Nail the exact color yellow in your design by using the code from any one of these systems for color identification.
|RGB||r: 255, g: 255, b: 0|
|HSL||h: 60°, s: 100%, l: 50%|
|HSV||h: 60°, s: 100%, v: 100%|
|CMYK||c: 0%, m: 0%, y: 100%, k: 0%|
If you're identifying color for pretty much anything digital, you're working in an RGB colorspace. If the project you're working on requires percentage representation, yellow is made of 100% red, 100% green, and 0% blue.
If you're identifying color for a print project, you're most likely using a CMYK colorspace—the percentages are 0% cyan, 0% magenta, 100% yellow, 0% black.