Recognised as Colour

#FF3F17

#FF3F17
Red
Dark
Nearest: Orange red

#FF3F17 is a red with RGB values 255, 63, 23 and HSL 10°, 100%, 55%. It is a dark colour, so black text on it reaches 6:1 contrast (AA for normal text). The nearest named colour is Orange red.

Colour values

#FF3F17#FF3F17

HEX#FF3F17

RGBrgb(255, 63, 23)

RGB (0–1)1, 0.2471, 0.0902

RGB percentages100%, 24.7%, 9%

HSLhsl(10.3, 100%, 54.5%)

HSV / HSBhsv(10.3, 91%, 100%)

CMYK0%, 75.3%, 91%, 0%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer16,727,831

CSS custom property--colour: #FF3F17;

Brightness & contrast

Relative luminance0.24877WCAG 2.x, 0 is black and 1 is white

Perceived brightness147.8 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundBlackcontrast 5.98:1

Contrast with white3.51:1WCAG normal text: Fail

Contrast with black5.98:1WCAG normal text: AA

Greyscale equivalent#656565

Inverted#00C0E8

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#7C6E09no red cones; affects about 1% of men; ΔE 76.4 from the original

Deuteranopia#AB9800no green cones; the most common form, about 1% of men; ΔE 76.2 from the original

Tritanopia#FF003Ano blue cones; rare, and affects men and women equally; ΔE 22.4 from the original

Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning

Contrast with white, large text3.51:1WCAG large text: AA

Contrast with black, large text5.98:1WCAG large text: AAA

Named colours

Orange red · ΔE 6.2 Red · ΔE 11.6 Tomato · ΔE 21.3 Coral · ΔE 30.9 Crimson · ΔE 31.2 Chocolate · ΔE 33.5

Nearest named CSS colourOrange red (#FF4500)ΔE 6.17, clearly different but related

Hue familyred

CSS keyword usableNo exact keyword

Colour harmonies

base +30°+90°+120°+180°+210°+240°+270°+330°

Complementary#17D7FF

Analogous#FF1763, #FFB317

Triadic#17FF3F, #3F17FF

Split complementary#17FFB3, #1763FF

Tetradic#63FF17, #17D7FF, #B317FF

Tints, shades & saturation

+40%+30%+20%+10%base -10%-20%-30%-40%

Lighter +40%#FFE8E3

Lighter +30%#FFBEB0

Lighter +20%#FF937D

Lighter +10%#FF694A

Darker −10%#E32700

Darker −20%#B01E00

Darker −30%#7D1600

Darker −40%#4A0D00

More saturated +25%#FF3F17

Less saturated −25%#E25234

Channel breakdown

R255

G63

B23

Red255 (100%)

Green63 (24.7%)

Blue23 (9%)

Hue10.34°

Saturation (HSL)100%

Lightness54.51%

Dominant channelRed

Hex per channelR FF · G 3F · B 17

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Harmonies

Lighter and darker

Similar named colours

Also reads as

FF3F17 (chemical formula)

Formula
398.958 g/mol
21 atoms

FF3F17 has a molar mass of 398.958 g/mol, made up of 21 atoms across 1 element: 21 × F.

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Molar mass

Molar mass398.958 g/mol

Total atoms per molecule21

Distinct elements1

Mass of one molecule6.6248535 × 10^-22 g

Molecules per gram1.5094674 × 10^21

Name

NameNot in the name tablea name cannot be worked out from a formula alone: isomers share formulas, and naming depends on bonding the formula does not show

Composition by mass

F100%

Fluorine (F × 21)398.958 g/mol, 100%

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Elements in this formula

Fluorine

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