Hello, occasionally I come across Rodagon enlarger lenses which have some kind of strange green/purple/blueish color shiftings around the edge of especially the front cell. The area has varied from only a small area lika a halfcircle of 1.5mm in diameter to a 3mm wide area stretching several centimeters around the edges of the glass.
I have tried to stay away from these but since I have only seen it on Rodagons I am wondering if this is bad or not. People tell me they perform well despite this shifting color.
Any ideas as to what it might be and have you seen this on other brands?