HDR
(High dynamic range)
-
1. HDR is allowed in TTG photographs, BUT...
. . . all of the exposures being combined in an HDR photograph must meet all of TTG’s requirements for combining exposures, including the “one-second” rule in P5.
P5 means that when the photographer is choosing to combine exposures, it is impossible to make a TTG-qualified photo in which there is more than one second between the start of the first exposure and the start of the last exposure.
-
2. How HDR is defined on this website
On this website the term “HDR” refers to combining multiple exposures made with different brightness choices to compensate for cameras’ limited dynamic range compared to the human eye.
Many smartphones do some form of HDR by default in most lighting conditions, and if the resulting photographs meet the Trust Test — including P5 — they can qualify as TTG.
-
3. HDR is never necessary for a photograph to qualify as TTG
Combining exposures to increase dynamic range is never necessary to meet the Trust Test.
Any normal, functioning camera or device can capture a wide enough dynamic range to meet the requirements of P7.
Even color transparencies — “slides” — are eligible for TTG, and they have a much narrow dynamic range than do digital photographs.
-
4. Excessive HDR effects and/or tone-mapping can disqualify a photograph from TTG
An HDR photograph will fail to meet P7 if the photograph would not meet rinairs for not misrepresenting brightness relationships.
From the rinairs perspective, many gatekeepers of trusted image sources might agree with the ancient Chinese proverb saying that “Anytime the viewer can detect that HDR was used, it means it is being used to excess.”