Palettes / Colors / #283F8B

#283F8B — Blue

#283F8B is a blue color we call Blue, closest to the named color DarkSlateBlue (#483D8B). It belongs to the blue family.

Color name

Closest CSS keyword: darkslateblue (#483D8B) — not an exact match. CSS darkslateblue gives you #483D8B, a different color; use #283F8B when you need this exact shade.

Sources: common names follow widely used color-name references; CSS keywords and their hex values follow the CSS Color specification.

#283F8B is a cool blue color associated with trust, calm and professionalism. It sits comfortably in the middle: usable for large areas in soft schemes, or as a supporting color beside something stronger.

Its strongest partner is its complement #8A7328; it also sits naturally between #28708A and #42288A. In the palettes below you can see it working alongside real color combinations from our collection.

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Color values

RGB & CMYK percentages

Red 16% · Green 25% · Blue 55%

Cyan 71% · Magenta 55% · Yellow 0% · Key 45%

CMYK values are unprofiled approximations for screen reference — not a print-proofing guarantee.

Previews

CSS code for #283F8B

.text { color: #283F8B; }
.background { background-color: #283F8B; }
.border { border: 3px solid #283F8B; }
.text-rgb { color: rgb(40, 63, 139); }
.text-hsl { color: hsl(226, 55%, 35%); }
.text-shadow-hex { text-shadow: 4px 4px 2px #283F8B; }
.text-shadow-rgba { text-shadow: 4px 4px 2px rgba(40, 63, 139, 0.8); }
.box-shadow-hex { box-shadow: 1px 1px 3px 2px #283F8B; }
.box-shadow-rgba { box-shadow: 1px 1px 3px 2px rgba(40, 63, 139, 0.8); }

HTML: <p style="color:#283F8B">Text here</p> · <div style="background-color:#283F8B">Div content here</div>

Shades of #283F8B

Tints of #283F8B

Tones of #283F8B

Color harmonies

Complementary — #8A7328:

Analogous:

Triadic:

Contrast & accessibility

Best text color on #283F8B: #FFFFFF.

Semi-transparent (opacity) text on #283F8B

Text set with opacity blends into the background, so its real contrast is lower than the solid ratios above. Choose a text color and an opacity to see the blended color and its true ratio:

How #283F8B looks with color blindness

Simulated with standard Machado color-vision-deficiency matrices — useful when this color carries meaning in charts, maps or interfaces:

Closest design-system colors

The nearest matches in the Tailwind CSS, Material Design and Bootstrap palettes — handy when you need a framework class instead of a raw hex:

Palettes with a similar color

These palettes use a close neighbour of #283F8B rather than the exact color:

Similar colors

The closest colors that actually appear in our palette collection — click any to open its page:

Browse neighbouring colors

← #283F8A  ·  #283F8C →

Frequently asked questions

What color is #283F8B?

#283F8B is Blue, a blue color (RGB 40, 63, 139). Its closest standard named color is DarkSlateBlue.

What is the RGB and HSL of #283F8B?

#283F8B is RGB 40, 63, 139 — HSL 226°, 55%, 35% — CMYK 71%, 55%, 0%, 45%.

What colors go with #283F8B?

Its complement is #8A7328; analogous partners are #28708A and #42288A. It also appears in 6+ palettes in our collection.

Can I use #283F8B for text?

White text on #283F8B has a contrast ratio of 9.66:1 (passes WCAG AA); black text gives 2.17:1.