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Check |
What it does |
How to fix |
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Check having any jacket |
Looks for Calibre generated jackets listing book metadata such as title, authors, comments and rating. Jackets checked are both those from the latest versions of Calibre, and those “legacy” jackets generated using versions of Calibre prior to 0.6.50. The “newer” jackets are able to be identified by a metadata tag in the xhtml. Use this check if you do not want jackets in your books to identify those to remove. |
Should you wish to remove the jackets, use the Modify ePub plugin or edit manually using Tweak ePub or Sigil. |
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Check having legacy jacket |
Looks for Calibre generated jackets using versions of Calibre prior to 0.6.50. These jackets cause a problem when the file is reconverted, as the Calibre code does not detect them and will duplicate and potentially split them. Use this check if you do not want the legacy jackets, or intend to reconvert in future and wish to avoid issues. |
Should you wish to remove the jackets, use the Modify ePub plugin or edit manually using Tweak ePub or Sigil. |
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Check having multiple jackets |
Looks for ePubs containing multiple Calibre generated jackets. Multiple jackets will occur if an ePub prior to Calibre 0.6.50 is reconverted. Note that the multiple jackets could be multiple legacy jackets, or a combination of legacy and the new jacket. Use this check if you want to cleanup your books to avoid multiple jackets which will have potentially conflicting information. |
Should you wish to remove the jackets, use the Modify ePub plugin or edit manually using Tweak ePub or Sigil. |
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Check missing jacket |
Looks for ePubs that have no jacket. Use this check if you like to have jackets in your ePubs and want to identify those books in your library that do not yet have one. |
Reconvert using the “Insert metadata as page at start of book” option |
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Check missing container.xml |
Each ePub to be valid requires a META-INF/container.xml file, which points to the .opf manifest file. Use this check to find invalid ePubs in your library. |
Reconvert from another format or fix the ePub content using Tweak ePub |
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Check invalid namespaces |
On rare occasions you may find ePubs that have been manually or invalidly constructed and have invalid namespace declarations within the container.xml or .opf manifest files. These no not conform to the ePub specification and will likely have issues when used with other tools or plugins. Use this check to find invalid ePubs in your library. |
Reconvert from another format or fix the ePub content using Tweak ePub |
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Check manifest files missing |
If the ePub has been manually tweaked, it is possible that someone deleted a file from the directory but did not remove the entry from the .opf manifest xml file. Most tools will ignore missing files when viewing or editing that ePub, however it cannot be guaranteed that is always the case. It could also be from a typing error if the manifest was manually edited or the file renamed afterwards. Use this check to find potentially invalid ePubs in your library. |
If the files missing are important, you will need to locate and add them using Tweak ePub. If the files are not needed, use the Modify ePub plugin to cleanup the manifest or edit manually. |
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Check unmanifested files |
The ePub may contain files that are not listed in the .opf manifest. These could be from incorrect matching names in the manifest, from orphaned files that should be deleted, or from third party tools that leave “cruft” inside the ePub file. Note that iTunes plist and Calibre bookmark files are explicitly ignored by this check. Use this check to find ePubs carrying unused files or invalid manifests. |
Use the Modify ePub plugin to either add files to the manifest or remove them from the ePub. Alternatively you can edit manually using Tweak ePub or Sigil. |
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Check iTunes plist files |
When viewing an ePub via iTunes, it will insert a playlist file inside the ePub. This file can be considered “cruft”, particularly if you do not intend to use iTunes to view your ePubs in future. Use this check to find ePubs carrying iTunes cruft. |
Use the Modify ePub plugin to remove these files, or remove manually using Tweak ePub. |
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Check Calibre bookmark files |
When viewing ePub files in Calibre, it will insert a bookmarks file similar to iTunes above storing your last reading position and any bookmarks added. You can disable this feature of the viewer in the viewer preferences. Use this check to find ePubs carrying Calibre cruft. |
Use the Modify ePub plugin to remove these files, or remove manually using Tweak ePub. |
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Check Adobe .xpgt margins |
ePubs that have been created using Adobe tools will contain a .xpgt file that enforces margins. These are in conflict with the traditional css styles and can cause wasted space when viewing on devices. Recent versions of Calibre when converting will zero any margins in such a file. Use this check to find ePubs that may not view acceptably on your device/reader. |
Use the Modify ePub plugin to remove all margins from the .xpgt files, reconvert using Calibre or remove manually using Tweak ePub or Sigil. |
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Check TOC with <3 entries |
