# Recoll user manual
Index configuration

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### Index case and diacritics sensitivity

As of Recoll version 1.18 you have a choice of building an index with terms stripped of character case and diacritics, or one with raw terms. For a source term of `Résumé`, the former will store `resume`, the latter `Résumé`.

Each type of index allows performing searches insensitive to case and diacritics: with a raw index, the user entry will be expanded to match all case and diacritics variations present in the index. With a stripped index, the search term will be stripped before searching.

A raw index allows for another possibility which a stripped index cannot offer: using case and diacritics to discriminate between terms, returning different results when searching for `US` and `us` or `resume` and `résumé`. Read the section about search case and diacritics sensitivity for more details.

The type of index to be created is controlled by the `indexStripChars` configuration variable which can only be changed by editing the configuration file. Any change implies an index reset (not automated by Recoll), and all indexes in a search must be set in the same way (again, not checked by Recoll).

If the `indexStripChars` is not set, Recoll 1.18 creates a stripped index by default, for compatibility with previous versions.

As a cost for added capability, a raw index will be slightly bigger than a stripped one (around 10%). Also, searches will be more complex, so probably slightly slower, and the feature is still young, so that a certain amount of weirdness cannot be excluded.

One of the most adverse consequence of using a raw index is that some phrase and proximity searches may become impossible: because each term needs to be expanded, and all combinations searched for, the multiplicative expansion may become unmanageable.

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