Commons:Exif/pt-br

Fotografias tiradas com uma câmera digital provavelmente serão imagens JPEG com dados Exif incorporados, com data e hora em que a foto foi tirada, configurações de exposição, distância focal, etc., e coordenadas de localização, se o dispositivo tiver um GPS. Também é possível adicionar diretamente marcações (tags) de informações Exif a uma imagem, embora as informações sobre, por exemplo, autor e direitos autorais devam ser declaradas explicitamente na página de descrição do arquivo, e o uso de marcações de direitos autorais é obrigatório no Wikimedia Commons.

Objetivo de usar o Exif no Commons

As informações do Exif nos ajudam mantendo todos os tipos de meta-informações diretamente no arquivo, mas nunca substituem uma boa descrição de imagem. Elas são exibidas pelo software MediaWiki na seção “Metadados” da página de descrição da imagem e ajudam a tornar esse recurso útil.

Informação da licença

As informações do Exif são especialmente úteis se você não confia que as pessoas baixem sua mídia do Commons e a reutilizem de acordo com as condições da licença. Assim, as informações de licença são sempre mantidas no Exif de cada cópia da imagem automaticamente. Elas podem ser removidas pelos reutilizadores, mas geralmente é necessário fazer uma “escolha ativa” para isso.

Marca d'água

Marcações visíveis ou marcas d'água dentro de imagens são fortemente desencorajadas no Wikimedia Commons. Informações como “Sr. Zequinha, maio de 2005, CC-BY-SA” não devem ser escritas diretamente na imagem, mas sim nos campos Exif, que também são tecnicamente superiores. Os motivos são os seguintes:

  • Não marcamos nossos artigos da Wikipédia de forma proeminente com nossos nomes no texto do artigo, para que possamos nos afastar do trabalho e deixá-lo falar por si mesmo. O mesmo se aplica às imagens, pelo mesmo motivo de que isso é fundamental para a neutralidade.
  • As marcações pessoais impedem a reutilização de nossas imagens, por exemplo, em colagens e livros. Como nos livros, sempre temos as informações de direitos autorais na legenda da imagem ou no final do livro e, portanto, uma assinatura na imagem produziria redundância no layout da página e seria injusta em comparação com o crédito do autor do artigo.

Orientação (rotação e espelhamento)

Veja também: Commons:Rotation

Os dados Exif podem armazenar uma marcação “Orientation” que especifica se a imagem precisa ser rotacionada ou espelhada para visualização. Essas são as mensagens possíveis na seção de metadados em uma página de arquivo:

Valor da marcação Significado
1 Normal
2 Espelhado horizontalmente
3 Rotacionado em 180°
4 Espelhado verticalmente
5 Rotacionado em 90º em sentido anti-horário e espelhado verticalmente
6 Rotacionado em 90° no sentido anti-horário
7 Rotacionado em 90° no sentido horário e espelhado verticalmente
8 Rotacionado em 90° no sentido horário

Outros formatos de metadados

O MediaWiki também é capaz de extrair alguns outros formatos de metadados não Exif, como IPTC IIM ou XMP. Eles são exibidos exatamente da mesma forma que os dados Exif. Esses outros formatos não são tão comuns quanto o Exif, mas permitem o armazenamento de uma variedade muito maior de informações. O XMP tem a vantagem especial de permitir que os metadados sejam traduzidos para vários idiomas.

Formato Tipos de metadados compatíveis
JPG Exif, IPTC-IIM (exemplo), XMP, comentários em arquivo JPEG (segmento COM)
PNG Marcações de texto em PNG, incluindo suporte para iTXt multilíngue (exemplo), XMP (incluindo dados Exif e IPTC, se incorporados ao XMP)
GIF XMP (incluindo Exif/IPTC incorporado ao XMP), comentário em arquivo GIF (exemplo)
OGG Um conjunto limitado de comentários Vorbis “bem conhecidos” (exemplo) e comentários Theora (exemplo) são mostrados.
SVG Elemento <title>, elemento <description> (exemplo). Nota: No momento, os metadados em XML do elemento <metadata> são armazenados, mas não processados
TIFF Exif (exemplo)
PDF Standard "Document Information Dictionary" fields (example), page size, DRM status, and generic XMP fields (PDF specific XMP fields are not currently supported)

Editing Exif fields

Tools

Multi-platform

  • The GNU Image Manipulation Program (GIMP) is a free software image manipulation program which can handle Exif data. Versions prior to 2.9.4 (unstable) require an Exif viewer plugin be installed.
  • digiKam is a powerful free software image organizer supporting Exif, IPTC and XMP metadata with a visual interface. It also provides an interface for adding GPS coordinates using a map.
  • jhead and ExifTool are command line tools helpful for batch editing Exif metadata, and can display and edit XMP, IPTC and Exif and other metadata.

