Meet the GIMP #134: Dynamic Range Therrory
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(Mobile version tomorrow)
The German word “Therrorie” was coined by a kid in a Physics lesson of my late colleague Helmut Mohr in Hamburg. It is what it sounds like – and today’s video is full of it. No GIMP, no images, only the blackboard and me talking. Please consider this as a WARNING.
We had a lively discussion in the forum about the theory behind making images, circling around the term “dynamic range”. There is a big difference between light and dark parts of our world, often more that a camera can catch. And nearly always more than fits onto paper or a computer screen.
The process of squeezing this big range into the small output range is called Post Processing. Either you do it via RAW anf GIMP – or the smart chip in your camera does it while saving your iage as JPEG. What I forgot to say – if you do it, you can redo it. The RAW file still exists. If the chip does it, the RAW file is discarded and you are stuck with the version of the image made by the chip.
I got a lot of information about this subject from a wonderful paper by Karl Lang at Adobe(R). Worth to download and read, even if you decide to skip the video this week.
02:04 Orders of Magnitude
04:00 How much light is in a scene? (Dynamic range ramp up)
06:00 There is no black and white
06:30 Dynamic range of a scene
06:50 Dynamic range of LCD and prints
08:50 Dynamic range of the camera
09:50 Exposure = slide the dynamic range
11:05 Post processing by the camera
12:15 RAW -> GIMP -> print
13:00 Slides and egatives in analog photography
15:05 A source at Adobe(R)
15:15 8 Bits – a problem (sometimes)
17:10 Why is it possible to make images? Because our eyes are no camera and our brain no computer.