1401. What’s the point of Q4?
In light of Characteristic #4 of trusted photographs (“one scene”)...
Q4 ensures that when the subject has change or motion in it:
. . . TCQ photographs of that subject do not depict more than one scene and that they do not depict a scene that never occurred.
Those things are addressed by the four requirements in the last paragraph of Q4: satode , motarri, and the prohibition of ghost objects and SMP effects.
1402. Why does the subpage of Q4 say that change or motion in the scene is typically incompatible with combined exposures and long exposures when making TCQ photographs?
Because combined and long exposures of changing or moving scenes can produce TCQ-disqualifying visual effects—
— and apart from cropping them out, those effects usually cannot be removed no matter how many of TCQ’s Allowable Changes are applied.
Q4 | Q4 subpage
1403. So the four requirements in the last paragraph of Q4 are there to prevent “disqualifying visual effects”?
Without all four, it would be easy to make photographs that depict “more than one scene” or that “depict a scene that never occurred” (see #1401 above).
The four requirements in the last paragraph of Q4 each address potential visual effects that would disqualify the photograph from Q4’s “one scene” requirement:
1. satode issues are most likely to occur when combined or long exposures are used to record fireworks, lightning, and other “bright lights in dark surroundings.”
2. motarri issues occur when long exposures are used to record moving objects
3. ghost objects occur when combined or long exposures are used to record scenes in which stationary or slow-moving things appear in different positions during exposure
4. SMP effects occur when multiple exposures (or multiple bursts of strobe light) are used to record a scene with movement in it.
1404. When will photographers have trouble meeting Q4?
Issues with Q4 most often arise when the photographer manually selects particular exposure settings to shoot a changing or moving subject.
But any photographer who is advanced enough to manually select those exposure settings can usually understand the four requirements in Q4 (listed in #1403 above) and consider their options.
1405. What about meeting Q4 when a smartphone is set to Automatic?
With most normal and daytime subjects, smartphones set to Automatic will meet Q4.
But there are some situations — especially involving moving subjects in low light — in which smartphones struggle to reduce or eliminate SMP effects in particular.
It is difficult to avoid these effects (thanks to automated choices made by the device) and it is difficult to remove the effects (apart from cropping them out, which is of course allowed by TCQ; see #6 here).
From #762: “Sometimes the photographer will just have to admit that a photo is ineligible to qualify as TCQ.”
1406. If TCQ photos can only depict “one scene,” why does TCQ allow at all for combining multiple exposures?
Because millions of non-deceptive photos are made every day by combining multiple exposures for a variety of reasons, including to increase dynamic range, to increase resolution, and to increase depth of field.
The changing role of combined-exposure photographs
“Combining exposures” is no longer synonymous with “depicting multiple arrangements of the scene” the way it usually was in the film era (see #1410).
What are the limits TCQ puts on combining multiple exposures?
1407. Why doesn’t motion blur disqualify a photograph from TCQ?
Why should it? Genuine motion blur is very familiar to viewers and is not considered deceptive.
1408. But both “ghost objects” and “motion blur” reflect changes in the scene — and both entail some “see-through” of the subject — so why does TCQ disqualify “ghost objects” and allow “motion blur”?
Because the presence of “ghost objects” means that the photo does not depict a “specific arrangement that occurred during exposure,” or satode, as required by Q4.
In other words, “ghost objects” entail the depiction of two or more scenes — that is, two or more arrangements of the subject — which is why they are disqualified by Q4’s “one scene” requirement.
But with “motion blur,” the objects are all depicted in a “specific arrangement that occurred during exposure.”
To use the language from the page on satode:
• A photograph with motion blur depicts what would be depicted in a momentary “glimpse” or “snapshot” of the subject;
• a photograph with ghost objects would not depict what would be depicted in a momentary “glimpse” or “snapshot” of the subject.
1409. How do I distinguish between “ghost objects” vs. “motion blur”?
With TCQ-compatible “motion blur,” much of the object is not see-through but the edges are see-through.
With “ghost objects,” the reverse is true: the edges and features are typically defined clearly, while viewers can “see through” much of the object.
1410. Does the “ghost objects” prohibition of Q4 disqualify what is traditionally considered a “double exposure” of the kind made in the 19th and 20th centuries?
Yes it does (assuming the reference is to having semi-transparent scenes overlap in the same photograph).
Newcomers to TCQ might assume that manipulations of the film era should automatically qualify as TCQ. That is not the case.
The non-manipulation policies of respected news agencies — on whose policies TCQ’s rinairs standard is based — are much more strict in the digital era than they were in the film era, simply because everyone knows that it is so much easier to make undetectable manipulations now than it was back in the film era.
For 19th-century examples of double-exposures and semi-transparent scenes, see #4 in the Key entry on ghost objects.
1411. What about the use of flash during a single exposure, which often illuminates the scene for only a fraction of the total exposure?
Use of flash is usually not a disqualifier from TCQ; see the guide to flash photography.
See also the “Q4” tab on the page “What the public knows about how undoctored photographs work”
The numbering of the FAQ questions will not change, so users can safely make a link to any specific question.