Hello Henk-Jan, The R Wpg R's first title was the triangular "black devil" title. With the shape and the devil inside, it was difficult and therefore expensive to make. It was authorized to be replaced by the white (oyster coloured) embroidered title on black. The black was reflective of their rifles' heritage. However, some information suggests that the colour was supposed to be "rifle green" which in the R Wpg R case was a very very dark green. It appears the manufacturers couldn't get a dark dark green and substituted a black. After the war when the unit returned to Canada, they switched to the dark green as it was supposed to be the correct colour for regimental titles. (One can argue that the dark green used in the late 40's and 50's was not a true rifle green as it was not dark enough.)
Canadian army printed titles were discontinued at the end of the war. The only maker was a British company called Calico Printers, at their Broad Oaks Print Works. The company silk screened the designs on a cotton material. The cotton material was made in different finishes, and one was a cotton drill. Calico tried to print dark rifle green titles on this material, but the product wasn't acceptable. It "grayed" out on the cotton drill. So, CMHQ authorized Calico to change to a medium green ink on the cotton drill. These titles were not acceptable. Calico was asked to get the proper type made and they switched to a satin cotton drill which took the ink dyes much better. They are the white on black issue.