--- title: Why Two Fabric Measurements Disagree | Sewlore tags: #sewing #measurement author: [Sewing Selami](https://image.docswell.com/user/3130291) site: [Docswell](https://www.docswell.com/) thumbnail: https://bcdn.docswell.com/page/KJ4WXZW271.jpg?width=480 description: An eight-page illustrated sewing lesson on comparable readings, percentage denominators, stretch and recovery, two-axis PDF pattern print scale, signed care changes and rectangular area. Includes worked hypothetical examples and a reusable measurement record. No fabric or printer experiments were performed for this lesson. Prepared for Sewlore with AI assistance from OpenAI Codex. Use the related Sewlore PDF Pattern Print Scale Checker and printing guidance: https://sewlore.com/pages/pdf-pattern-print-scale-checker published: October 18, 26 canonical: https://image.docswell.com/s/3130291/KL3293-why-two-fabric-measurements-disagree --- # Page. 1 ![Page Image](https://bcdn.docswell.com/page/KJ4WXZW271.jpg) SEWLORE / FIELD NOTES 01 AN ILLUSTRATED SEWING LESSON SAME MARKS Three conditions Why two fabric measurements disagree Check the reference, direction and denominator before deciding what a percentage means. Stretch and recovery / PDF print scale Paired care readings / A reusable record Original / 100 mm Stretched / 125 mm After release / 103 mm One sample. Three different questions. Prepared for Sewlore | Version 1.0 | 17 October 2026 AI-assisted educational resource. All worked values are hypothetical. # Page. 2 ![Page Image](https://bcdn.docswell.com/page/LE1YNRYK7G.jpg) SEWLORE / FIELD NOTES 01 / COMPARABLE READINGS First check what was actually compared. A different number may come from a different reference or condition. The arithmetic alone cannot identify the cause. 01 SAME MARKS 02 SAME DIRECTION Keep both endpoints. An edge-to-edge reading and a marked span are different comparisons. Label the measured direction. Keep length and width readings separate. 03 04 ONE UNIT Convert explicitly before comparing. A ratio of 20 cm and 190 mm needs a common unit. RECORDED CONDITION Note preparation, care or stretch method, and the interval before the next reading. Continue: Fabric Stretch Calculator and recording guidance Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 02 # Page. 3 ![Page Image](https://bcdn.docswell.com/page/GEWG41GPJ2.jpg) SEWLORE / FIELD NOTES 02 / STRETCH AND RECOVERY 25%, 3% and 88% can all be correct. Original = 100 mm | Stretched = 125 mm | After release = 103 mm. These are invented readings for arithmetic practice. Original 25% STRETCH (125 - 100) / 100 x 100 Compared with the original span. Stretched 3% RESIDUAL GROWTH (103 - 100) / 100 x 100 Compared with the original span. After release 88% Extension = 25 mm Recovered length = 22 mm RECOVERED EXTENSION (125 - 103) / (125 - 100) x 100 Compared with the added extension. If no extension was entered, recovered extension is undefined. Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 03 # Page. 4 ![Page Image](https://bcdn.docswell.com/page/47ZL2PL6J3.jpg) SEWLORE / FIELD NOTES 03 / PDF PATTERN PRINT SCALE Check the width and height separately. A hypothetical 100 x 100 mm test square prints as 98 mm wide and 101 mm high. Negative scale error means smaller. AXIS SCALE ERROR CHANGE Width 98% -2% -2 mm Height 101% +1% +1 mm Measured 98 x 101 mm Diagram preserves the stated proportions. Error = (measured - intended) / intended x 100. One uniform zoom change cannot make both unequal axis ratios equal to 100%. Recheck the reference marks, file format, paper size, PDF viewer and printer settings. Print another test page before the full pattern. Target width: 100 mm Open Sewlore's PDF Pattern Print Scale Checker Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 04 # Page. 5 ![Page Image](https://bcdn.docswell.com/page/YJ6WVMWLJV.jpg) SEWLORE / FIELD NOTES 04 / PAIRED CARE READINGS Area change is a product, not a sum. Use the same marked directions before and after. Positive contraction means smaller; negative contraction means expansion. BEFORE 20 x 20 cm AFTER 19 x 19.5 cm LENGTH WIDTH AREA +5% +2.5% +7.375% Retained area fraction = (19 / 20) x (19.5 / 20) = 0.95 x 0.975 = 0.92625 Area contraction = (1 - 0.92625) x 100 = 7.375% Adding 5% + 2.5% gives 7.5%, which counts the corner overlap twice. Use the area calculation only when both pairs of dimensions describe the relevant flat rectangles. Abstract rectangle, not a tested specimen. Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 05 # Page. 6 ![Page Image](https://bcdn.docswell.com/page/GJ5MDZMMJ4.jpg) SEWLORE / FIELD NOTES 05 / UNITS AND BASELINES Name the starting point of every percentage. A percentage from the previous reading and a percentage from the original reading answer different questions. HYPOTHETICAL SEQUENCE CHECK UNITS FIRST 20.0 cm > 19.0 cm > 18.8 cm COMPARISON DENOMINATOR CONTRACTION Original to first 20.0 cm 5% First to second 19.0 cm 1.0526% Original to second 20.0 cm 6% 20 cm = 200 mm Compare 200 mm with 190 mm: 5% contraction. Do not divide 190 by 20 while leaving their different units unstated. Preserve the original readings. Round for display at the end; calculator digits do not add precision to a ruler reading. Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 06 # Page. 7 ![Page Image](https://bcdn.docswell.com/page/9E298R9R7R.jpg) SEWLORE / FIELD NOTES 06 / YOUR REUSABLE RECORD Keep the method beside the numbers. Copy this record for each comparison. Leave fields blank until you have real readings; do not copy the example values as observations. Sample or file ID Question Stretch / recovery | Paired care change | Print scale Direction and reference Unit and original reading Later readings and times Conditions and settings Retain your notes locally. This lesson needs no uploaded sample data. Hypothetical values. No physical fabric or printer tests were performed for this lesson. Open the free Sewlore measurement log SEWLORE / 07 # Page. 8 ![Page Image](https://bcdn.docswell.com/page/D7Y46D45EM.jpg) SEWLORE / FIELD NOTES 07 / CHOOSE YOUR NEXT STEP One record. The right calculation. A clear limit. Start from the question you need to answer, then use the corresponding reference. Pattern-specific instructions take priority. A STRETCH OR RECOVERY Fabric Stretch Calculator Keep original, stretched and released spans plus the release interval. B PDF PRINT SCALE PDF Pattern Print Scale Checker Measure both axes, check settings, then print a fresh test page. C PAIRED CARE CHANGE Fabric measurement methods guide Keep paired units, baseline and method. Area needs the rectangle assumption. These calculations describe the readings entered. They do not establish garment fit, certify a textile procedure or identify the physical cause of a change. Prepared for Sewlore with AI assistance from OpenAI Codex. Vector diagrams are programmatic. Version 1.0, 17 October 2026. Hypothetical values. No physical fabric or printer tests were performed for this lesson. SEWLORE / 08