There exist three other forms:
1.sometimes you can find the Lagorio-tableau – 16 colorstripes are combined with 13-part grayscales. The tableau is around 24x30cm and was made in ?Czecheslowakia?Poland?. Named VUZORT. The U has a accent. I have heard, that other forms had exist.
2.The Schott variable Interferenzfilter from around 360 to 800nm. It is ca 27 mm x 190 mm, my is combined with a parallel graystep made by grainless bw film. Ideal for 35mm films to control.
3.In older times scientist had have a pocket-spectrometer. This is today in the program of scientific tools, but you will find often on auctions for history of technology and science. A Zeiss Jena with scale 400-700nm is combined with a simple only mechanical construction from ICA, Dresden (famous camera-company) for 6.5 x 9 cm plates, where a 8mm slit will exposed in 7 following positions. In the plate-cassettes it is simple to mount 2 parallel 35mm stripes.