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Base color in hsl(h,s%,l%) format: *

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Type a value, then press compute.

1️⃣ Shift base color by this percentage:
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2️⃣ or a target hue in hsl(h,s%,l%) format:
└

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Modulate is an ImageMagick command that can shift the hue of a given color by the provided percentage. More info here. To understand how 'hue shift' works, imagine a colorwheel where:

A = original color, used as a base for the computations
B = new color, as shifted from A by 𝒏 percent

ImageMagick takes the base color and assigns it a value of 100%. It then works out the % values of the other colors :

• The opposite color on the wheel is assigned 0%.
• Starting from this 0% value, it moves clockwise along the colorwheel perimeter adding 1% for each color until it reaches 200%.
• By this point, it has already circled back to 0%. Logically, this means that colors bearing the 0% and 200% values are the same.

Now, when a user provides a percentage, ImageMagick simply returns the color associated with that % value.