Loss of revenue

 
Images like this is in the public domain, since the federal policy in the US is that the public shouldn't have to pay twice for the same material.

Large parts of the collections that exists in galleries, libraries, archives and museums have been paid for with money from the public. Charging members of the public who want access to "their" material can be seen as a tautology. Especially when the material is in the public domain.

Of course, there are a few works that sell posters and postcards, and we don't have any intention of blocking streams of revenue, but the majority of the cultural heritage will never bring in any money. By decreasing the focus on sales, the staff can digitize more material, which then will be accessible to more inviduals. Some cultural heritage institutions have even stopped selling material.

There have been some research into revenue from sales in cultural institutions. Oftentimes the revenues are minimal (compared to the budget as a whole) and are overshadowed by the cost of the staff for the sales. On the other hand, institutions that publish a lot on the internet, have an easier time finding new audiences, including physical visitors, and even an increase in sales since the material works as a shop window. How else can the public know that is in the institution?

Can you refrain from charging from the material you are producing?

In the US, everything that is produced by federal employees (such as at NASA), is automatically placed into the public domain. This has disseminated this material more than equally good material from other countries which has been locked in by exclusive contracts. A simple way to make it easier for the images to be disseminated is to use the licenses of Creative Commons. If you use Create Commons licenses, use the ones that allow for commercial reuse, so that they may be uploaded to Wikimedia Commons.