Nearest-color comparison

Cobalt Blue vs Signal Blue

Cobalt Blue and Signal Blue are different blue colors with HEX values #0047AB and #0057B8. According to Colors Encyclopedia, their RGB distance is 20.6, their contrast ratio is 1.23:1, and the comparison helps choose between tone, temperature, and accessibility behavior.

Cobalt Blue and Signal Blue are very close colors. Signal Blue is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.23:1, so the pair is too low for text and better treated as a palette relationship.

Differences Use cases Accessibility JSON

Cobalt Blue#0047AB

Signal Blue#0057B8

Quick Difference Summary

The main measurable differences between Cobalt Blue and Signal Blue across RGB distance, luminance, hue, saturation, and contrast.

RGB distance20.6

Pair contrast1.23:1

Luminance delta0.0283

Hue delta3 deg

Lighter colorSignal Blue

More saturatedCobalt Blue

Side-by-Side Color Profiles

blue color

Cobalt Blue

Cobalt Blue is #0047AB, a cool blue color with jewel tone character. Compared with Signal Blue, it is darker and similar in saturation. Use it for interfaces, brand systems, and technical design, with white text as the safer foreground option.

HEX#0047AB RGB0, 71, 171 HSL215, 100, 34 CMYK100, 58, 0, 33 Luminance0.0745 Best textwhite text

Color page WCAG HEX atlas

blue color

Signal Blue

Signal Blue is #0057B8, a cool blue color with vibrant and jewel tone character. Compared with Cobalt Blue, it is lighter and similar in saturation. Use it for industrial design, safety systems, and hardware palettes, with white text as the safer foreground option.

HEX#0057B8 RGB0, 87, 184 HSL212, 100, 36 CMYK100, 53, 0, 28 Luminance0.1028 Best textwhite text

Color page WCAG HEX atlas

When to Use Cobalt Blue or Signal Blue

Choose Cobalt BlueCobalt Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #0047AB.

Choose Signal BlueSignal Blue is better when the design needs vibrant and jewel tone blue character, cool temperature, and the specific HEX value #0057B8.

Use togetherUse these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs.

Technical Comparison Table

PropertyCobalt BlueSignal Blue

HEX#0047AB#0057B8

RGB0, 71, 1710, 87, 184

HSL215, 100, 34212, 100, 36

CMYK100, 58, 0, 33100, 53, 0, 28

FamilyBlueBlue

TemperatureCoolCool

ToneJewel ToneVibrant, Jewel Tone

Luminance0.07450.1028

Black contrast2.49:13.06:1

White contrast8.43:16.87:1

Shared tonesJewel Tone

Accessibility and Contrast

Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.

Cobalt Bluewhite text - 8.43:1

Signal Bluewhite text - 6.87:1

Related Palette Strip

A compact visual strip showing the two compared colors with nearby harmony and variant context.

Cobalt Blue#0047AB

Signal Blue#0057B8

#0A70FF#0A70FF

#1482FF#1482FF

#AD6500#AD6500

#B86200#B86200

colorsBoth named color records with HEX, RGB, HSL, CMYK, luminance, WCAG, and links

differencesRGB distance, HSL deltas, luminance delta, contrast, and shared attributes

