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Limits Formulae - Overview
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Since Hermann Seger devised the Unity Formula system ceramic scientists and educationalists have conducted many tests to discover the upper and lower 'limits' for the various oxides which may occur in a glazes fired to a particular temperature/cone.

These ceramists have usually been in the employ of one or other section of the ceramic industry or are members of the ceramic education fraternity and have conducted their tests with the requirements of that background in mind.

In the cases of industry they have been concerned with the creation of glazes which are durable and stable and which do not have problems such as the leaching of constituent base oxides or colourants whereas when educationalist or ceramic artist have devised limits they may have been more concerned with producing a range of textures and qualities of use in finishing non-functional ceramics.

Consequently there are a number of limit tables available to studio potters and your choice of which limit tables to use must depend on your requirements. If you are producing functional ware then issues of durability, stability, fit, leaching etc will be of importance and may determine which limit tables you should use. These tables will have a much smaller range of, e.g. acceptable Al2O3 and SiO2 limits, than glazes which are not being used as liners in table ware.

Limit Tables Available in Matrix

Matrix comes with a number of limit tables gathered from various sources. These tables may be viewed and edited in the Limits Chart Window.

New tables may be developed and saved from this window.

These tables may also be viewed on the Limit Formula Graph and on the Al / Si Graphs in which the tables displayed may be selected from the windows' Action menu.

Default Limit Tables

When Matrix is booted it will check it's Matrix Options.opt file to see which set of tables to initially use in limit displays.

You may change this default setting by selecting the Options (Preferences) item in the Matrix menu and clicking the Limits tab. More ...

Creating Your Own Limit Tables

You may wish to experiment with the creation of specific limits data which reflect oxide ranges in particular glaze types e.g. maiolica, shino, oilspot, etc., etc. This process is explained in Creating Your Own Limits

Follow these links for more information about:


Overview | Viewing Limits Data on Graphs | Edit / View Limits Tables | Entering New Limits Data | Creating Your Own Limits Data