Water Window Thickness, NCSC #15, April 17, 1951

Why are there errors in the text?

Optical Character Recognition, or OCR, is a process by which software reads a page image and translates it into a text file by recognising the shapes of the letters (The NINCH Guide to Good Practice in the Digital Representation and Management of Cultural Heritage Materials). We perform OCR on text-based resources, like newspapers, to enable full-text searching.

However, OCR is unlikely to be completely accurate. The level of accuracy depends on the print quality of the original issue, its condition at the time of reformatting (microfilming, digitization), the level of detail captured by scanners, and the quality of the OCR software. Scans of pages with poor quality paper, small or faded print, mixed fonts, multiple column layouts, or damage may result in low OCR accuracy.

The searchable text and titles in this collection have been automatically generated using OCR software. They have not been manually reviewed or corrected.