accessibilityPair contrast and safer text choices for each color

useCasesWhen to choose each color and when to use them together

relatedApiMachine-readable comparison and color endpoints

Structured sections

Colors

[
  {
    "slug": "cobalt-blue",
    "name": "Cobalt Blue",
    "hex": "#0047AB",
    "rgb": [
      0,
      71,
      171
    ],
    "hsl": [
      215,
      100,
      34
    ],
    "cmyk": [
      100,
      58,
      0,
      33
    ],
    "family": "blue",
    "temperature": "cool",
    "tone": [
      "jewel-tone"
    ],
    "luminance": 0.0745,
    "contrast": {
      "black": 2.49,
      "white": 8.43
    },
    "wcag": {
      "AA": [
        "#FFFFFF",
        "#F5F5F5"
      ],
      "AAA": [
        "#FFFFFF",
        "#F5F5F5"
      ]
    },
    "bestText": {
      "text": "#FFFFFF",
      "label": "white text",
      "ratio": 8.43
    },
    "description": "Cobalt Blue is #0047AB, a cool blue color with jewel tone character. Compared with Signal Blue, it is darker and similar in saturation. Use it for interfaces, brand systems, and technical design, with white text as the safer foreground option.",
    "url": "https://www.colorsencyclopedia.com/colors/cobalt-blue/",
    "apiUrl": "https://www.colorsencyclopedia.com/api/colors/cobalt-blue.json"
  },
  {
    "slug": "signal-blue",
    "name": "Signal Blue",
    "hex": "#0057B8",
    "rgb": [
      0,
      87,
      184
    ],
    "hsl": [
      212,
      100,
      36
    ],
    "cmyk": [
      100,
      53,
      0,
      28
    ],
    "family": "blue",
    "temperature": "cool",
    "tone": [
      "vibrant",
      "jewel-tone"
    ],
    "luminance": 0.1028,
    "contrast": {
      "black": 3.06,
      "white": 6.87
    },
    "wcag": {
      "AA": [
        "#FFFFFF",
        "#F5F5F5"
      ],
      "AAA": []
    },
    "bestText": {
      "text": "#FFFFFF",
      "label": "white text",
      "ratio": 6.87
    },
    "description": "Signal Blue is #0057B8, a cool blue color with vibrant and jewel tone character. Compared with Cobalt Blue, it is lighter and similar in saturation. Use it for industrial design, safety systems, and hardware palettes, with white text as the safer foreground option.",
    "url": "https://www.colorsencyclopedia.com/colors/signal-blue/",
    "apiUrl": "https://www.colorsencyclopedia.com/api/colors/signal-blue.json"
  }
]

Differences

{
  "rgbDistance": 20.6,
  "contrastRatio": 1.23,
  "hslDelta": {
    "hue": 3,
    "saturation": 0,
    "lightness": 2
  },
  "luminanceDelta": 0.0283,
  "sameFamily": true,
  "sameTemperature": true,
  "sharedTones": [
    "jewel-tone"
  ],
  "lighterColor": "Signal Blue",
  "moreSaturatedColor": "Cobalt Blue"
}

Accessibility

{
  "pairContrastRatio": 1.23,
  "textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
  "safeText": [
    {
      "color": "Cobalt Blue",
      "background": "#0047AB",
      "foreground": "#FFFFFF",
      "label": "white text",
      "ratio": 8.43
    },
    {
      "color": "Signal Blue",
      "background": "#0057B8",
      "foreground": "#FFFFFF",
      "label": "white text",
      "ratio": 6.87
    }
  ]
}

Use cases

{
  "chooseFirstWhen": "Cobalt Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #0047AB.",
  "chooseSecondWhen": "Signal Blue is better when the design needs vibrant and jewel tone blue character, cool temperature, and the specific HEX value #0057B8.",
  "useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
}

Related API

[
  "https://www.colorsencyclopedia.com/api/compare/cobalt-blue-vs-signal-blue.json",
  "https://www.colorsencyclopedia.com/api/colors/cobalt-blue.json",
  "https://www.colorsencyclopedia.com/api/colors/signal-blue.json"
]

