This post is another article I made specifically to help me out more than to share information with you. I have a hard time remembering what colors of hot metal means, so I did some research and found several charts to explain. This one was the best for my purposes and came from stormthecastle.com, this is a very cool website and they have a lot of good information.
The problem with Blacksmithing Color Chart of Steel like this is that they are slightly different for the different types of irons and iron alloys. Additionally (and more problematically) the colors are subjective and will be seen by the same person differently depending on conditions at the worksite (more or less light, overcast or clear conditions)
Additionally different types of metal act differently at the same heat color. Some have a short working temperature, which means that they only should be worked at medium to bright yellow. If it gets to orange yellow quit and take another heat. This is something you will have to either learn on your own or seek the advice of others that have worked this type steel.
Your eyes see colors differently then how others see and label the same color due to age, glasses, and life experiences. You are building YOUR heat standard for YOUR forge under YOUR smithy conditions.
If you really want/need to know what temperature a specific color represents, or what temperature the steel has been heated to, purchase a temperature measuring device called a pyrometer.
I would also suggest that you buy special wax pencils that can be applied to the steel that will melt at a specific temperature. (the wax is also useful when annealing brass for reloading purposes).
So realizing that this chart is just a guide and it does not supplant personal experience at your forge, under your conditions it is quite useful beginners like me.