glass, are not negatively impacted by light levels, but “it is rarely necessary to exceed 300 lux.” Ultraviolet UV is a form of electromagnetic radiation with higher energy than visible light. It does not contribute to the accurate viewing of collections and is ideally completely eliminated; otherwise materials may be weakened in any number of ways ranging from yellowing to disintegration. Organic materials, especially textiles and paper, are particularly vulnerable to UV-caused decay. Direct sunlight holds the most potential for UV damage, but certain types of artificial light bulbs may also produce these harmful rays. Various types of filters have been developed to combat UV interaction with artifacts on display, and many of them can be used in conjunction with each other to reach the optimal setting for a particular collection. Among the first employed were heavy drapes; a simple solution to apply only if an institution can provide employees to open and close the drapes at the appropriate times based on viewer access. Many filtration devices rely on materials that absorb the UV, such as acrylic films or painted wash walls, but in doing this the materials themselves decay and the filters must be replaced. A better solution is interference filters, which can be customized for the setting of intended use to reflect light at such an angle that it cancels out harmful incoming wavelengths. If an interference filter is selected as the appropriate form of filtration, UV is eliminated completely and efficiently. Contamination with pollutants and dust Contaminants in a collection can pose a threat not only to the objects within the collection, but also to those individuals that come in contact with them. It is therefore necessary to ensure that all objects brought into a collection are carefully documented and researched to prevent accidental contaminations, and to create storage conditions, such as those mentioned above, to mitigate the potential for future contaminate development. Potential contaminants can take the form of gases, liquids, or solids and may therefore pollute objects, and the individuals caring for them, through airborne delivery or physical contact. Collections affected by contaminants will show signs of disintegration, discoloration, or corrosion, with porous materials being the most susceptible. Gaseous pollutants Pollutants in the storage environment atmosphere can also cause damage to material surfaces. In particular silver objects are vulnerable to sulphurous gasses which cause them to tarnish, and lead and pewter objects will corrode when