Colour Models
Colour Models is a free interactive simulation from StudyFi Lab. It runs right in your browser, with no sign-up and nothing to install.
Mix light and inks: RGB, CMYK and HSV
Experiments
RGB light (additive)
Three coloured spotlights – red, green and blue – shine on a black wall. Where the beams overlap, their light adds up: red + green = yellow, green + blue = cyan, red + blue = magenta, and all three at full strength give white. Every pixel of a screen mixes its colour the same way from three channels of 0–255, so it can show 256³ ≈ 16.7 million colours.
Try this: Switch blue off and set red and green to the same value – you get yellow. Then slowly lower green and watch the yellow turn orange.
CMYK inks (subtractive)
A printer starts with white paper and adds inks that absorb light: cyan absorbs red, magenta absorbs green and yellow absorbs blue. Every overlap removes more light, so cyan + yellow = green and all three together make a dark brownish black. For a true black and crisp text a separate black ink K is added: R = 255 · (1 − C) · (1 − K).
Try this: Set cyan and magenta to 100 % and yellow to 0 – you get blue. Then add K and watch the whole colour darken.
HSV: hue, saturation, value
HSV describes a colour the way we talk about it. Hue H is an angle on the colour wheel (0° red, 120° green, 240° blue), saturation S says how vivid the colour is (0 % = grey) and value V how bright it is (0 % = black). Drawing apps use it because “a bit darker” simply means moving V.
Try this: Keep V at 100 % and lower S – the colour fades to white. Then set S to 0 % – now V only gives you shades of grey.
Guess the colour
Mix the target colour in any model you like. The match is judged by ΔE₀₀ (CIEDE2000), a colour difference built so that equal numbers look equally different to the eye: below 1 almost nobody sees a difference, around 3 it shows side by side. After each check you get a hint about what to change first.
Try this: Try the same target once with RGB and once with HSV – which model gets you there in fewer moves?
Frequently asked questions
What is Colour Models?
Colour Models is a free interactive simulation from StudyFi Lab. It runs right in your browser, with no sign-up and nothing to install. Mix light and inks: RGB, CMYK and HSV
Is Colour Models free?
Yes. Colour Models is completely free. It works in the browser on computers, tablets and phones, and you do not need an account.
What can I explore in Colour Models?
RGB light (additive), CMYK inks (subtractive), HSV: hue, saturation, value, Guess the colour.
What does the “RGB light (additive)” experiment show?
Three coloured spotlights – red, green and blue – shine on a black wall. Where the beams overlap, their light adds up: red + green = yellow, green + blue = cyan, red + blue = magenta, and all three at full strength give white. Every pixel of a screen mixes its colour the same way from three channels of 0–255, so it can show 256³ ≈ 16.7 million colours.
What does the “CMYK inks (subtractive)” experiment show?
A printer starts with white paper and adds inks that absorb light: cyan absorbs red, magenta absorbs green and yellow absorbs blue. Every overlap removes more light, so cyan + yellow = green and all three together make a dark brownish black. For a true black and crisp text a separate black ink K is added: R = 255 · (1 − C) · (1 − K).
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