Siegessaule: The Berlin Victory Column.

Siegessaule in Infra Red.

 

This is a genuine image of the Siegessaule shot in the infra red part of the visible spectrum, at 950 NanoMetres.

 


Among foolish notions generated out of "photoshop" culture is that of after-shot  "digital infra red filters". You cannot obtain from a non-infra red image what actually would have been recorded in infra red by merely simulating the look of  such an image. That would be like saying that you can obtain an X-ray image by simulating digitally the look of such an image. It is fundamentally absurd: the computer has no access to the patterns of information specific to the wavelength of radiation being recorded.Hydrogen scatters strongly and therefore water-bearing features, cloud, foliage and people, show brightly as white in the image. A computer programme cannot determine from the information visible in an image what the composition of that imaged is. It follows that it cannot recreate such infra red images as might have been recorded from that subject.

 

 

This image was recorded in strong sunlight but required a long exposure, handheld. The  digital recording of the image is effected by removing the IR cut filter from in front of the camera CCD and substituting an IR pass filter at the front of the lens. All CCDs are vastly more sensitive to IR radiation than visible light. The IR cut filter is therefore necessary to prevent the recording of visible light from being drowned out. Removal of the filter admits this abundance of IR radiation but it in order to obtain an image from purely that light it is necessary to introduce the IR pass filter at the front of the lens. This blocks all visible light. It appears totally black to the unaided eye and cannot be seen throough. But it admits the IR radiation that forms the image. However, the overall result is a greatlly reduced net exposure value. Hence the necessity of a slow shutter speed and large aperture.