Monday, March 13, 2006

High Dynamic Range Images

The acronym HDR stands for High Dynamic Range (32 bit editing)

photograph by Micheal Riechmann
In Adobe's implementation within Photoshop CS2 this is accomplished by using a series of photographs which one takes in the same manner as with previous blending techniques, and then using floating point 32 bit (per channel) math, merging these files automatically into one huge high dynamic range image. Reading Michael Riechmann"s tutorial"Merge to HDR in Photoshop CS2" intrigued me, so I began investigating further. Industrial Light and Magic developed the OpenEXR format in response to the demand for higher color fidelity in the visual effects industry. Roger Clark has done some thorough investigation comparing the dynamic range of digital, transparency, and print films and Norman Koren has also done some exhaustive testing with RAW format conversion and tonality.It's all very intriguing, if only we had printers that were capable of better than 8 bit printing!

Addendum: Photomatrix is an independent software for merging multiple exposures in the same way (or better?) than Photoshop CS2 for high dynamic range images.

Also it has been pointed out to me that the Canon imagePROGRAF iPF5000 can print 16 bit, however the Product Specifications is a little loosely phrased "The Plug-in facilitates the printing of 16-bit images by processing the data outside the conventional driver and sending the data directly from Photoshop to the printer, dramatically increasing gradations and as a result, overall image quality". Does this mean it prints 16 bit or downsizes to 8 bit before going to the printer?

1 comment:

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