Having photographed a rim sherd and taken the work home to compile and describe for the PAS web pages, I recalled the Rim Charts published here – http://potsherd.net/atlas/topics/tools.
The problem being that I did not have the sherd at home with me to measure. It then occurred to me that using the Rim Chart on the screen in Photoshop, I could scale the sherd photograph and simply place it and move it around the chart to get the measurements of diameter etc. See below, the same sherd in 2 positions on the chart.
- Take the photograph, edit as required and place onto the normal scale you use for the PAS web.
- Use the ‘Quick selection’ tool to isolate one of the photographs
- Copy the item with ‘Ctrl+C’ and paste (Ctrl+V) it onto the Rim Chart, you now have a movable layer
- Using the Rim Chart scale, re-scale the sherd to that scale to match size
- Simply move the new layer around the chart to find the fit