Graeme Gill schrieb:
Klaus Karcher wrote:There is a "LonGTrack" (54cm, approx. 100 EUR) from basICColor". One can also try to use a ruler or bar of suitable thickness. But I guess all that is not really conducive to measurement repeatability.OK, I'll have to think about how to handle that.
I jut saw that there are even 72cm "LonGTracks" <http://www.colorklinik.de/product_info.php?manufacturers_id=11&products_id=351>