Craft paper is produced on paper machines with moderate machine speeds. The raw material is normally softwood pulp from the Craft process. Maintaining a high effective sulfur ratio or sulfidity is important for the highest possible strength using the Craft process. The Craft process can use a wider range of fiber sources than most other pulping processes. All types of wood, including very resinous types like southern pine, and non-wood species like bamboo and kenaf can be used in the Craft process.