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Digital Humanities

This guide provides an overview of Digital Humanities (DH) resources and tools for the SDSU community.

Create: Tools and Areas of DH

Within the Digital Humanities there are many areas of practice. We’ve highlighted 14 of them. Each section tells you a little more about the area and the different tools you can use to begin creating. We’ve focused on the areas first (rather than leading with the tools) to encourage you to think critically about the projects and work you’re interested in doing.

Before starting a new DH project, take time to intentionally consider how you will engage in ethical collaboration. This involves ethical labor practices, as well as clearly defining roles and responsibilities among project partners. See, for example:

Our lists of tools are not intended to be comprehensive. Check out this August, 2019 blog post by Digital Humanities Programs Assistant Jared Zeiders about free alternative tools. And explore this set of Ethical EdTech tools.

Starting in the spring of 2020, the Digital Humanities Center has been hard at work creating a series of tool tutorials, with particular emphasis on audio and video editing tools to support podcasting. We've also got tutorials for project management tools, text analysis, electronic literature & digital storytelling (such as Twine and Scalar), and many more!

Tools

Digital and social annotation allows folks to markup and share various digital content -- webpages, images, etc. Social annotation allows us to expand knowledge production by allowing commenting, tagging, and other activities that can help clarify and expand on existing resources. Social annotation can be a meaningful pedagogical approach, and there are several tools that can be used in the classroom:

  • Annotation Studio - a suite of collaborative web-based annotation tools currently under development at MIT
  • Hypothes.is - designed primarily for the classroom, Hypothes.is enables collaborative annotation to make reading active, visible, and social; can often be integrated into learning management systems, such as Canvas
  • Recogito - an online platform for collaborative document annotation; supports: uploading texts and images, creating annotations, identifying and mapping places in your documents, exporting data in order to re-use it elsewhere, and collaboration

Learn more at our Teaching During Quarantine website.

Crowdsourcing is a practice that connects people with varied skills and resources in order to collaborate on projects and processes. For example, Zooniverse is a platform that connects professional researchers with volunteers in order to enable research that would otherwise be impossible. Explore "Crowdsourcing in cultural heritage: a practical guide to designing and running successful projects," a pre-print book chapter by Mia Ridge (2021).

  • Google Suite - allows for real-time collaboration, most commonly used as Google Docs and Google Sheets; make sure to share publicly: anyone with the link can edit (type directly into the document) or comment (add comments or suggestions via track changes)
  • PYBOSSA - crowdsourcing framework to analyze or enrich data that can't be processed by machines alone
  • Zooniverse - supports multiple crowdsourcing tasks, including categorization, transcription, and drawing

 

Data visualization is the practice of creating graphic representations of information and data. It is a visual way of reading, studying, and interpreting information that can be more accessible. For example, TimelineJS helps users turn chronological information into interactive and visual timelines. Learn more about the history of data visualization by exploring Data by Design: An Interactive History of Data Visualization, 1789-1900 (2024 public beta created by Lauren Klein, Tanvi Sharma, Jay Varner, Shiyao Li, Margy Adams, Nicholas Yang, Dan Jutan, Jianing Fu, Anna Mola, Zhou Fang, Yang Li, and Silas Munro).

  • ClioVis - a visualization tool that allows you to make networked connections across time and space
  • DataBasic - a suite of easy-to-use web tools for beginners that introduce concepts of working with data to help you learn how to find great stories to tell
  • Datawrapper - tool for creating charts, maps, and tables; free version available
  • D3js - a JavaScript library for manipulating documents based on data
  • Exhibit - create, narrate, and share exhibits of digital collections. Use their hosting option or you can self-host. IIIF compatible. Learn more about the features.
  • Mapbox - A low-code template for map-based interactive storytelling
  • Neatline - a plugin for Omeka that allows for spatial and temporal visualization
  • Onodo - a free tool for creating network visualizations. Onodo sunsetted in June 2024.
  • OpenRefine - free data cleaning tool to help normalize (standardize) your data before you try to visualize it
  • Palladio - browser-based visualization tool for complex historical data; see also Palladio Web Elements repository for publishing Palladio visualizations on other websites
  • Raw - browser-based visualization framework for complex data
  • ArcGIS StoryMaps - narrative-driven map templates; SDSU faculty, staff, and students have free institutional access (log in with your SDSUid and navigate to the StoryMaps app). Learn more about ArcGIS StoryMaps. Need to georectify a map? Try Map Warper.
  • Storiiies - image-centered digital storyteliing. Take people on a journey round your images. Pan and zoom across your image and annotate points of interest. Sites can be self-hosted or use the free hosting option.
  • StoryMapJS - allows you to create media-rich, interactive, web-based maps without needing to knowing GIS (requires Google account)
  • Tableau and Tableau for Students - powerful data visualization tool
  • TimelineJS - allows you to create media-rich, interactive, web-based timelines
  • TimeMapper - create timelines and maps from a Google spreadsheet
  • Social Explorer - spatial visualization tool
  • Suave - online platform for visual exploratory analysis of surveys and image collections

