Which value in the mixture field of the Nagel Anomaloscope corresponds to pure 670 nm?

In the context of the Nagel Anomaloscope, the mixture field is used to create a specific color match between a test light and a reference light. The question asks about the value in this field that corresponds to a pure 670 nm wavelength.

The scale on the mixture field ranges from values that represent pure colors (like pure red or green) to mixtures of these colors. For the specific case of 670 nm, which is a wavelength in the red part of the spectrum, the corresponding value in the mixture field is often established through clinical tests and is generally agreed upon in literature studied in visual perception.

When interpreting the values, a value of 73 in the mixture field correctly indicates that this setting achieves a mix that aligns with the perception of pure red light at 670 nm, as the calibration of the device is specifically set to reflect these known standards. Therefore, selecting 73 for pure 670 nm indicates an understanding of spectral wavelengths and how they are quantified within the tools of color vision testing.