Due to an impending extended shutdown (6 or more hours) the bath here in the FC furnace has been drained down to its lowest level. Although the remaining bath cannot be seen behind the forward ridge, the light from the remaining molten material is illuminating the lower portion of the back wall. The temperature inside is still around 2000 degrees and therefore, to compensate for the high dynamic range of the image (a measure of the range between light and shadow), and bring out depth and detail, a polarizer lens and a magenta filter were used on the camera. See the FC at operating bath level, image 151, without filters applied.