 

Also, consider issues of accessibility when working on visualizations, including color blindness, mobility, visual and hearing. There are numerous tools, such as Color Brewer, that can help you pick accessible color combinations for your visualizations, such as maps.

 

Looking for something not on this list? Check out this set of data visualization tools (not all are free).

Digital Exhibits allow for online curation, publication, and exhibition of information, artifacts, and works, making these items accessible to more people while preserving the original object. Additionally, the practice can allow for repatriation of items while still providing virtual access (when appropriate). Omeka, for example, is a platform that allows you to create digital collections and exhibits for the public. There are many other digital exhibit platforms, but most require server space, whether hosted by your institution or by a third party.

  • Clio - free tool for creating virtual historical tours. New entries are being added daily by universities, libraries, museums, and historical societies. Supports images, oral histories, videos, audio, and links to sources and sites.
  • CollectionBuilder - an open source framework for creating digital collection and exhibit websites that are driven by metadata and powered by modern static web technology.
  • Exhibit - create, narrate, and share exhibits of digital collections. Use their hosting option or you can self-host. IIIF compatible. Learn more about the features.
  • Historypin - digital collection and mapping platform designed for cultural heritage organizations to engage in community-based storytelling
  • Omeka - exhibit platform for digital collections. Learn more about how to access/use Omeka at SDSU Library.
  • Storiiies - image-centered digital storyteliing. Take people on a journey round your images. Pan and zoom across your image and annotate points of interest. Sites can be self-hosted or use the free hosting option.
  • Suave - online platform for visual exploratory analysis of surveys and image collections

There are many other digital exhibit platforms, but most require server space, whether hosted by your institution or by a third party. Free website builders/content management systems, such as WordPress or WiX, could potentially be set up for digital exhibits.

Slightly unrelated, but for those doing archival research, the Center for History and New Media at George Mason University recently released Tropy, a free tool that helps you organize, describe, and annotate archival research (particularly the photos you take of documents).

Electronic Literature and Storytelling is a genre of literature where the works are created to be experienced exclusively on digital devices such as computers and smartphones. Twine, as an example, is an open-source tool that allows users to make interactive fiction without previous coding experience. The Electronic Literature Organization maintains a directory of e-lit to inspire you. And check out this blog post, "Introduction to the World of E-Lit," by Brent Ameneyro, 2021-2022 DH E-Lit Programs Assistant.

  • Cheap Bots, Done Quick - easy-to-use site for creating Twitterbots
  • Ink - language and editor for creating interactive fiction. Can be ported into Unity or run through a web browser
  • Mark C Marino Works & Tools - various works of electronic literature and the tools used to make them
  • Scalar - authoring and publishing platform that’s designed to make it easy for authors to write long-form, born-digital scholarship online. Scalar enables users to assemble media from multiple sources and juxtapose them with their own writing in a variety of ways, with minimal technical expertise required. Explore the DH Center's Scalar tutorials, created by Andrea Berreondo, Alexandria (“Allie”) Henderson, and Mik Knight under the direction of Romain Delaville (Fall 2022).
  • Stepworks - create one word digital poetry
  • Twine - open-source tool for telling interactive, nonlinear stories. Learn more at the DH@SDSU's Teaching During Quarantine website, and see these tutorials created by Cathy Qiu, DH Center Assistant, in Spring 2021. The Programming Historian offers Twine tutorials, as well.

There are several environments where you can code your own stories, including Google's Colaboratory (for coding in Python) and Jupyter Notebooks (an open-source web application that allows you to create and share documents that contain live code, equations, visualizations and narrative text).

