Previews are static formats, available for File Types. 

• The standard Windows server fonts are installed on our rendering server and will be applied and rendered to document previews. Any other fonts will be substituted.
• You see a file format icon when Fotoware Alto couldn’t render a preview, e.g., Indd for InDesign files.
• The original file is also available; accessing (downloading) it can be restricted by Content Permissions. 

You cannot restrict Access/Download of previews, but you can add a watermark to the Preview, which is then also applied to other Formats and Thumbnails derived from the Preview. Check for formats and thumbnails to ensure the Watermark is applied everywhere when the rendering source is the Preview format.

Fotoware Alto generates the following previews for supported file formats.

Dynamic Formats can be defined for images only and are rendered on demand for the selected Content Item in Fotoware Alto; they are not saved to storage but are cached for the configured retention time. Dynamic formats may be Hero Images, Social Media Images, or Campaign Specials.

The benefits of dynamic rendering

• Those are customizable by the customer during operation (setup via API)
• Dynamic formats are cached (via the retention time configuration), so the downloader does not have to wait for frequently accessed content. 
• Fotoware Alto does not store them, saving on the monthly storage subscription fee. 

The drawback of dynamic rendering

• Downloading multiple dynamic formats of the same Content Item is possible. 
• Rendering on request (lazy) may take some time until Fotoware Alto generates the output. Fotoware Alto will notify you when the ready-to-download file is available.
  
  You can continue working in Fotoware Alto while your download is being prepared. 
• Only available to produce images (rasterized files). 
• Costs performance of rendering microservice.

Static formats are created during customer creation, predefined, and rendered for every Content Item in Fotoware Alto, and saved to storage. The benefits of static formats

• No waiting times for downloading them. Fotoware Alto creates the format after import, and every user can then download it directly.
• You can have static formats created for all file types (based on rendering support). 
  The drawback of static formats
• Costs storage, as all formats are rendered and saved there.

Example of a Rendering Chain for static formats, where Fotoware Alto, e.g., creates the thumbnails of an image based on the preview format. The main benefit is that, e.g., watermarks of the Preview are automatically available on all thumbnails, except if you remove the watermark with a crop action.

Additional source considerations for choosing the source format: 

• The source must be of sufficient quality to produce the desired format; e.g., you should not create a high-res print format from a small thumbnail. 
• To save resources, the source should match the output in size and resolution, but be a bit larger. An original file may be huge, and producing a small thumbnail would waste rendering resources and take time. 
• For dynamic formats, a setting "view for all" is available. This setting will enable you to access the dynamic format without giving access to the source. Therefore, dynamic outputs rendered based on the source Original do not require “AccessOriginal permission”. 
• The source can be temporary and unavailable for download or not visible in Fotoware Alto. 

• Fotoware Alto reserves the right to change specifications for static formats at any time, as announced in the Fotoware Alto release notes.
• Fotoware Alto currently does not write XMP or EXIF metadata into previews.
• You can repair formats via the API for those that did not render correctly. Rendering failures appear when the rendering service is unavailable or when rendering component updates are made. An automatic job runs every hour to re-render failed items a few times. Afterward, they will stay failed.
• Document rendering requires Fotoware Alto to know the font. Unknown fonts are not rendered correctly, leading to incorrect previews. The Preview's watermarks are automatically applied to all thumbnails; unless you remove them, your download is being prepared. You can change the font in the document to fix the previews.