Knut Bergkvist developed the graal technique in 1916 at Orrefors. He was inspired by the French art nouveau glass of Daum and Gallé of that time. The name graal was inspired by the saga of the Holy Graal which contains the blood of Christ. The first graal pieces were ruby red and had the aspect of a red liquid freely flowing in the vase. Hence, the analogy to the blood of Christ and the name Graal.
In the graal technique a colored layer of glass is encased by a transparent layer of glass. The glass is then allowed to cool down and when it is cold the design is applied by engraving or etching. The obtained “stock” of “blank” piece of glass is then carefully reheated and blown into its final shape. During this process the sharp edges of the design become smooth and the motive becomes more soft and blurred, giving it its typical Graal aspect. The Graal technique was a huge commercial success for Orrefors and was the beginning of what can is nowadays seen as the swedish art glass movevement.
The Graal technique was widely used by Öhrström (Ohrstrom), Hald and Gate. Although lesser known, Ingeborg Lundin also made quite a few pieces using the Graal technique while at Orrefors.
You can find all the date codes and/or serial numbers related to Orrefors Graal on the following link: Dating Orrefors Graal