The Difference Between Dex Gum And Pva Gum

I was just looking at some Centennial Canadian MNH postage dues and was looking at the difference between the 2nd and 3rd issue…1c, 4c, 8c, 10c and 12c….the sizes are the same,etc….however the 2nd issue has Dex Gum and the 3rd issue Pva Gum.

On reading an earlier post it suggested that Dex Gum was whiter( my interpretation), however I attach a photograph of two postage dues, the left hand one is a 1st issue 2c as it is slightly larger and states it is Dex Gum and the right hand one is a 4th issue 50c which states Pva gum.
The Dex Gum appears to be more yellowish than the Pva gum….is this a correct assumption

Any help?
Dex gum - gum used on back of Canadian stamps until 1971 when it was replaced by PVA gum.

Also
Dextrose and PVA
The Gum Types On The 1967-1973 Centennial Issue
http://canadianphilately.blogspot.c...tennial.html

Many thanks
, the blog was quite helpful.

Regards

Robert

In generak, but specifically for the Centennial issue, the Dextrose gum has a yellowish tint to it. It can also appear both smooth and streaky. The PVA gum, is generally colourless, and therefore appears white.

Cheers for response.