In the European Union especially, there is a demand for cheaper alternatives to white golds than the palladium whites which are 'nickel-free'. Many new alloys are coming to market, most of which rely on manganese additions as the main whitener. Some are palladium-free and others are low palladium alloys. Chromium and iron are also be used as whiteners. They tend to be hard and more difficult to process. Many of these alloys are not a good white colour, requiring rhodium plating, and many suffer cracking problems and tarnishing.
We recently tried to anneal a batch of white gold from Italy. It was so unmalliable we had to contact the manufacturer, and whilst the solution was simple, a high street working jeweller would find the new metals difficult, if not impossible to process.

Platinum, chromium, cobalt, zinc, tin and silver are all used as whiteners. Silver has excellent working properties but is poor as a whitener. Copper is also added to improve the ductility of most white alloys.

Rhodium Plating
It is important to remember that even the best white gold alloy is actually grey, as is platinum. The white finish you are accustomed to is a rhodium plating, and whatever you are told, white golds are only available in caratages up to 21 carat. It is not possible to have a 22 ct white gold!