Level II NDT Inspector and owner of NDT and Inspection Solutions (NIS), Jannie de Beer shares a challenging yet amusing obstacle many faced in NDT before technology got the better of us. Jannie’s experience in NDT dates back to 1989 when he was a Radiographer at the Matimba Power Station in Ellisras. He is now a Level II Inspector with experience and qualifications in the four conventional NDT methods; Magnetic Particle Testing ( MT), Ultrasonic Testing (UT), Liquid Penetrant Testing (PT) and Radiographic Testing (RT)…
Pin-hole photography was an experiment tried and tested by many Radiographers years ago, before digital cameras and in times when economies were not strained as they are today. How many radiographers of today have tried to take a pinhole photograph? Back in the day, before digital cameras and smart phones that can take countless instant photographs were developed, a pinhole camera made with a cardboard box could be used to photograph objects around us.
The lens of the camera was made by cutting a 50mm hole in the box and closing it with a black (exposed) radiograph and then making a pinhole in this black exposed radiograph to ensure light was emitted only though the little hole. The pinhole was closed with another piece of exposed black film to act as the shutter. The camera was then ready. In the darkroom, an unexposed radiographic film was placed in the box opposite the camera lens (pinhole) at a slight curve. The box is made light tight before taken out of the darkroom.
The camera was crudely aimed at an object and the shutter then opened. Depending on the strength of the sunlight, the exposure time for the picture could be between 10 and 40 minutes. At this point the camera should not be moved, the same would apply if taking a selfie. The best results were obtained when doing hand developing and the density adjusted manually by longer or shorter time in the developer.
The result was a “negative” of the object the same way as was possible with a conventional camera at the time.
‘Age Old Techniques of ‘Pinhole Photography’
Drawing of the Inside of a Pinhole box
A modern take on pinhole photography
The antiques of photography
Inside look of an actual Pinhole Box