HueSatVal

See the colour decisions behind great paintings

A shadow isn't just a darker version of the lit colour. Painters shift its hue, mute it, and save saturation for where it counts. Those choices are hard to see and harder to check. HueSatVal separates any picture into value, hue and saturation, so you can see them, and measure them.

Try the example ↓
  1. 1Paste an artworkCopy any image (right-click → Copy image), then press Ctrl+V anywhere on this page. Or drop a file.
  2. 2Put the lens on one objectDrag the lens, drag its edges to resize. The panel describes what's inside it.
  3. 3Switch viewsKeys 1–0: value, hue, hue shift, warm/cool, edges, palette…
  4. 4Check your guessClick the lit side, then its shadow. See exactly how the hue, saturation and value changed.

What each view shows you

Each view hides everything except one property of colour, so you can see what the artist did with it. Click one to switch the lens above to it.

Is my image uploaded anywhere?

No. Everything happens inside this page, on your computer. The only thing the site counts is how many images were studied: a number, nothing about the image.

What's "value", and why L*?

Value is how light or dark a colour looks. Colour pickers show HSV "V", which says pure yellow and pure blue are equally bright. HueSatVal uses CIE L*, which matches what your eye sees.

Can I analyse a video or a page I'm scrolling?

Yes. Use Watch a window and pick the tab or window. The lens follows it live; Freeze keeps the current frame so you can pin samples.

How to use HueSatVal

Paste / drop / openLoad an artwork (Ctrl+V works anywhere on the page)
Drag inside the lensMove it
Drag an edge or corner, or scroll over the lensResize it
Drag outside the lensDraw a new lens
Click inside the lensPin a colour sample (up to 6); right-click removes the nearest
1–9, 0, -Switch view (- is “without hue shift”)
[ ]Fewer / more value steps or palette colours
M or the buttons on the imageCompare style: Lens (a window on one object), Slider (original | view, drag the divider or use ← →), Full (the whole picture)
Hold Space or “Hold for original”Peek at the original
S / C / DelSave a study / copy the lens image / clear samples
TabHide or show the panel
Watch a windowAnalyse a video or a page you scroll, live. Your browser asks which window to share; nothing leaves your computer.

Pin a lit area first, then its shadow: the panel tells you exactly how the artist shifted hue, saturation and value. The light/shadow, ramp and hue-shift analyses work best with the lens on one object.