Strong low-resolution spots often challenge detector dynamic range. Profile fitting can sometimes estimate an overloaded reflection from unsaturated pixels, while a short exposure can provide a direct linear replacement. Both need evidence and limits.
This guide follows raw pixels, masks, background, profiles, partials, scale factors and merged intensities. It avoids treating a software number as self-validating.
IUCr integration and data-collection guidance provide the research basis. Numerical cases are invented for teaching and are not detector-operating instructions.
The central spot has forty peak pixels and two saturated central pixels. A supported local profile can estimate its scale from the remaining pixels. If thirty pixels saturate, the same method loses its evidence base and a short linear exposure becomes more important.
This specialist guide belongs to the X-ray Crystallography root. It also connects to The Gold Standard of Education | Learning That Transfers into Life and the How X Works hub. The worked cases are original teaching examples; their numbers are stipulated so that the reasoning can be checked.
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A saturated pixel has exceeded a trustworthy detector-response region. Integrated reflection strength is a processed estimate over peak and background pixels, sometimes using a standard profile. One invalid pixel does not automatically reveal or erase the full reflection intensity.
ROUTE 1 · CHAPTERS 1–5
Define the measurement
Separate detector response, raw profile and integration.
ROUTE 2 · CHAPTERS 6–10
Diagnose overload
Compare linear strength, blooming, overlap and short passes.
ROUTE 3 · CHAPTERS 11–15
Integrate carefully
Handle repeats, partials, background, profiles and uncertainty.
ROUTE 4 · CHAPTERS 16–20
Protect dataset meaning
Track missingness, shells, phasing, damage and exposure brackets.
ROUTE 5 · CHAPTERS 21–28
Report and continue
Preserve masks, replacements, provenance, IUCr sources and sibling routes.
Chapter contents
Define the measurement · Chapters 1–5
Diagnose overload · Chapters 6–10
6. Separate overload from strong but linear
7. Separate overload from blooming
8. Separate saturation from overlap
Integrate carefully · Chapters 11–15
11. Do not select the largest value
13. Account for background subtraction
Protect dataset meaning · Chapters 16–20
16. Separate saturation from missingness
18. Protect phasing and refinement
Report and continue · Chapters 21–28
21. Propagate pixel masks into reflection flags
22. Check contamination around an overload
23. Merge replacements by validity and uncertainty
24. Audit the full measurement trail
25. Check detector corrections
Start with the mechanism, not the symptom. Detector saturation means one or more pixel responses are no longer reliable or linear; integrated reflection strength is an estimate of total Bragg intensity after background and profile treatment. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: A strong spot has three saturated centre pixels but many unsaturated profile pixels. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Keep raw pixel validity, integration method and final intensity estimate separate. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Saturate most of the profile rather than only its centre. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. A saturation threshold belongs to a detector mode, gain setting, exposure and correction state rather than to crystallographic intensity itself. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: The same reflection is linear at short exposure and overloaded at long exposure. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Use calibrated detector specifications and processing flags for the actual run. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Change gain mode while holding incident flux fixed. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
The short answer becomes reliable only when its boundary is named. A reflection intensity is distributed across pixels and images, so one clipped pixel does not equal one known intensity value. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: The central pixel caps at the threshold while tails remain below it. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Display raw counts, mask states and neighbouring background before trusting a merged scalar. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Move the spot across a module boundary. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. Summation adds valid peak pixels after background subtraction; profile fitting scales a standard shape and can sometimes estimate intensity from unsaturated regions. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: A known profile fits the unsaturated tails of a centre-overloaded reflection. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Check how many informative pixels remain and whether the standard profile matches this detector region. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Broaden the spot so the standard profile mismatches. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Start with the mechanism, not the symptom. IUCr integration guidance notes that excluding saturated pixels can permit a reasonable estimate except when most pixels are saturated. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: A spot with two clipped pixels among forty differs from one with thirty clipped pixels. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Record saturated fraction and estimator warning instead of returning an unqualified number. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Increase exposure until the tail pixels also clip. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. A high count is not saturated when detector response remains calibrated and linear below its threshold. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: Reflection A has 800000 counts under a 1500000-count limit; Reflection B hits the cap. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Use pixel-level response status, not a subjective bright appearance. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Lower the detector threshold through a mode change. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
The short answer becomes reliable only when its boundary is named. Some detectors or readouts spread charge or artefacts to neighbouring pixels when overloaded, enlarging the invalid region beyond capped pixels. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: A saturated centre produces a streak that contaminates background pixels. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Apply detector-specific masks and inspect neighbourhood patterns. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Use a detector mode without that blooming behaviour. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. Two nearby linear reflections can overlap without any pixel saturating, while one isolated reflection can saturate. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: A close pair shares profile pixels at modest counts. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Check predicted spot positions, profile model and pixel linearity independently. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Increase exposure without changing separation. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Start with the mechanism, not the symptom. A short exposure can recover strong low-resolution reflections that overload in a long exposure. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: Long pass is 10 s and clips a spot; short pass is 0.5 s and remains linear. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Scale using common linear reflections and preserve exposure, attenuation and detector settings. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Use a different wavelength in the short pass. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. If matched linear reflections give long/short intensity ratios near 19.8, multiply the valid short measurement by the fitted scale rather than the nominal exposure ratio alone. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: A short intensity of 1200 predicts about 23760 on the long scale. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Fit robustly with uncertainty and inspect residuals across intensity and detector position. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Let radiation damage occur between passes. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
