Egg packages made from wood pulp and/or waste paper pulp have a white or a more or less grayish ground colour. This grayish colour shade depends among others upon the proportion of waste paper used, as well as upon the degree to which this waste paper was printed. Removal of this grayish shade, or brightneing, can be achieved by subjecting the waste paper to a de-inking process, by which a considerable part of the printing ink is removed.
In order to provide coloured egg packages, a chemical dye is added to the white or gray pulp, before egg packages with a corresponding colour are made of said pulp. This procedure has several appreciable disadvantages. For each single colour it is necessary to produce a specially coloured pulp. The egg packages are manufactured in a plant by means of suction moulds, mounted on a suction wheel, and it is necessary that suction moulds for a large number of different type of egg packages must always be at hand. When changing from one colour to another, or when changing from one package type to another, a change-over time for the plant of one hour or more may be necessary. During this time, nothing can be produced in the plant. Another disadvantage is that when colouring the pulp, an additional 99% water must be coloured, which means a very high consumption of dye. For this reason, a considerable amount of coloured water is produced, which is difficult to clarify. Large clarifying reserviors are needed for this purpose. The waste water of certain colour coming from the production process can only be re-used for new production of a pulp having the same colour. Furthermore is it difficult to adjust the colour shade when using the conventional method of manufacture, because it must be considered on a wet product. This insufficient control possibility leads to scrapping of approximately 10% of the egg packages. Furthermore, the control of the colouring is extremely difficult as the content of dye in the pulp only amounts to approximately 0.003% for obtaining the desired colour shade. In addition to this, the colour of the pulp will change uncontrollably according to the condition of the waste paper employed, as well as to the proportion of waste paper in the pulp, which is responsible for the various shades of gray to be found in the pulp. Another disadvantage is that once a coloured pulp has been introduced, it must be used up the same day. Because the dye also bonded in the pulp in the finished egg packages, the colour will lose some of its brilliance and soon fade. Nor should it be overlooked that the dye will be in contact with the packed eggs. All these problems have been greatly aggravated with the increasing number of package types and the increasing variety of desired colours. Nevertheless, for lack of alternative solutions, the same manufacturing methods have been used and are still used worldwide today.