Ethical design is design that prioritizes human values. Most people do not design with the intention to cause harm to others but sometimes that is the unforeseen result. Design can bring harm to individuals and groups of people. Ethical design brings attention to this, and ethical design tools, such as the EthicalOS, aim to help users mitigate (unintended) harm with design. 

  • Design for Diversity Learning Toolkit - a collection of learning resources, gathered between 2016 and 2018, that can be used in a classroom, workplace, or volunteer organization to help cultural heritage practitioners advocate for and create more inclusive information systems
  • EthicalOS - toolkit to help inform your design process today and manage risks around existing technologies in the future
  • How to Begin Designing for Diversity - created by the Creative Independent, this is a guide to get you started in building equitable products, services, and content
  • Minimal Computing - computing done under some set of significant constraints of hardware, software, education, network capacity, power, or other factors; an approach that balances choice and necessity, gains and costs, thereby relating to issues of aesthetics, culture, environment, global relationships of power and knowledge production, and other economic, infrastructural and material conditions
  • Value Sensitive Design - a design process for software and projects that seeks to anticipate unintended consequences of the things we make; seeks to provide theory and method to account for human values in a principled and systematic manner throughout the design process

A website is a collection of resources, such as webpages and media content. All websites “live” (i.e. are hosted) on a server. Hosting is a service that makes websites accessible to others--it stores the information of the website and allows people to recall it via a device and internet connection. CMS stands for Content Management System. It’s a tool that allows users to create and modify digital content and the collection of content without necessarily knowing how to code. Whereas in the past websites were manually coded line by line, a CMS allows you to create and publish websites without having to worry about the code. WordPress, for example, is one of the leading free website creation tools (though hosting a Wordpress site may not be free).

  • Drupal - powerful CMS that is highly customizable; requires hosting service but you can try a free trial
  • GitHub Pages - free hosting through the GitHub Repository, one site per GitHub account and organization, and unlimited project sites; best for static websites
  • Google Sites - easy-to-use wiki-styled website builder with multiple templates and easy Google app integration; supports real-time collaboration; requires Google sign-on. SDSU users can log into Sites through their SDSUid.
  • Humanities Commons - free online network for humanities scholars; in addition to their open access scholarship and repository, you can create an account and build your own WordPress websites.
  • KNIT - a digital commons (built with Commons in a Box) for UC San Diego, San Diego State University, and the San Diego Community College District! Log in with your SDSUid and get started building WordPress websites, joining groups, and networking with other campus members
  • Murkutu - content management system designed for community-driven digital cultural heritage preservation whereby communities control levels of access using Traditional Knowledge (TK) Labels and cultural protocols
  • Reclaim Hosting - third-party hosting that provides institutions and educators with an easy way to offer their students domains and web hosting that they own and control; supports easy install of WordPress, Omeka, and Drupal
  • Scalar - authoring and publishing platform that’s designed to make it easy for authors to write long-form, born-digital scholarship online. Scalar enables users to assemble media from multiple sources and juxtapose them with their own writing in a variety of ways, with minimal technical expertise required. Explore the DH Center's Scalar tutorials, created by Andrea Berreondo, Alexandria (“Allie”) Henderson, and Mik Knight under the direction of Romain Delaville (Fall 2022)
  • SDSU Library Web Hosting - SDSU faculty and staff may request web hosting through the SDSU Library. Users must register a unique domain name and comply with security and accessibility standards. Web hosting enables you to access the cPanel, the web hosting Control Panel. Here you can load files (via FTP protocols) or install a content management system such as WordPress. You must have VPN to access your cPanel or anything hosted in your space.
  • WordPress - CMS, blogging platform, and website generator that's easy to use (34% of all websites are built on WordPress); offers free website hosting (limited to 1 site, but there are paid plans as well) or easy install on most (if not all) third-party hosting services (such as Reclaim); open source code can also be downloaded and installed on your own server
  • WiX - free website builder with many templates; you can create as many sites as you like

 

Wikis are another approach to website creation. There are several wiki platforms available, including MediaWiki and PBworks.

Network Analysis is a practice of visualizing complex networks. It can be used to visualize networks of people, behaviors, ideas, and more. For example, Onodo allows users to map, visualize, analyze, and communicate complex networks and data.

