Notice the words “dynamic range higher than what is considered to be standard dynamic range”.
In image editing, somewhere around 8 stops is considered “standard”, based on the number of discernible stops (doublings of linear RGB values) from “just above black” (perhaps "L=0.5 or “L=1.0” on a scale from 0 to 100 is a good number for this), to the integer-encoded max of 255 (or 65535/etc depending on the bit depth of the image).
OK, a lot of people will say, well, that’s just Wikipedia and those people make huge mistakes (something I haven’t found to generally be the case, but of course I haven’t double-checked the facts in every single Wikipedia article). So putting anything Wikipedia says to one side, how about this article by Greg Ward:
http://www.anyhere.com/gward/hdrenc/pages/originals.html
Quoting the first sentence of Ward’s article: "The following examples were used to compare the following High Dynamic Range Image formats: OpenEXR, Radiance RGBE and XYZE, 24-bit and 32-bit LogLuv TIFF, 48-bit scRGB, and 36-bit scRGB-nl and scYCC-nl. "
OK, so what does Ward mean by HDR image format? He means an image format that can hold more than the dynamic range that fits into 8/16-bit integer file formats such as png and jpeg.
Two commonly used HDR image formats are OpenEXR and high bit depth floating point tiffs. GIMP (and darktable, PhotoFlow, etc) can open and export both file formats, fwiw, and also can operate on channel values that are >1.0f and produce correct results, assuming of course that the data is actually meaningful data in the first place!
The video display industry is using “HDR” to market their new monitors with a greatly increased dynamic range compared to “standard” monitors. And someday those new monitors will perhaps become commonplace. But for image editing, right now apparently they have limitations.
Just because the video display industry is using “HDR” to market their new display technology, doesn’t mean suddenly anyone and everyone who uses “HDR” to mean anything else is suddenly using the wrong terminology.
Which brings the topic back to the question:
@anon11264400 - why is data (actual data) with channel values >1.0 “data” in Blender and Nuke, and “non data” in GIMP?