Mapivi (open source) is a picture manager which is able to add, edit, search and remove image meta information as Exif and IPTC.

MAT2 is free, cross-platform software for removing metadata from various file types, including images, audio, and documents. It offers both a command-line interface and an optional GUI extension for Dolphin, the KDE file manager. These come with most GNU/Linux distributions and are also available for other unices, macOS and Windows.

In-browser

  • Commons:QuickEXIF, a user script that allows Commons users to edit select EXIF metadata fields on JPG files, in-browser without leaving the filepage.

Linux/Unix users

  • In text console you can use ExifTool or exiv2.
  • Geeqie Image Viewer, an open-source fork of GQView for GNOME, is a graphical program that allows one to view image files and edit Exif metadata. Some key word tags are pre-defined and may be quickly selected with check-boxes, but a free-form text box allows entry of arbitrary key words. Batch processing of collections of images is also possible.

Many free image programs, like the DigiKam digital camera manager and the general purpose image viewer Gwenview (both KDE based), can handle Exif as well.

App Store users

  • Metapho displays and edits photo metadata including date, file name, size, camera model, shutter speed, and location. It's available for iPhone (iOS), iPad (iPadOS), Mac (macOS), and Apple Vision Pro (visionOS).
  • Apple's Shortcuts app can be used on iOS and macOS to remove metadata without third-party apps. A pre-made shortcut can be added that integrates with the Share Sheet to remove metadata like location and camera details from one or more images at once.

macOS users

  • Apple's Photos application can view the camera information and can be used to edit title, date, time and keywords.
  • JetPhoto can be used to add GPS data to a photoalbum. JetPhoto uses timestamp information to correlate tracking data from a GPS device with the timestamps on the photo. JetPhoto is freeware so there is no charge but it does not appear to be open source. Keywords and titles can be edited but no other information.
  • Reveal can be used to view and edit Exif summary and exposure data.
  • ImageOptim can quickly and simply remove Exif data.

Windows users

  • Windows 7 and later include "File Explorer" which can edit certain EXIF fields including "Tags", "Title", "Authors" and "Comments".
  • Programs GeoSetter (freeware) and Konvertor (freeware) can edit Exif and IPTC fields such as captions, keywords, etc.
  • Programs XnView (free for non-commercial use), and IrfanView, (free of charge for private use) can edit IPTC fields such as captions, keywords, etc. They can view, but not edit, most Exif fields, like Microsoft Pro Photo Tools[dead link].
  • BatchPurifier LITE (freeware) can completely erase Exif and other JPEG metadata to protect the user's privacy.
  • Metadata++ (freeware) can edit, add and modify any meta (EXIF, IPTC, XMP...)
  • In a CMD window (Win 11: terminal window) you can apply ExifTool.
    This tool is ideal for command-line batch processing, even enabling one to process files recursively throughout multiple folder structures.

Android users

  • Aves Gallery is a picture manager which can edit and remove Exif data. It's also available for Chromebook (ChromeOS) devices.
  • Fossify Gallery is a picture manager which can remove Exif data. It's also available for Chromebook (ChromeOS) devices.
  • Photo Exif Editor can be used to edit Exif data. It's also available for Chromebook (ChromeOS) devices.
  • Exif Eraser detects and erases Exif metadata from JPEG, PNG, and WebP files, providing a full report on what was removed from each image. It's not available for Chromebook (ChromeOS) devices.

ExifTool how-to

Using ExifTool, setting the description, artist, copyright, and licensing information is simple if you are used to the command line. Otherwise, you may want to set up a graphic interface for it, see https://exiftool.org/gui/.

Here the command is split on several lines by "escaping" the line breaks; the "\" should be the last character of the lines (you can add more such escaped linebreaks; the command may flow/wrap onto a new line, but must not contain any linebreaks other than escaped or quoted ones). Text in double quotes in the examples are strings that you want to insert into the Exif data (in the tags specified before the equal sign). The last word of the command line is the file name (the single quotes may be needed if the filename includes whitespace or odd characters).

Applying the Creative Commons CC BY-SA 4.0 International license:

$ exiftool -ImageDescription="This is an example image" -Artist="Artist's name" \
-Copyright="This work is licensed under the \
Creative Commons Attribution ShareAlike 4.0 International License. \
To view a copy of this license, visit \
https://creativecommons.org/licenses/by-sa/4.0/ or send a \
letter to Creative Commons, PO Box 1866, Mountain View, CA 94042 USA." \
-XMP-cc:License="https://creativecommons.org/licenses/by-sa/4.0/" \
'ImageToModify.jpg'

This command will modify four normally empty tags: ImageDescription, Artist, Copyright, and XMP-cc:License.

