Through an extensive coating stack design and testing program, Baader has partnered with the world's leading thin film coating company to produce transmission curves that border on the ideal. Their ultra steep cutoffs and high transmission (>95%) allowed Baader to do something to a degree no other RGB filter set can manage - they are able to effectively separate the important H-Beta and O-III lines. The Baader Blue filter passes virtually all of the H-Beta and O-III lines, while the Green filter is able to capture all of the O-III line, without encroaching into the H-Beta line. None of the light is wasted by either filter. In this way, O-III is represented as it should be, a teal (blue-green) color, and H-Beta is captured solely in the blue. Never before has this degree of separation been achieved, and with such high transmission of both lines.
In addition, the Green and Red filter passbands nearly touch, leaving only a sharp notch to block out the primary Mercury/Sodium light pollution line at 580nm. The high transmission everywhere else delivers the shortest combined exposures possible with every detector.
In addition to their special transmission properties, the Baader coatings were developed from the outset with another key goal in mind - eliminate the annoying reflections present in other astro-filters. To achieve this freedom from reflections required careful balancing of the coating stacks and further extensive testing.