There are three elementary requirements an invention has to meet in order to qualify for a patent. These are novelty, inventive step and industrial applicability. Although novelty is a fairly abstract concept, in practice it can be described in very concrete terms.
An invention is generally a solution to a certain technical problem for which a patent application can be filed. The novelty requirement and the conditions to be met in order to comply with this are the same for all patent granting bodies. However, the moment at which the novelty is assessed differs quite considerably per body. In contrast to the Netherlands Patent Office, the European Patent Office (EPO), for example, will assess and determine prior to granting whether an invention is novel, whereas the former will grant a patent and then only assess a product's novelty when a conflict about the patent arises.
Not yet public
Novelty means that the invention has never been made public which, of course, means that the invention must not have been published on a website, in a brochure or some other medium. This rule stretches pretty far, as it also includes publication in a simple local paper, a demonstration at a trade fair or a PowerPoint presentation shown to members of the general public anywhere in the world. It means that if an invention has seen the light of day at any point in time, it will no longer be possible to have it protected by a patent. The United States is the only exception because you can still get a patent there during a period of grace after publication.
Not spectacular or revolutionary
An invention most certainly does not need to be spectacular or revolutionary to meet the novelty requirement. An invention can be novel and patentable as long as it adds or improves something that already exists. Patents are still being granted nowadays, for example, on minimal modifications or improvements to the paperclip which could, for example, involve aspects of the design or strength.
Anyone who is considering applying for a patent, should study the literature on the relevant subject beforehand to find out whether the invention is truly novel. A patent attorney can help with this thanks to the easy access to patent publications across the globe and the insight he or she has into these.
A patent attorney can also advise on the patentability of an invention. Just suppose that elements A, B and C of an invention are already known. The addition of an unknown D element to that invention can then still ensure that it is regarded as novel and therefore patentable. One disadvantage of this approach is that any additions to an invention narrow down its protection and therefore make it less valuable.