Range of measured values (smallest up to largest measurable value) that a photometer can cover. In most cases it is divided into measuring ranges.

In addition to the absorption of radiation when traversing an optical medium, such as glass, scatter (scattered light) can also cause an intensity reduction of the transmitted radiation.

In an optically homogeneous medium, the light progresses in a straight line. Any change of the optical properties by an obstacle will deflect the ray of light from its path. This physical process is called scattering of light by particles. Light scattering is the cause for turbidity.

In an optically homogeneous medium, the light progresses in a straight line. Any change of the optical properties by an obstacle will deflect the ray of light from its path. This physical process is called scattering of light by particles. Light scattering is the cause for turbidity.

Usually, these are cylindrical cells that have to meet high requirements as regards the existence of scratches, bubbles, and striae.

Usually, these are cylindrical cells that have to meet high requirements as regards the existence of scratches, bubbles, and striae.

Either a rectangular cell with an inside width of 2 to 5 mm or a cylindrical cell with a diameter of 5 to 8 mm.

Photometric concept in which only one light source and only one detector is used ( dual-beam method, photometer).

mainly is the designation for the permanent or sometimes also the reversible discolouration of certain glasses under the influence of radiation with a high UV percentage. This discolouration is combined with a reduction of the transmission in the transmission range.

mainly is the designation for the permanent or sometimes also the reversible discolouration of certain glasses under the influence of radiation with a high UV percentage. This discolouration is combined with a reduction of the transmission in the transmission range.

The spectral reflectance is the ratio of the reflected radiant flux to the incident radiant flux at a certain wavelength.

On request, cells can be put together in a set in which all cells, measured while empty, show the same transmittance value measured at a certain ? wavelength. Because of the validity of Lambert- Beer's law, the light paths of sets of cells with small light paths (below 1 mm) should be as similar as possible.

Distribution of the intensity of electromagnetic radiation as a function of wavelength. The interesting range for industrial photometry comprises the light waves, i.e. the visible, the ultraviolet, and the infrared light. Spectra produced by prisms or gratings make the spectral colours of the used light visible, starting from shortwave violet and on through blue, green, yellow and orange to long-wave red.

is the light in a photometer striking the receiver and producing a measuring signal without traversing the sample. Sometimes, a distinction is made between stray light which e.g. traversed the thick lateral walls of a semi-micro cell and extraneous light which originates from an external light source and often reaches the receiver by means of reflection at the walls. Both terms are also often summarised under the designation scattered light.

is the light in a photometer striking the receiver and producing a measuring signal without traversing the sample. Sometimes, a distinction is made between stray light which e.g. traversed the thick lateral walls of a semi-micro cell and extraneous light which originates from an external light source and often reaches the receiver by means of reflection at the walls. Both terms are also often summarised under the designation scattered light.

are in most cases threadlike defects in the glass that are apparent because of their different refractive index.

is a synthetic quartz glass manufactured by Heraeus Quarzglas GmbH.

Scratches and holes as well as nonpolished spots on the glass surface.