  • Cytoscape - open source software platform for visualizing complex networks and integrating these with any type of attribute data
  • DataBasic - a suite of easy-to-use web tools for beginners that introduce concepts of working with data to help you learn how to find great stories to tell
  • Gephi - visualization and exploration software for all kinds of graphs and networks
  • Graph Commons -  supports the creation of interactive maps that visualize complex relations (free account available for public data projects)
  • NodeXL - easy to explore, analyze and visualize network graphs in Microsoft Office Excel; free basic version available
  • Onodo - easy-to-use, free network visualization builder. See this tutorial (video and slides), created by Fabrizio Lacarra Ramirez, DH Center Student Assistant, Spring 2021. N.B.: Onodo will not be available after June 30, 2024.
  • Palladio - visualizes relationships as maps, graphs, lists, or galleries

Podcasting is an increasingly popular form of publicly-engaged digital scholarship. Podcasts can take many forms and foci, including academic, creative, current issues (news and politics), and humor, to name a few. The DH Center in SDSU Library is home to two DIY Podcasting Studios that can be booked by all SDSU faculty, staff, and students. We also offer a set of resources to get you started, including recommended tools for recording and editing audio, free audio sites, and best practices. 

  • DH Center Podcasting Resources & Tutorials: includes instructional slide decks for recording and editing audio, recommended tools, sites for free audio downloads, and best practices for creating your own podcast.

 

Resources for Getting Started

 

Recording and Editing Tools

  • Audacity: Free, open source, cross-platform audio software (a DH Center favorite!)
  • Adobe Audition: free for all SDSU users (requires SDSUid to access)
  • Hindenburg: audio editor for podcasts, e-books, and digital storytelling; not free but educational licenses are available
  • Zencastr: Cloud-based podcasting platform ideal for recording multiple voices in different locations; video podcasting available. Free account available, with additional features during the COVID-19 pandemic (a DH Center favorite!).
  • Cleanfeed: a collaboration tool for live audio and recording, in your browser. Free account available
  • Squadcast: browser-based platform for recording podcasts; not free
  • Zoom: allows you to record separate audio files for each participant (ideal for editing in a multitrack project): Settings > Recording. This works for local recordings saved to your computer (configure the desktop client settings) and cloud recordings (configure through your Zoom web interface). Bonus: turn on live transcription to get a messy transcript of the recording session. Audio files will be saved as .m4a, which you may need to convert to .wav or .mp3 before editing
  • Chromebooks generally don't support standalone audio software, but rather rely on browser-based tools (no install required): Spotify: Anchor and Soundtrap (30 day free trial); Veed.io (for videos but can be adapted for audio; free account limited to 10 minute recordings); TwistedWave - online recording/audio site; basic editing features, plus many others.
  • Online Audio Converter - free browser-based tool for converting audio files (e.g. .m4a to .wav)
  • Convertio - free browser-based tool for converting audio files (e.g. .m4a to .wav)

 

Details about re-using/re-mixing free, public domain music and sound effects are included at the bottom of this page.

 

Resources for creating podcast cover art:

 

Resources for hosting and sharing podcasts:

A repository is a virtual space for storing, preserving, and providing access to digital objects. SDSU Library’s institutional repository, SDSUnbound, hosts course syllabi, theses, and several digital archival collections.

  • GitHub - originally designed to share and collaborate on open source software, many DHers use it as a repository, where they can host files, presentations, media, and other shareable digital assets; branching allows for easy collaboration and sharing
  • Open Science Framework - project management, collaboration tool, and repository originally created for open science, the platform can host all aspects of scholarship, from data to publication; DH folks have begun to explore how they could use OSF for their own repository needs

 

Related to preservation of DH work is the question of sustainability. Explore The Endings Project, a five-year project to create tools, principles, policies and recommendations for digital scholarship practitioners to create accessible, stable, long-lasting resources in the humanities.

Many DHers are self-taught in the spirit of D.I.Y. Here is a list of tools that can help you learn on your own. While formal routes of education can be cost prohibitive, learning does not need to be. For example, Codecadamy guides people in learning to code for little to no fee.

