Editing Engineer's blue (section)

==History==
[[Joseph Whitworth]] popularized the first practical method of making accurate flat surfaces, during the 1830s, by using engineer's blue and [[hand scraper|scraping]] techniques on three trial surfaces. Prior to his scraping technique, the same three plate method was employed using polishing techniques, giving less accurate results. This improvement led to an explosion of development of precision instruments using these [[surface plate|flat surface]] generation techniques as a basis for further construction of precise shapes.