What is archival or preservation quality? And what is the recommended capture resolution/file size for archived material?
First, Archival and preservation are both just words….they are not standards and do not have any exact values. second, what is archival or preservation for one project or image will not necessarily be so for another. This totally depends on what the intended use of the image is. It would be the intention to archive or preserve all the quality that is required to present the image to the highest quality chosen as appropriate for delivery. This of course sounds like a chicken or egg situation and for any project, the first question is to decide what level of quality is appropriate for that image. There are very many ways of going about making this decision…. You could decide on a largest output printed size required for images, for instance A3 quality print would mean 50Mb or so, A4print would mean about 24Mb. If like the National Gallery you wish to create life size copies, then you would need many hundred Mb for each image. You could decide on how much visual information is kept wi