  • Codecademy - self-paced learning for how to code, from building a website to analyzing data
  • Coding for Beginners - beginner-friendly tutorials to build your skills and launch your next project, created by Digital Ocean
  • Coding and Design for Virtual Reality - provides a list of popular VR coding languages with links to additional resources
  • Getting Started with Data, Tools, and Platforms - open Zotero library (HILT 2017 workshop)
  • Lynda.com - subscription-based courses on a wide range of tools and topics
  • Teaching Yourself to Code in DH - (Scott Weingart) a crowdsourced spreadsheet of programming & methodological textbooks for humanists
  • Technical Resources - aggregation of technical resources for those who are new to coding and would like to learn the basic concepts; topics include: programming languages and learning resources, web development, and server management
  • Programming Historian - novice-friendly, peer-reviewed tutorials that help humanists learn a wide range of digital tools, techniques, and workflows to facilitate research and teaching
  • Python Tutorials for Digital Humanities - YouTube videos specifically created for those with no prior experience coding; videos address common problems humanists face in their research and the Python solutions to those problems
  • w3schools - free online tutorials for HTML, CSS, JavaScript, Server Side (SQL, PHP, ASP, Node.js, Raspberry Pi), Programming (Python, Java, C++), Web Building, XML

Text Analysis is the practice of using machines to analyze large collections of text. The result can be visual, as with the tool Voyant, and allow for new understandings of content. Text markup tools let readers annotate digital texts and some, such as Hypothesis, allow for social markup--a group of people annotating text together. Learn more about computational text analysis with the Data-Sitters Club.

  • Annotation Studio - suite of collaborative web-based annotation tools currently under development at MIT; allows you to read, share, annotate, share, and compose
  • Constellate - text analytics platform that supports teaching and learning text analytics, building datasets from across multiple content sources, and visualizing and analyzing datasets, pulling from JSTOR's digital collections, including Chronicling America, Documenting the American South, the South Asia Open Archives and Independent Voices from Reveal Digital.  
  • Distant Reader - a tool for reading and understanding large amounts of text. The Reader locally harvests/caches content, transforms the content into plain text, performs sets of natural language processing & text mining against the text, saves the results in a number of formats, reduces the whole to a cross-platform database file, queries the database thus summarizing the collection, zips the results of the entire process into a single file, and makes the file available for further investigation--"reading"
  • Gale Digital Scholar Lab - a set of analysis tools that allows you to build work sets among Gale's digital collections (or upload your own), perform analysis (using various Natural Language Processing and text analysis methods), and visualize results; the tool is not free but if you are interested in using it (especially in the classroom), please email librarydh@sdsu.edu
  • Google Ngram Viewer - allows you to track and visualize the usage of words over time in Google's digitized book corpus (limited to Google's collection
  • HathiTrust Bookworm - allows you to search for trends in millions of volumes of digitized books from the HathiTrust Digital Library; one of many analysis tools available through the HathiTrust Research Center (HTRC). Additional HTRC tools include: Recommended worksets for HTRC Analytics, HTRC Workset Toolkit for use in the HTRC Data Capsule, and HathiTrust Text Prep python library.
  • Hypothesis - collaborative annotation tool for the web; enables sentence-level note taking or critique on top of websites, such as news, blogs, scientific articles, books, terms of service, ballot initiatives, legislation and more
  • Lexos - web-based tool to help you explore your favorite corpus of digitized texts
  • Mallet - a Java-based package for statistical natural language processing, document classification, clustering, topic modeling, information extraction, and other machine learning applications to text
  • Natural Language Toolkit (NLKT) - a leading platform for building Python programs to work with human language data. It provides easy-to-use interfaces to over 50 corpora and lexical resources, along with a suite of text processing libraries for classification, tokenization, stemming, tagging, parsing, and semantic reasoning, wrappers for industrial-strength NLP libraries, and an active discussion forum
  • Recogito - an online platform for collaborative document annotation; supports: uploading texts and images, creating annotations, identifying and mapping places in your documents, exporting data in order to re-use it elsewhere, and collaboration
  • Voyant - web-based reading and analysis environment for digital texts. Additional resources are available, including tutorials created by DH Center Student Assistants Keonna Kinshasa (Summer 2020) and Fabrizio Lacarra Ramirez (Summer/Fall 2021). See also this open textbook, Dialogica: Thinking-Through Voyant.