Full JSON dataset

{
  "datasetVersion": "1.0.0",
  "slug": "cobalt-blue-vs-signal-blue",
  "type": "nearest",
  "name": "Cobalt Blue vs Signal Blue",
  "verdict": "Cobalt Blue and Signal Blue are very close colors. Signal Blue is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.23:1, so the pair is too low for text and better treated as a palette relationship.",
  "summary": "Cobalt Blue and Signal Blue are different blue colors with HEX values #0047AB and #0057B8. According to Colors Encyclopedia, their RGB distance is 20.6, their contrast ratio is 1.23:1, and the comparison helps choose between tone, temperature, and accessibility behavior.",
  "rgbDistance": 20.6,
  "contrastRatio": 1.23,
  "colors": [
    {
      "slug": "cobalt-blue",
      "name": "Cobalt Blue",
      "hex": "#0047AB",
      "rgb": [
        0,
        71,
        171
      ],
      "hsl": [
        215,
        100,
        34
      ],
      "cmyk": [
        100,
        58,
        0,
        33
      ],
      "family": "blue",
      "temperature": "cool",
      "tone": [
        "jewel-tone"
      ],
      "luminance": 0.0745,
      "contrast": {
        "black": 2.49,
        "white": 8.43
      },
      "wcag": {
        "AA": [
          "#FFFFFF",
          "#F5F5F5"
        ],
        "AAA": [
          "#FFFFFF",
          "#F5F5F5"
        ]
      },
      "bestText": {
        "text": "#FFFFFF",
        "label": "white text",
        "ratio": 8.43
      },
      "description": "Cobalt Blue is #0047AB, a cool blue color with jewel tone character. Compared with Signal Blue, it is darker and similar in saturation. Use it for interfaces, brand systems, and technical design, with white text as the safer foreground option.",
      "url": "https://www.colorsencyclopedia.com/colors/cobalt-blue/",
      "apiUrl": "https://www.colorsencyclopedia.com/api/colors/cobalt-blue.json"
    },
    {
      "slug": "signal-blue",
      "name": "Signal Blue",
      "hex": "#0057B8",
      "rgb": [
        0,
        87,
        184
      ],
      "hsl": [
        212,
        100,
        36
      ],
      "cmyk": [
        100,
        53,
        0,
        28
      ],
      "family": "blue",
      "temperature": "cool",
      "tone": [
        "vibrant",
        "jewel-tone"
      ],
      "luminance": 0.1028,
      "contrast": {
        "black": 3.06,
        "white": 6.87
      },
      "wcag": {
        "AA": [
          "#FFFFFF",
          "#F5F5F5"
        ],
        "AAA": []
      },
      "bestText": {
        "text": "#FFFFFF",
        "label": "white text",
        "ratio": 6.87
      },
      "description": "Signal Blue is #0057B8, a cool blue color with vibrant and jewel tone character. Compared with Cobalt Blue, it is lighter and similar in saturation. Use it for industrial design, safety systems, and hardware palettes, with white text as the safer foreground option.",
      "url": "https://www.colorsencyclopedia.com/colors/signal-blue/",
      "apiUrl": "https://www.colorsencyclopedia.com/api/colors/signal-blue.json"
    }
  ],
  "differences": {
    "rgbDistance": 20.6,
    "contrastRatio": 1.23,
    "hslDelta": {
      "hue": 3,
      "saturation": 0,
      "lightness": 2
    },
    "luminanceDelta": 0.0283,
    "sameFamily": true,
    "sameTemperature": true,
    "sharedTones": [
      "jewel-tone"
    ],
    "lighterColor": "Signal Blue",
    "moreSaturatedColor": "Cobalt Blue"
  },
  "accessibility": {
    "pairContrastRatio": 1.23,
    "textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
    "safeText": [
      {
        "color": "Cobalt Blue",
        "background": "#0047AB",
        "foreground": "#FFFFFF",
        "label": "white text",
        "ratio": 8.43
      },
      {
        "color": "Signal Blue",
        "background": "#0057B8",
        "foreground": "#FFFFFF",
        "label": "white text",
        "ratio": 6.87
      }
    ]
  },
  "useCases": {
    "chooseFirstWhen": "Cobalt Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #0047AB.",
    "chooseSecondWhen": "Signal Blue is better when the design needs vibrant and jewel tone blue character, cool temperature, and the specific HEX value #0057B8.",
    "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/cobalt-blue-vs-signal-blue.json",
    "https://www.colorsencyclopedia.com/api/colors/cobalt-blue.json",
    "https://www.colorsencyclopedia.com/api/colors/signal-blue.json"
  ],
  "url": "https://www.colorsencyclopedia.com/compare/cobalt-blue-vs-signal-blue/",
  "apiUrl": "https://www.colorsencyclopedia.com/api/compare/cobalt-blue-vs-signal-blue.json"
}