The short answer becomes reliable only when its boundary is named. Choosing the largest available measurement biases noise and can retain nonlinear observations. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: Three repeats yield 9800, 10200 and an overloaded cap at 12000. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Exclude or model overload under the method, then combine valid observations with appropriate weights. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Add a weak repeat with high uncertainty. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. A rotation reflection can span several images, and saturation in one partial affects the summed full intensity. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: Four partials contribute 20, 35, 30 and 15 percent; the 35-percent image clips. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Preserve partiality estimates and per-image validity before summing. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Use finer slicing so the same intensity spreads across more frames. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Start with the mechanism, not the symptom. Integrated strength subtracts local background; a saturated or contaminated background region can distort the estimate even when peak pixels are linear. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: An overload streak enters the background rim around a neighbouring spot. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Inspect measurement-box classification and rejected pixels. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Move the box or use an uncontaminated exposure. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. Standard profiles vary across detector position, incidence angle and experimental conditions. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: Tails from a central detector profile are used to estimate an edge reflection and give systematic residuals. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Choose local profiles and inspect goodness of fit, especially for strong reflections. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Change crystal mosaicity during the run. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
The short answer becomes reliable only when its boundary is named. An estimated overloaded intensity usually carries more model dependence than a fully linear direct integration. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: The software returns a number but its standard uncertainty omits profile-shape mismatch. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Flag estimation method and assess residual or replicate evidence. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Compare against a short-exposure linear measurement. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
CHAPTER 16 OF 28 · Protect dataset meaning
16. Separate saturation from missingness
A useful explanation preserves cause, observation and decision. An overloaded reflection was observed but not reliably measured; an off-detector or unexcited reflection has different evidence. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: Both may be absent from the accepted merged table for different reasons. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Preserve rejection categories through completeness and quality reports. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Recover the overload with a short pass while geometry stays unchanged. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Start with the mechanism, not the symptom. Overloads often cluster among strong low-resolution reflections, while weak high-resolution loss has another cause. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: A dataset is complete at high angle but lacks several intense low-angle measurements. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Plot overload counts and accepted replacements by resolution shell. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Shorten exposure only for the low-angle pass. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. Strong low-resolution intensities can be important for molecular replacement, scaling and electron-density interpretation. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: Discarding every overloaded reflection creates a structured evidence gap. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Test sensitivity to recovered, excluded and model-estimated intensities. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Refine with and without the short-pass replacements. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
The short answer becomes reliable only when its boundary is named. Intensity decay across time can mimic scaling trouble but does not turn a linear pixel into a saturated one. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: The same reflection weakens in later frames while never reaching the detector cap. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Plot time, dose proxy, scale and overload status separately. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Reverse collection order in a controlled comparison. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. Two or more exposures can extend usable dynamic range when their linear regions overlap sufficiently for scaling. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: Short, medium and long passes cover strong, intermediate and weak reflections. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Plan overlap, attenuation, dose and orientation so scaling is identifiable. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Remove the medium pass and inspect scale stability. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
CHAPTER 21 OF 28 · Report and continue
21. Propagate pixel masks into reflection flags
Start with the mechanism, not the symptom. A saturated-pixel mask is useful only if integration preserves which reflections touched the invalid region and how the estimator treated those pixels. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: Two reflections share a measurement box; one contains the saturated centre while the neighbour uses background pixels affected by the same masked column. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Trace mask provenance from raw image through shoebox, integrated observation and merged reflection table. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Change the mask radius and compare both reflections’ flags and uncertainties. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. An overloaded spot can disturb neighbouring measurements through blooming, afterglow, dead-time or an enlarged exclusion region even when those neighbours never reach the nominal pixel cap. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: A weak reflection beside a very strong spot has linear peak pixels but a biased local background. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Inspect detector-specific artefact patterns and spatial residuals before accepting the neighbour as an independent valid observation. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Rotate the crystal so the neighbour lands away from the strong spot while preserving resolution. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