 

Cookbooks and Open Textbooks for Text Analysis in Python, R and other Languages:

  • A Humanist's Cookbook for Natural Language Processing in Python - a series of notebooks, a collection of Python 3 recipes for common problems and issues associated with preparing data for text analysis and natural language processing. The target audience is students or intermediate programmers who have begun to learn their way around Python but who need a little help pulling the pieces together to get something done
  • Introduction to Cultural Analytics & Python - offers an introduction to the programming language Python that is specifically designed for people interested in the humanities and social sciences.
  • Named Entity Recognition Textbook - an in-progress series of notebooks for named entity recognition (NER), a task of natural language processing. The purpose of NER is to extract structured data from unstructured texts, namely specific entities, such as people, places, dates, etc.
  • Supervised Machine Learning for Text Analysis in R - an open access textbook that "focuses on supervised or predictive modeling for text, using text data to make predictions about the world around us. We use the tidymodels framework for modeling, a consistent and flexible collection of R packages developed to encourage good statistical practice."

 

There are many transcription tools available as well, including:

  • From the Page - free software that allows volunteers to transcribe handwritten documents on-line. It's easy to index and annotate subjects within a text using a simple, wiki-like mark-up. Users can discuss difficult writing or obscure words within a page to refine their transcription. The resulting text is hosted on the web, making documents easy to read and search.
  • Juxta Commons (NINES) - Juxta is an open-source tool for comparing and collating multiple witnesses to a single textual work. Originally designed to aid scholars and editors examine the history of a text from manuscript to print versions, Juxta offers a number of possibilities for humanities computing and textual scholarship. As a standalone desktop application, Juxta allows users to complete many of the necessary operations of textual criticism on digital texts (TXT and XML). 
  • Juxta Editions - professional editing suite for the creation of digital scholarly editions. It provides assistance during the entire process of preparing a digital edition, from transcribing texts to editing and annotating them, to publishing online. 
  • Scripto plugin for Omeka - allows you to crowdsource the transcription of your Omeka Classic content (see the Digital Exhibits tab for more info about Omeka).
  • Transkribus - Manage, segment, and transcribe handwritten text in any language and with any character set. You can even load your own virtual keyboard! Export your documents in several formats such as TEI, RTF, PDF, XML. See also Transkribus Lite

 

Interested in performing textual analysis of social media sites? Check these out and make sure to consider the ethics of scraping/using social media data:

  • DocNow - a tool and a community developed around supporting the ethical collection, use, and preservation of social media content.
  • Netlytic - a cloud-based text and social networks analyzer that can automatically summarize and discover communication networks from publicly available social media posts. It uses public APIs to collect posts from Twitter and YouTube. It also supports the analysis of your own datasets.
  • Scrapy - An open source and collaborative framework for extracting the data you need from websites. In a fast, simple, yet extensible way.
  • Sysomos - tool for social media analysis
  • Twitter Archiving Google Sheet (TAGS) - a free Google Sheet template which lets you setup and run automated collection of search results from Twitter.
  • TweetSets - Twitter datasets for research and archiving. Allows you to create your own Twitter dataset from existing datasets.

 

Want to learn how to create your own font? Check out this tutorial for using FontForge, created by DH Center Assistant Cathy Qiu, Spring 2021.

As you learn more about Digital Humanities and DH projects, you may want to expand your toolset. These directories provide a list of tools and resources.

Translation is the process of taking content and information written in one language and making it accessible in another language. At its core, DH is committed to global diversity. One way to uphold this value is through the translation of projects. Making work and conversations more globally accessible encourages collaboration and community. 

  • GO:DH Translation Toolkit - set of recommendations for translation practices to be used by researchers, librarians or cultural heritage workers
  • Multilingual DH - a loosely-organized international network of scholars using digital humanities tools and methods on languages other than English. Their website includes a list of resources for engaging in natural language processing in many languages.

DH Collaboration: Giving and Receiving Credit

Digital Humanities work is deeply collaborative, so it's important to "give credit where credit is due." This includes being transparent about roles, responsibilities, distribution of labor, and specific work performed.

For scholars concerned about how to "count" their DH work for tenure and promotion, this list of guidelines and best practices for evaluating digital humanities/digital scholarship can help:

Several leading professional societies regularly incorporate digital project reviews in their journals. There are also some dedicated venues for peer review of digital projects, including:

Public Domain Content for Reuse

Need digital content for a project? Make sure the content you re-mix/re-use is in the public domain. (Learn more about copyright and fair use.) Not sure where to look? Check out these sources and always remember to double-check the specific use license for any item you want to use.

Images

You can also conduct an image search in Google, Duck Duck Go, or similar and constrain your results to public domain/creative commons licenses: Google Advanced Image Search: Tools > Usage Rights > Creative Commons licenses.

Audio

And explore this list of top royalty-free and paid sources for podcast music