User Rating 0.0
Total Usage 0 times
Category CSS Tools
Closest Match
...
Contrast (WCAG)
White Text
Black Text
Color Harmonies
Complementary
Triadic
Analogous
Shades
Copied to clipboard!
Is this tool helpful?

Your feedback helps us improve.

About

Color precision is paramount in digital interface design and print production. The conversion between additive models (Light: RGB, HEX) and subtractive models (Ink: CMYK) involves complex mathematical approximations due to differing gamuts. This tool acts as a bridge, utilizing rigorous geometric algorithms to map coordinates from the HSVA space (Hue, Saturation, Value, Alpha) to all industry-standard formats instantly.

We specifically address common developer frustrations: lost alpha channels during conversion, rounding errors in CSS percentages, and the lack of visual accessibility feedback. By calculating the Relative Luminance (L) of the selected color in real-time, this application automatically suggests whether to use dark or light foreground text to satisfy WCAG 2.1 contrast ratios (AAA/AA standards), preventing common accessibility violations before they enter production code.

color picker css converter cmyk web design accessibility

Formulas

Color conversion logic relies on normalizing standard 0-255 RGB integers to a 0-1 continuous range. Below are the critical formulas used for translation and luminance validation.

RGB to CMYK (Key Black Extraction)

First, normalized RGB values (r', g', b') are used to find the Key (Black) component.

K = 1 max(r', g', b')

Then, calculate Cyan, Magenta, and Yellow, handling the singularity where K = 1.

C = (1 r' K)(1 K)

Relative Luminance (Accessibility)

Standard WCAG definition for perceivable brightness. Gamma correction is applied to RGB components first.

L = 0.2126 Rlin + 0.7152 Glin + 0.0722 Blin
{
Clin = CsRGB12.92 if CsRGB 0.04045Clin = CsRGB + 0.0551.0552.4 otherwise

Reference Data

CSS NameHEXRGB (r,g,b)HSL (h,s,l)
Crimson#DC143C220, 20, 60348, 83%, 47%
CornflowerBlue#6495ED100, 149, 237219, 79%, 66%
DarkOliveGreen#556B2F85, 107, 4782, 39%, 30%
GoldenRod#DAA520218, 165, 3243, 74%, 49%
LightSalmon#FFA07A255, 160, 12217, 100%, 74%
MidnightBlue#19197025, 25, 112240, 64%, 27%
SeaGreen#2E8B5746, 139, 87146, 50%, 36%
SlateGray#708090112, 128, 144210, 13%, 50%
Tomato#FF6347255, 99, 719, 100%, 64%
Rebeccapurple#663399102, 51, 153270, 50%, 40%
Teal#0080800, 128, 128180, 100%, 25%
Fuchsia#FF00FF255, 0, 255300, 100%, 50%
Lime#00FF000, 255, 0120, 100%, 50%
Maroon#800000128, 0, 00, 100%, 25%
Aquamarine#7FFFD4127, 255, 212160, 100%, 75%

Frequently Asked Questions

Screens use RGB (additive light) which has a wider gamut, capable of producing bright neons. CMYK is subtractive (ink reflection) and is physically limited by pigment capabilities. The tool simulates this restriction, so "out of gamut" warnings appear when you pick a color that physically cannot be printed without shifting.
Standard HEX uses 6 digits (#RRGGBB). Modern CSS supports 8-digit HEX (#RRGGBBAA) where the last two digits represent transparency (00=0% to FF=100%). This tool automatically toggles between 6 and 8 digit logic based on your Alpha slider adjustment.
The EyeDropper relies on the browser's native ColorSelection API. This captures the raw pixel data directly from your GPU buffer, bypassing color profiles in the CSS rendering layer. Note: This feature currently works on Chromium-based browsers (Chrome/Edge).
They are different geometrical representations of RGB. HSB (or HSV) uses "Value" (Brightness), modelling a cone where maximum value contains full colors. HSL uses "Lightness", modelling a bicone where maximum lightness is always pure white (regardless of saturation). Designers usually prefer HSB; CSS standardizes HSL.