Photoshop's RGB to HSB calculation

[scotwllm]

When I type RGB values or a hex code into Photoshop's color picker, it automatically calculates HSB values. What are the formulas used to calculate the H, S, and B values presented in the color picker tool?

Scott

[Kevin Stohlmeyer]

See this existing thread regarding RGB/HSB calculations:

https://community.adobe.com/t5/photoshop-ecosystem-discussions/calculate-hue-from-rgb/td-p/12603371

[scotwllm · Accepted solution]

H = IF(180/PI()*ATAN2(2*R-G-B,SQRT(3)*(G-B))<0,180/PI()*ATAN2(2*R-G-B,SQRT(3)*(G-B))+360,180/PI()*ATAN2(2*R-G-B,SQRT(3)*(G-B)))

S=(Max(R,G,B)-Min(R,G,B))/Max(R,G,B)

B=Max(R,G,B)/255