Hi Stefano, I bet that you would be able to use the WriteMetadata Method for an ENVI Raster. Here is a link to the documentation: http://www.exelisvis.com/docs/enviras... You can use ENVIRasterMetadata::UpdateItem to update a metadata item in the header or ENVIRasterMetadata::AddItem to add a new item to the metadata. The first link shows a good example of how this is used and you could probably extend this to a batch process by opening the files, updating the metadata, and then saving the header information.

That looks like what I need, thanks for you suggestions!