Hello SSG Members using this site. This post is in part an attempt to start a discussion on this forum. Bear with me as I try to figure out how to go about posting a photo and comments. I recently shared this photo of my Provisional ‘Colour Variations’ with another student of Sudan Philately and he questioned the legitimacy of the ‘blue-green’ colour shade of the 2 mil value, pointing to the usual suggestion that they were ‘colour changlings’. I remain skeptical of this explanation as many of these stamps appear to be in excellent mint condition. I am open to other views and ready to acknowledge my mistake.