Dr. Hanneman's "Poor man's Chelsea Filter" 2000s

The “Poor Man’s Chelsea Filter” is part of a family of coloured gemological filters produced by Dr. W. William (“Bill”) Hanneman. He developed a range of inexpensive colour filters designed to help hobbyists, students, and amateur gemologists perform simple visual tests on gemstones without needing expensive instruments. These filters were intended to mimic or expand on the principles of the Chelsea filter (originally invented in 1934 by Anderson & Payne) but with a broader and more accessible design and price point. 

In listings of Hanneman filter sets — such as those marketed under names like “The Works,” “Bead Buyer’s & Parcel Picker’s Filter Sets,” or the PMCF itself — the Poor Man’s Chelsea Filter is specifically included as one element in this line of affordable gem filters. 

According to product descriptions, the PMCF was developed to operate on similar optical principles to a Chelsea filter, though with different transmission bands that allow broader wavelengths (for example, a transmission centre around 525 nm rather than the strict yellow-green/deep red bands of the classic Chelsea filter). This makes its reactions somewhat comparable but not identical to those of a true Chelsea filter. 

The inclusion of the filter in modern filter sets (e.g., models listed from the 2000s like “PMCF Set – Model 2005” in The Works filter set) strongly suggests that by the early 2000s the PMCF was already in production and being marketed as part of Hanneman’s affordable gem filter line. 

This is a museum archives and no unit is available for sale at this moment.