Ordnance Survey Maps - 25 inch 1st edition, Scotland, 1855-1882

Introduction

Map content, printing and colouring

In this section

Detailed map content

Detail of 25 inch map showing buildings
Town detail from Alva,
Clackmannanshire.

The Ordnance Survey 25 inch maps are a standard topographic authority, depicting practically all human and natural features in the landscape with great accuracy. As for the six inch maps, every road, railway, field, fence, wall, stream and building is shown. There are over 10 different symbols for types of woodland, and uncultivated ground is distinguished into marsh, bog and rough grassland.

The 25 inch scale is four times larger than the six inch, and shows more features in a clearer way:

Acreages and Books of Reference

Extract from a Book of Reference
Detail from a Book of Reference.

The 25 inch maps record acreages of all land parcels. Land parcels were numbered consecutively within each parish, and acreages of fields were recorded in separate Parish Area Books or Books of Reference. For all of Scotland, apart from Orkney and Shetland, these Books of Reference include land use information. On the map 1.0018 square inches on the map equals one acre on the ground.

Printing

Unlike the six inch and one inch maps that were engraved on copper plates, the 25 inch maps were produced by zincography.

Zincography was significantly cheaper, corrections were easier to make, and it was suited to the bold lines and large fonts of the 25 inch scale. The process involved drafting a manuscript plan with litho transfer ink on tracing paper, and the impression transferred to a prepared zinc plate. The zinc plate was then etched with nut galls and phosphoric acid, cleaned, and litho printing ink applied for printing impressions using a hand press.

Lithographic stones had been used at Ordnance Survey from the 1840s, but zinc plates increasingly replaced them from the 1850s. Zinc plates had the advantages of being lighter, and impressions from other copper or zinc plates could be easily copied onto them through electrotyping.

From the 1880s, photo-zincography allowed the automatic reduction of 25 inch maps to the six inch scale through photographic methods, allowing further economies in map production. For this reason, the 25 inch maps developed a bold style and large lettering suitable for reduction to a quarter of the size.

Colouring

Not all sheets were coloured. Those that were coloured used:

The colour was applied by hand, initially by boys paid on a piece work basis, and later by women.

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