Studying Loetz Ground Colors!

I have always loved studying Loetz ground colors. Being able to document various ground colors as well as understanding the variation of colors that appear once iridescence is applied has always been fascinating to me. For example, I have a Loetz "Candia Silberiris" inkwell, PN 85/3930/I. Depending on the light, this inkwell can appear either blue or candia. The fun thing is that I can also play with a "lid sample" that matches this color both in iridescence as well as ground color. This lid sample allows me to accurately see both the ground color as well as the iridescent layer in various lighting.