FFFF00
#FFFF00
#00FFFF
#00FFFF
#FF00FF
#FF00FF
Analogous
Two neighbors ±30° on the wheel
#FF8000
#FF8000
#FFFF00
#FFFF00
#80FF00
#80FF00
Split-complementary
Base + two colors flanking its complement
#FFFF00
#FFFF00
#007FFF
#007FFF
#7F00FF
#7F00FF
Tetradic
Two complementary pairs
#FFFF00
#FFFF00
#00FF00
#00FF00
#0000FF
#0000FF
#FF00FF
#FF00FF
Square
Four colors evenly spaced 90° apart
#FFFF00
#FFFF00
#00FF80
#00FF80
#0000FF
#0000FF
#FF0080
#FF0080
Yellow1 in every color space
Full conversion of Yellow1 across the color spaces designers and developers actually use — including OKLCH (the perceptually-uniform space that powers Tailwind v4 and CSS Color Module Level 4) and HWB.
HEX
#FFFF00
RGB
rgb(255, 255, 0)
CMYK
cmyk(0%, 0%, 100%, 0%)
HSL
hsl(60, 100%, 50%)
HSV
hsv(60, 100%, 100%)
HWB
hwb(60 0% 0%)
CIE Lab
lab(97.1 -21.6 94.5)
OKLCH
oklch(96.8% 0.211 109.8)
XYZ (D65)
xyz(77.00, 92.78, 13.85)
Copy-ready code for Yellow1
Drop-in snippets for CSS, Tailwind, Sass, iOS Swift, and Android XML. Click the copy button on any snippet to put it on your clipboard.
CSS
color: #FFFF00;
background-color: #FFFF00;CSS variable
:root {
--color-yellow1: #FFFF00;
}Tailwind config
// tailwind.config.js
colors: {
'yellow1': '#FFFF00',
}Sass
$color-yellow1: #FFFF00;Swift UIColor
UIColor(red: 1.000, green: 1.000, blue: 0.000, alpha: 1.0)Android XML
<color name="yellow1">#FFFF00</color>Closest match in every color system
The nearest Yellow1 equivalent in every other color system on this site, ranked by ΔE2000 perceptual distance. Useful when translating between design-system, web-standard, and industrial color references.
Closest in X11 named colors
Top 6 ΔE2000-closest entries within the same collection.
Closest Pantone matches
Top 6 ΔE2000-closest Pantone references. Cross-system matching is approximate — see disclaimer.
Closest RAL Classic matches
Top 6 ΔE2000-closest RAL Classic references for industrial coating cross-reference.
RAL 1026
#FFFF00
Luminous yellow
RAL 1018
#F8F32B
Zinc yellow
RAL 1016
#EDFF21
Sulfur yellow
RAL 1021
#F3DA0B
Rape yellow
RAL 1023
#FAD201
Traffic yellow
RAL 1017
#F5D033
Saffron yellow
FAQ about Yellow1
What is the HEX code for Yellow1?
Yellow1 (yellow1) has the HEX code #FFFF00. In RGB it is rgb(255, 255, 0), and in CMYK it is cmyk(0%, 0%, 100%, 0%).
What is the OKLCH value of Yellow1?
Yellow1 converts to oklch(0.968 0.211 109.8). OKLCH is the perceptually uniform color space used by Tailwind v4 and CSS Color Module Level 4.
Is Yellow1 accessible for body text?
Used as a background, Yellow1 has a contrast ratio of 19.56:1 with black text and 1.07:1 with white text. WCAG 2.1 AA requires 4.5:1 for normal text. The current recommendation is to use black text and verify in real UI context.
What is the closest Pantone to Yellow1?
The closest Pantone reference to Yellow1 by ΔE2000 perceptual distance is Pantone Process Yellow C (#FFEF00). Cross-system Pantone matching is approximate; for color-critical print work, verify with a physical Pantone guide.
What is the closest RAL color to Yellow1?
The closest RAL Classic reference to Yellow1 by ΔE2000 distance is RAL 1026 (Luminous yellow, #FFFF00). RAL is a German industrial coating standard commonly used for paint, powder coat, and architectural specification.
What is the complementary color of Yellow1?
The complementary color (180° opposite on the HSL color wheel) of Yellow1 is #0000FF. Use it for high-contrast accents, error states, or call-to-action pairings.
Data provenance & source
X11 named colors (xorg rgb.txt)
The historical X11 color name list shipped in the xorg-server rgb.txt file. Roughly 550 entries covering classic computing color names like 'PapayaWhip', 'MediumAquamarine', and 'DarkSlateGray'. Many CSS named colors originate here. Use as a reference for legacy and creative color names. Most modern CSS implementations accept these names directly.
- Source type
- derived
- Confidence
- high
- License
- MIT/X11 license (X Consortium)
- Last reviewed
- 2026-05-24
Workflow tags
X11 colors are sRGB digital values from a 1980s color system. For print, convert to a process-appropriate color and proof against substrate.