Another example asserting normal copyright:

$ exiftool -ImageDescription="1988 company picnic" \
-Artist="Camera owner, John Smith; Photographer, Michael Brown; Image creator, Ken James" \
-Copyright="Copyright, John Smith, 1988. All rights reserved." 'Picnic1988.jpg'

Note that ImageDescription and Artist are in ASCII format. For 2-byte character sets, UserComment can be used instead of ImageDescription.

To view all tags, including duplicates, from the Exif group with their current values:

$ exiftool -a -exif:all 'ExampleImage.jpg'

The exiftool software can read and write metadata for a wide variety of file formats, some of which—such as PNG—don’t support Exif proper. The condition where exiftool sees some metadata in a file does not necessarily indicate that these metadata are Exif namely.

Windows users

Windows XP provides a simple and limited way to modify some Exif fields (refer to ). Right click on the image file, select properties, Summary tab. The simple view enables you to edit XPTitle, XPComment, XPAuthor, XPKeywords and XPSubject from the IFD0 group. Note, that XPTitle is ignored by Windows Explorer if ImageDescription exists and XPAuthor if Artist exists. The advanced view displays a limited number of other tags, but doesn't allow modification.

The free Microsoft Pro Photo Tools allows additional Exif editing, particularly of geolocation data, while the free Microsoft Photo Info allows extensive editing of IPTC/XMP metadata. Both products are discontinued.

The powerful ExifTool is available as a stand-alone Windows executable that may be used as either a drag-and-drop or a command-line utility. Windows users may also install the Perl version of ExifTool, but this requires that a Perl interpreter (such as ActivePerl) be installed.

Display of geolocating Exif metadata on image description pages

GPS data will only be shown if one clicks show extended details as it is not on the list of shown by default fields. Additionally, Upload Wizard, Commonist, VicuñaUploader and the Commons mobile app read the data and add template {{Location}} to the page, thus displaying the geographical coordinates and allowing them to be edited. Files uploaded by other means and containing Exif geolocation data are managed by robot "DschwenBot". See also Commons:Geocoding.

Flickr files

Some Flickr images, when downloaded, lack Exif data due to limitations on free accounts. However, this can be bypassed as follows:

  • Use User:InverseHypercube/flickr_exif.py; or,
  • Copy and paste the Exif data displayed on the Flickr Exif page (Menu "Actions" → "View exif info") to a section on the Wikimedia Commons file page. Afterward, the section on the file page could be deleted and be replaced by a permalink to the old version that contained the Exif data.

Exif data on Commons or in MediaWiki

For images with Exif data, Exif data are displayed on image description pages (automatic "metadata" section at the end of pages), e.g., at File:T-45A_Goshawk_03.jpg#metadata (picture of the day on 2009-09-27 by Lt. J.G. John A. Ivancic/U.S. Navy)

Exif data are stored in the img_metadata field of the "image" table of MediaWiki as serialized PHP data. For File:T-45A_Goshawk_03.jpg, this looks like the following:

a:25:{s:4:"Make";s:5:"Canon";s:5:"Model";s:21:"Canon PowerShot S5 IS";s:11:"Orientation";i:1;s:11:"XResolution";s:13:"4718592/65536";s:11:"YResolution";s:13:"4718592/65536";s:14:"ResolutionUnit";i:2;s:8:"Software";s:15:"QuickTime 7.4.5";s:8:"DateTime";s:19:"2008:06:05 10:47:30";s:16:"YCbCrPositioning";i:1;s:12:"ExposureTime";s:6:"1/1600";s:7:"FNumber";s:5:"35/10";s:15:"ISOSpeedRatings";i:100;s:11:"ExifVersion";s:4:"0220";s:16:"DateTimeOriginal";s:19:"2008:06:04 12:51:32";s:17:"DateTimeDigitized";s:19:"2008:06:04 12:51:32";s:17:"ShutterSpeedValue";s:6:"341/32";s:13:"ApertureValue";s:6:"116/32";s:17:"ExposureBiasValue";s:3:"0/3";s:16:"MaxApertureValue";s:6:"116/32";s:12:"MeteringMode";i:5;s:5:"Flash";i:16;s:11:"FocalLength";s:10:"26000/1000";s:10:"ColorSpace";i:1;s:13:"SensingMethod";i:2;s:22:"MEDIAWIKI_EXIF_VERSION";i:1;}

The field can be retrieved through database dumps or through an Application Program Interface (API).

Sample request through API: query for &prop=imageinfo&iiprop=metadata&iimetadataversion=2. Different file types have different metadata representations. To get a unified representation for all formats that matches the JPEG metadata format, use the &iiprop=commonmetadata option (provided by CommonsMetadata). Last of all, if you want to take file description pages into account, use the &iiprop=extmetadata option.

External resources

Category:Commons image resources/pt-br Category:Exif
Category:Commons image resources/pt-br Category:Exif