The toc.ncx file within an ePub defines the content entries available using the TOC function of your viewer/reader on some devices. The TOC can be built by Calibre during a conversion, provided it can detect the necessary headings, similar for Sigil. An ePub that does not have a “proper” TOC probably only has a single entry of “Start Here” or similar. Use this check to find ePubs that may required TOC being added or rebuilt. |
To rebuild the TOC, reconvert using Calibre to detect the headings if available, or use Sigil to edit and build a structure based TOC. |
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Check embedded fonts |
Some ePubs carry embedded fonts as .ttf or .otf files, to ensure that their content is rendered with a font representing all the characters they contain. Some devices may not support embedded fonts. Use this check to find ePubs that carry embedded fonts. |
Edit manually using Tweak ePub or Sigil. |
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Check DRM |
Certain Calibre features will not work with books that are DRM encrypted, such as conversions. Use this check to find ePubs that are encrypted with DRM |
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Check inline Calibre cover |
When converted using Calibre a titlepage.xhtml file will be added with a cover image. When you send to your device, this cover can be replaced with the latest image associated with the book in your library. Use this check to find ePubs that can have the latest Calibre cover displayed on your device. |
To add a Calibre cover, reconvert (may be added to Modify ePub plugin in future). |
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Check no inline Calibre cover |
Use this check to find ePubs that will not display the Calibre cover |
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Check Calibre conversion |
When converted using Calibre, metadata will be inserted in the ePub to indicate that Calibre was involved in the process. An ePub that has previously been converted by Calibre is probably “safe” to convert again to apply changes. Use this check to find ePubs that are probably safe to reconvert. |
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Check not Calibre conversion |
If the ePub has never been converted using Calibre (such as retail ePubs) then the internal structure and .css files will reflect those of the original tool used to create it. Performing a Calibre conversion may result in undesirable changes to the ePub in some circumstances and should be treated with care to reverse if it goes wrong. Use this check to find ePubs that should be converted with care. |
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Check |
What it does |
How to fix |
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Check Cover by file size |
Looks for covers that are above or below a threshold size. A very small size may indicate a very poor quality or highly compressed cover. A very large size may make books slow to navigate in Calibre and result in large conversions. Use this check to find covers that are not of sufficient quality. |
Replace covers using metadata download, drag/drop from a web page or extract from the book format. |
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Check Cover by dimensions |
As above but uses the dimensions of the image rather than physical file size |
As above |
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Check |
What it does |
How to fix |
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Check title sort |
The title sort is used by Calibre to order your books on screen when sorting by the title column. It is generated automatically when you edit the book title but can be manually overridden in the Edit Metadata dialog. When the title sort differs from that which Calibre would generate, the Edit Metadata dialog will display the field background in red. Use this check to find books which would display a red title sort field in Edit Metadata indicating the title sort is out of sync. |
Use the bulk metadata edit dialog or edit the titles individually. |
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Check author sort |
The author sort is used by Calibre to order your books on screen when sorting by the authors column. It is frequently also used for other features such as collection generation. It is generated automatically when you edit the book authors but can be manually overridden in the Edit Metadata dialog. When the author sort differs from that which Calibre would generate, the Edit Metadata dialog will display the field background in red. Use this check to find books which would display a red author sort field in Edit Metadata indicating the author sort is out of sync. Note that there are cases where this is desired to be different such as when there are multiple authors for a book but you want it listed within a series for the main author. |
As above |
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Check ISBN |
The ISBN field must conform to certain validity for ISBN-10 or ISBN-13. It is used primarily for metadata download lookups. When the ISBN is invalid, the Edit Metadata dialog will display the Ids field background in red. Use this check to find books with an invalid ISBN. |
Use the Extract ISBN plugin or edit manually to replace the ISBN. You can also use a metadata download to replace it. |
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Check pubdate |
When a book is first added to Calibre, the pubdate column is set to the date/time the book was added (rather than blank). Retrieving metadata will update this column if metadata is found. Use this check to find books with a pubdate that has not been changed from when the book was first added to Calibre. |
Use a metadata download to update the pubdate field or edit manually. |
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Check duplicate ISBN |
Looks for multiple book entries in Calibre that have the same ISBN value. This situation indicates either you have duplicate records in your database, or that one of the books has an incorrect ISBN. Use this check to find books that appear to be duplicates by their ISBN only. |
If the books are not duplicates, replace the ISBN as per “Check ISBN” above. If they are duplicates, then merge them using the Edit -> Merge feature of Calibre. |
