Every Henry Dean object is created out of mouthblown and handmade glass. The use of a wooden mould is a very primitive technique to create glass objects and has to be performed by the skilled hands of real artisans. Each time this mould is used, it burns out a little bit, thus giving each object its unique, handmade character.
Applying color to glass and experimenting with different techniques separately or combined to achieve this is one of Henry Dean's main fascinations right now. You can for example apply a double layer of color in a small oven specially made for that object. Another example is pulverizing color and applying it onto a clear glass mass.
The small imperfections and bulbs you may encounter in a glass or vase are a result of the artisans working method and are a part of every object's character.