I was just looking through the "Film Developing Cookbook" and saw a mention of the developer FX-2K. Comparing it to FX-2. I also checked the web and found---Originally formulated by Geoffrey W. Crawley. FX 2K, a variation, provides more flexibility with enhanced midtones. Has anyone used this? What exactly is meant by "more flexibility?" Thanks----JimJ(posted 8364 days ago)