What it is for
Pulling an exact colour out of an image you do not have the source for — a logo someone sent as a PNG, a screenshot of a competitor's interface, a photograph you are matching a background to.
The image is scaled to fit the panel, and clicks are mapped back to its real pixel grid, so the value you get is the pixel you pointed at rather than the one under the scaled cursor.
One pixel or a region
A single pixel is right for flat artwork and wrong for photographs, where neighbouring pixels can differ by a lot. If the answer is coming out noisy, you want the region average instead — that is what the palette extractor computes.
Colour profiles, briefly
Images can carry a profile saying how to interpret their numbers. The browser converts to the display profile, and this samples the result. For screen work that is exactly the number you want. For print, sample in software that respects the source profile — the values will legitimately differ.
Build variants in HSL
Once you have a brand colour, switch the reading to HSL and change only the lightness to derive hover, disabled and border shades. Nudging three hex components independently drifts the hue; changing one number does not.
Questions
Why does the colour differ from what I see in Photoshop?+
Colour profiles. A photograph tagged Adobe RGB or Display P3 is converted for the screen, and what you sample here is what the browser decoded — the value a web page will actually show. For print work, sample in the application that owns the profile.
Is it sampling one pixel or an average?+
One pixel, exactly under the cursor. That is the right behaviour for picking a brand colour out of a logo. On a photograph, single pixels vary a lot — use the [palette extractor](/t/palette-extractor) when you want the colour of a region rather than a point.
Why are HEX, RGB and HSL all shown?+
Because different places want different notations, and converting by hand is a pointless step. HSL is the one worth switching to when you need lighter and darker variants — adjust the L and the hue stays put.
Does it work on a screenshot?+
Yes, and that is the common case: sampling a colour from a screenshot of a site or an app whose CSS you cannot read.