With some varieties it is easy to get the new color in one generation. Type can also be done in one or two generations depending on how close the breeds already are.
Lets use crele for an example for color. For the breed we can use welsummers. You would first start with a barred rock cock and welsummer hens. You would cross them and get crele colored birds and depending on the type of the birds you start with the type would be set too. So for that example you could get color and type in the first cross.
Other things can be really easy like getting a new color in a breed by using two seperate colors in that breed. Like blue cuckoo in cochins. You would cross a barred/cuckoo cock to splash hens and get all blue cuckoo chicks and you wouldnt have to worry about the type because you didnt cross breed, just cross color.
Lets use crele for an example for color. For the breed we can use welsummers. You would first start with a barred rock cock and welsummer hens. You would cross them and get crele colored birds and depending on the type of the birds you start with the type would be set too. So for that example you could get color and type in the first cross.
Other things can be really easy like getting a new color in a breed by using two seperate colors in that breed. Like blue cuckoo in cochins. You would cross a barred/cuckoo cock to splash hens and get all blue cuckoo chicks and you wouldnt have to worry about the type because you didnt cross breed, just cross color.