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Check duplicate series |
This looks at the series names used by your books and identifies any books that match exactly on both series name and index. It is a good idea to ensure your series names are unique and not reused across different author series, or else the Calibre auto-numbering will not work correctly and you cannot use the “Similar Series” feature to see just the books in that particular series. Use this check to find books that are duplicates because of their series name/index, or where two different series have been setup with the same name. |
Use the Manage Series plugin to rename a series, edit manually or use the bulk Edit Metadata dialog. If the books are genuine duplicates then use the Merge feature of Calibre. |
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Check excess tags |
In the configuration screen for this plugin you can specify a threshold limit for how many tags you would like on your books. If you enable tag downloading from sources such as Google books, you will inevitably get a lot of “random stuff” added which can swamp your library. Use this check to find books that have a count of tags exceeding your configured threshold. |
Edit the tags on a particular book, or use the tag browser to rename tags to merge them together. |
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Check HTML comments |
A few devices do not like HTML markup in the comments field when this is attached to the book metadata. Use this check to find books that have a comments field containing html markup. |
Edit the comments manually or download metadata with the “Convert all comments to plain text” option checked. |
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Check no HTML comments |
If you are after consistency you may have legacy comments that do not contain html markup within them. Use this check to find books that have a comments field without any html markup. |
Edit the comments manually or download metadata with the “Convert all comments to plain text” option unchecked. |
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Check authors with commas |
If you prefer to have your authors displayed as “FN LN” then the presence of a comma may indicate an author incorrectly imported as “LN, FN”. Note that you may also have chosen to import a name as “FN LN, Jr” which would also show up in this check. You can modify the search criteria in the plugin preferences. Use this check if you store your authors as “FN LN” and want to detect invalid authors of “LN, FN”. |
Edit the author manually or rename using the tag browser. |
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Check authors with no commas |
If you prefer to have your authors displayed as “LN, FN” then the lack of a comma may indicate an author incorrectly imported as “FN LN”. You can modify the search criteria in the plugin preferences. Use this check if you store your authors as “LN, FN” and want to detect invalid authors of “FN LN”. |
Edit the author manually or rename using the tag browser. |
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Check titles with series |
When importing books if your regular expression is incorrect you may have books that contain series information in the title, such as “Title – Series[1]” etc. This is a quick check that looks for either hyphens or numeric values in the title which might indicate this situation. This check will product a number of false positives. You can modify the search criteria in the plugin preferences. Use this check as a quick review after a bulk import to verify your filenames matched your regular expression correctly for the title and series fields. |
Edit the title manually or use the bulk edit metadata search replace. |
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Check title case |
Calibre offers a title case function to convert book titles to an official casing as often used by libraries, publishers etc. For instance words like “the” should have a lowercase t etc. After importing filenames you might have all lowercase names or other undesired combinations. There can of course be situations where you may prefer the casing to match that of the official title. Use this check to find titles which are not consistent with the “title case” approach to naming. |
Use the bulk edit metadata screen to apply title casing. Or edit individually and use the right-click menu to assign title casing. |
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Check |
What it does |
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Check and repair book sizes |
Calibre when you add a book will store in the database the size of the file in bytes. This is used just for informational purposes for the Size column. If you edit your book directly outside of Calibre, such as using Sigil with the Open With plugin, then the size will not be updated in the database. Use this check to find books with a format that has changed in size since it was added to Calibre, and update the size value in the database. |
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Cleanup .opf files/folders |
If you use the save to disk feature for your device, and then remove books, you may find you have orphaned cover jpg and metadata opf files in that folder structure. This can build up over time with undesirable effect. It is intentional by Calibre to not remove these files as a conservative approach to only removing the actual book format. Note that you should never run this feature against a Calibre library, because “Empty Book” entries fall into this exact criteria, and would result in those being removed and your database being out of sync. Use this check to remove all .opf or .jpg files where they are the only files in that folder. If after removal the folder is now empty, it is removed as well. |
For any problems, issues or obtaining the latest version of this plugin, please refer to the Calibre Quality Check plugin forum thread.