A process for determining animal cell confluence comprising: arranging a biological sample container in which animal cells are being cultured in an object position of an imaging station; illuminating the object position with an optical source from below; collecting light from the optical source that has been scattered at the object position to form an image of the biological sample container arranged in the object position with a detector; wherein, in said illuminating step, the object position is illuminated at an oblique angle; wherein said oblique angle at which the optical source illuminates the object position is between 10 to 50 degrees to the horizontal; wherein, in said collecting step, the image is taken in a dark field configuration where light from the optical source, if not scattered, does not contribute to the image; processing the image to determine the degree of confluence of the animal cells in the biological sample container, wherein the degree of confluence is the degree to which the animal cells have grown to fill the area of the biological sample container that is available for animal cell growth, and wherein said degree of confluence is determined: by an automated cell count which is translated into an area by multiplication of the cell count by an area representing an average area for the cell type being cultured, or by processing the image to: establish cell boundaries, compute the area of each cell from the cell boundary, and sum the cell areas. arranging a biological sample container in which animal cells are being cultured in an object position of an imaging station; illuminating the object position with an optical source from below; collecting light from the optical source that has been scattered at the object position to form an image of the biological sample container arranged in the object position with a detector; wherein, in said illuminating step, the object position is illuminated at an oblique angle; wherein said oblique angle at which the optical source illuminates the object position is between 10 to 50 degrees to the horizontal; wherein, in said collecting step, the image is taken in a dark field configuration where light from the optical source, if not scattered, does not contribute to the image; processing the image to determine the degree of confluence of the animal cells in the biological sample container, wherein the degree of confluence is the degree to which the animal cells have grown to fill the area of the biological sample container that is available for animal cell growth, and wherein said degree of confluence is determined: by an automated cell count which is translated into an area by multiplication of the cell count by an area representing an average area for the cell type being cultured, or by processing the image to: establish cell boundaries, compute the area of each cell from the cell boundary, and sum the cell areas. by an automated cell count which is translated into an area by multiplication of the cell count by an area representing an average area for the cell type being cultured, or by processing the image to: establish cell boundaries, compute the area of each cell from the cell boundary, and sum the cell areas.