The collection features Scottish and international architecture, 1930s-1950s. It is made up of 120mm photographs, images printed on postcard, cropped images and published postcards. There are also occasional 120mm photographs joined to make double or even triple images.
There are ca. 2,365 images of Scottish vernacular architecture, of which over half are 120mm photographs, a further 968 are photographs on postcard along with 16 published postcards. Some 188 images relate to photographs of various sizes which have been clipped. Scotland was surveyed between 1937 and 1943 beginning with Caithness in 1937, then Banff, East Lothian, Fife, Mid Lothian, Moray, Caithness, Sutherland and Wigtownshire in 1938. In 1939 Reiach surveyed Ayrshire, Argyll, Caithness, Fife, Stirlingshire, East Lothian, West Lothian and Perthshire. In 1940 he covered Ayrshire, Angus, Kincardineshire, East Lothian, Wigtownshire, Renfrewshire, Ross and Cromarty and Stirlingshire. 1942 saw tours of Argyll, Inverness shire, and undated surveys also exist for Orkney, Roxburghshire, Clackmannanshire, Dumfriesshire, Kirkcudbrightshire and Berwickshire. There are also 104 additional 120mm images of Scotland within the foreign section and 11 British images on postcard marked 'foreign parallels'.
The foreign section contains ca. 1815 images, including ca. 841 120mm photographs, 505 images on postcard, 211 published postcards and 258 assorted size images. The collection is particularly strong in images of Germany, Italy, Sweden and Spain, but there are also images of Greece, Holland, Hungary, Ireland, Norway, Russia (including a le Corbusier envelope containing 7 images), Belgium, Switzerland, North America, France, Finland, Poland and Denmark. Many of the published postcards had been sent by or received by Reiach and can contain descriptions of cities and rough sketches of plans and ideas. He visited South East England in 1929, Italy and Germany in 1933, Sweden in 1934, Norway, Finland, Germany and Switzerland and possibly Denmark in 1934, Germany and the Netherlands in 1935, North America in 1935-6, Russia, Germany Czechoslovakia, the Netherlands, France and Switzerland in 1936 and Germany and Switzerland in 1937 and 1938.