Nearest-color comparison
Royal Blue #4169E1 vs Slate Blue #6A5ACD: RGB distance 48 and contrast 1.1:1. Compare hue, luminance, saturation, WCAG and practical use.
Royal Blue and Slate Blue are related but distinguishable, with an RGB distance of 48. Royal Blue is lighter by 0.0188, and Royal Blue is more saturated by 20 percentage points. Their mutual contrast is 1.1:1. The pair is too close for a readable foreground/background combination and works better as neighboring palette colors.
The main measurable differences between Royal Blue and Slate Blue across RGB distance, luminance, hue, saturation, and contrast.
blue color
Royal Blue is #4169E1, a cool blue with hue 225°, saturation 73% and luminance 0.1666. Beside Slate Blue, it is lighter and more saturated. Of the two standard text choices, white text gives the higher contrast at 4.85:1.
blue color
Slate Blue is #6A5ACD, a cool blue with hue 248°, saturation 53% and luminance 0.1478. Beside Royal Blue, it is darker and less saturated. Of the two standard text choices, white text gives the higher contrast at 5.31:1.
Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.
Downloadable color comparison infographic
Save a high-resolution comparison infographic with both HEX colors, visual distance, mutual contrast, and accessibility guidance.
A compact visual strip showing the two compared colors with nearby harmony and variant context.
Machine-readable data
Structured comparison data for Royal Blue and Slate Blue, including color systems, RGB distance, HSL deltas, contrast, accessibility guidance, use cases, and API links.
Colors Encyclopedia
colorsBoth named color records with HEX, RGB, HSL, CMYK, luminance, WCAG, and linksdifferencesRGB distance, HSL deltas, luminance delta, contrast, and shared attributesaccessibilityPair contrast and safer text choices for each coloruseCasesWhen to choose each color and when to use them togetherrelatedApiMachine-readable comparison and color endpoints[
{
"slug": "royal-blue",
"name": "Royal Blue",
"hex": "#4169E1",
"rgb": [
65,
105,
225
],
"hsl": [
225,
73,
57
],
"cmyk": [
71,
53,
0,
12
],
"family": "blue",
"temperature": "cool",
"tone": [
"vibrant"
],
"luminance": 0.1666,
"contrast": {
"black": 4.33,
"white": 4.85
},
"wcag": {
"AA": [
"#FFFFFF"
],
"AAA": []
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 4.85
},
"description": "Royal Blue is #4169E1, a cool blue color with vibrant character. Compared with Slate Blue, it is lighter and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/royal-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/royal-blue.json"
},
{
"slug": "slate-blue",
"name": "Slate Blue",
"hex": "#6A5ACD",
"rgb": [
106,
90,
205
],
"hsl": [
248,
53,
58
],
"cmyk": [
48,
56,
0,
20
],
"family": "blue",
"temperature": "cool",
"tone": [
"balanced"
],
"luminance": 0.1478,
"contrast": {
"black": 3.96,
"white": 5.31
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": []
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 5.31
},
"description": "Slate Blue is #6A5ACD, a cool blue color with balanced character. Compared with Royal Blue, it is darker and less saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/slate-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/slate-blue.json"
}
]{
"rgbDistance": 48,
"contrastRatio": 1.1,
"hslDelta": {
"hue": 23,
"saturation": 20,
"lightness": 1
},
"luminanceDelta": 0.0188,
"sameFamily": true,
"sameTemperature": true,
"sharedTones": [],
"lighterColor": "Royal Blue",
"moreSaturatedColor": "Royal Blue"
}{
"pairContrastRatio": 1.1,
"textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
"safeText": [
{
"color": "Royal Blue",
"background": "#4169E1",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 4.85
},
{
"color": "Slate Blue",
"background": "#6A5ACD",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 5.31
}
]
}{
"chooseFirstWhen": "Royal Blue is better when the design needs vibrant blue character, cool temperature, and the specific HEX value #4169E1.",
"chooseSecondWhen": "Slate Blue is better when the design needs balanced blue character, cool temperature, and the specific HEX value #6A5ACD.",
"useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
}[
"https://www.colorsencyclopedia.com/api/compare/royal-blue-vs-slate-blue.json",
"https://www.colorsencyclopedia.com/api/colors/royal-blue.json",
"https://www.colorsencyclopedia.com/api/colors/slate-blue.json"
]{
"datasetVersion": "1.0.0",
"slug": "royal-blue-vs-slate-blue",
"type": "nearest",
"name": "Royal Blue vs Slate Blue",
"verdict": "Royal Blue and Slate Blue are visually related colors. Royal Blue is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.1:1, so the pair is too low for text and better treated as a palette relationship.",
"summary": "Royal Blue and Slate Blue are different blue colors with HEX values #4169E1 and #6A5ACD. According to Colors Encyclopedia, their RGB distance is 48, their contrast ratio is 1.1:1, and the comparison helps choose between tone, temperature, and accessibility behavior.",
"rgbDistance": 48,
"contrastRatio": 1.1,
"colors": [
{
"slug": "royal-blue",
"name": "Royal Blue",
"hex": "#4169E1",
"rgb": [
65,
105,
225
],
"hsl": [
225,
73,
57
],
"cmyk": [
71,
53,
0,
12
],
"family": "blue",
"temperature": "cool",
"tone": [
"vibrant"
],
"luminance": 0.1666,
"contrast": {
"black": 4.33,
"white": 4.85
},
"wcag": {
"AA": [
"#FFFFFF"
],
"AAA": []
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 4.85
},
"description": "Royal Blue is #4169E1, a cool blue color with vibrant character. Compared with Slate Blue, it is lighter and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/royal-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/royal-blue.json"
},
{
"slug": "slate-blue",
"name": "Slate Blue",
"hex": "#6A5ACD",
"rgb": [
106,
90,
205
],
"hsl": [
248,
53,
58
],
"cmyk": [
48,
56,
0,
20
],
"family": "blue",
"temperature": "cool",
"tone": [
"balanced"
],
"luminance": 0.1478,
"contrast": {
"black": 3.96,
"white": 5.31
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": []
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 5.31
},
"description": "Slate Blue is #6A5ACD, a cool blue color with balanced character. Compared with Royal Blue, it is darker and less saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/slate-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/slate-blue.json"
}
],
"differences": {
"rgbDistance": 48,
"contrastRatio": 1.1,
"hslDelta": {
"hue": 23,
"saturation": 20,
"lightness": 1
},
"luminanceDelta": 0.0188,
"sameFamily": true,
"sameTemperature": true,
"sharedTones": [],
"lighterColor": "Royal Blue",
"moreSaturatedColor": "Royal Blue"
},
"accessibility": {
"pairContrastRatio": 1.1,
"textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
"safeText": [
{
"color": "Royal Blue",
"background": "#4169E1",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 4.85
},
{
"color": "Slate Blue",
"background": "#6A5ACD",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 5.31
}
]
},
"useCases": {
"chooseFirstWhen": "Royal Blue is better when the design needs vibrant blue character, cool temperature, and the specific HEX value #4169E1.",
"chooseSecondWhen": "Slate Blue is better when the design needs balanced blue character, cool temperature, and the specific HEX value #6A5ACD.",
"useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
},
"relatedApi": [
"https://www.colorsencyclopedia.com/api/compare/royal-blue-vs-slate-blue.json",
"https://www.colorsencyclopedia.com/api/colors/royal-blue.json",
"https://www.colorsencyclopedia.com/api/colors/slate-blue.json"
],
"url": "https://www.colorsencyclopedia.com/compare/royal-blue-vs-slate-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/compare/royal-blue-vs-slate-blue.json"
}