CHAPTER 23 OF 28 · Report and continue
23. Merge replacements by validity and uncertainty
The short answer becomes reliable only when its boundary is named. A short-exposure replacement and a model-estimated long-exposure value should not be combined as if they were equivalent repeated direct observations. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: The short pass gives a linear scaled intensity with five-percent uncertainty; profile fitting of the clipped long pass gives a compatible but model-dependent estimate. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Define a precedence or joint model, preserve method flags, and test whether the merged value changes under reasonable weighting choices. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Remove the direct replacement and report how much the final estimate depends on the fitted overload. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. A credible final intensity can be traced from raw pixels through calibration, masks, integration, scaling and merging, with each transformation retaining its reason and uncertainty. The trail should also retain the software version, parameter set and detector calibration identifier that controlled each classification. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: A merged reflection looks plausible but its source observation ID points to an excluded overloaded frame rather than the short-pass replacement. A second analyst can reproduce the scalar only after recovering which exposure and scale model supplied it. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Follow identifiers back to images and processing logs; numerical agreement cannot repair broken provenance. Compare the accepted observation set before and after every threshold change, because the same merged label can hide a different evidence path. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Reprocess with a new saturation threshold and compare the complete trail rather than only the final scalar. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Start with the mechanism, not the symptom. Gain, flat-field, dead-time and nonlinearity corrections depend on detector technology and mode. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Worked case: A nominal count below the hard cap lies in a documented nonlinear regime. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Evidence check: Use calibration provenance and processing software appropriate to the detector. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Changed-context transfer: Process the same frames with an outdated calibration. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Keep the two objects in separate ledger columns. Record detector mode, threshold, exposure, attenuation, saturated-pixel mask, affected reflections, estimation method, replacement source and uncertainty. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Concrete case: A reviewer can trace each final intensity to raw evidence. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Practical check: Keep original flags even after a successful replacement. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Transfer test: Reprocess with a revised threshold and compare classifications. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
CHAPTER 27 OF 28 · Report and continue
27. Use authoritative crystallography sources
The short answer becomes reliable only when its boundary is named. IUCr integration guidance explains summation, profile fitting and estimation from unsaturated pixels; data-collection guidance treats detector dynamic range and overloaded pixels. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Reason through this case: Read https://journals.iucr.org/d/issues/1999/10/00/ba0027/index.html and https://journals.iucr.org/d/issues/1999/10/00/ba0020/index.html. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Audit the claim with this evidence: Check the detector-specific method before applying the teaching examples. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Now change one condition: Compare an older CCD workflow with a photon-counting detector. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
A useful explanation preserves cause, observation and decision. The angular-coverage guide owns where rays can land; this guide owns whether recorded pixels remain linear enough to support integrated strength. State which property is being changed, which box, channel, credential or measurement owns it, and which conclusion is still undecided.
Use this stipulated example: Continue with https://edukatesg.com/portfolio/the-gold-standard-of-x-ray-crystallography-separating-resolution-cutoff-from-detector-angular-coverage/ and the completeness-versus-redundancy sibling. Keep every stipulated value and comparison visible so another reader can reproduce the result without supplying a hidden default.
Verify rather than assume: Return to the X-ray Crystallography root for systematic absences and symmetry questions. Record the definition, version, measurement window or processing rule that makes the evidence relevant, together with any unresolved condition.
Test whether the reasoning travels: Classify the failed measurement before choosing geometry, exposure or integration remedies. Re-run the decision from the changed input instead of copying the earlier label. Explain what changed, what stayed fixed and what the example cannot prove.
Contents · Previous chapter · Return to X-ray Crystallography
Continue through the verified reading route
Resolution cutoff and detector angular coverage
Resolution cutoff and detector angular coverage. Use this when the question is where reflections can land, rather than whether recorded pixels remain linear.
Reflection completeness and measurement redundancy
Reflection completeness and measurement redundancy. Use this to distinguish coverage of unique reflections from repeated observations.
X-ray Crystallography subject guide
X-ray Crystallography subject guide. Return here for symmetry, systematic absences, indexing and the wider experimental route.
Frequently asked questions
Does one saturated pixel make the reflection intensity unknowable?
Not always. Unsaturated profile information may support an estimate, but the evidence weakens as more of the profile is lost.
Is every bright reflection saturated?
No. Saturation is a detector-response classification; a strong measurement can remain within the calibrated linear range.
Why collect a short exposure?
It can recover strong reflections in a linear range while a longer pass measures weak reflections, provided the passes can be scaled defensibly.
Should an estimated overload carry the same uncertainty as a direct measurement?
Usually not without evidence. Profile assumptions, excluded pixels and scaling add model dependence that the record should preserve.
Authoritative sources and further reading
IUCr: Integration of macromolecular diffraction data. Summation, profile fitting and treatment of saturated pixels in integration.
IUCr: Data collection and processing. Detector dynamic range, exposure design and overloaded-reflection context.
Return to the X-ray Crystallography subject guide, The Gold Standard of Education, or the How X Works hub.