With good body health, urine usually appears as some form of yellow. Things that effect the colour include consumption of vitamins, food or medication, as well as your body's hydration levels. As our body uses its filtration system for liquids, many processes take place that cause the yellowing of urine.
Haemoglobin is a protein responsible for carrying oxygen within your red blood cells. As this protein breaks down in your system, it produces a pigment called urochrome. This gives urine its yellow hue.
A vividly bright yellow urine, or a more golden yellow urine, likely reflects the intake of the vitamin B family, as well as carotene. As your body breaks down the vitamins in your system, the excess filters out through your kidneys and then to your urine.
If your body is fully hydrated, the water dilutes the urochrome yellow, making your urine appear moderately clear. When you are dehydrated, the dilution does not occur, resulting in a much darker colour yellow to your urine.
While urine is normally some variation of yellow, it may appear as some other colour, due to consumption of a food, food dye, or medication. Colours can vary from orange to dark brown to green and even red/pink. These symptoms are temporary and can usually be traced back to the food or medication that you consumed. Prolonged colour changes in urine colour may signal much more serious symptom, prompting you to seek out medical assistance.