This article is based on a function supported since neoStampa Delta.
I cannot see transparency in TIFF files when opened in neoStampa in the DTG document. This means that the background color of the media is not visible in my print file and the background of my print file is white.
When saving a tiff file in Photoshop, it shows a dialog where it is needed to check the box (Save Transparency). Open the file, save it again with a different name, and make sure in the save tiff options that the transparency is selected. If you prefer to, you can save files in .png which will always save the transparency without any interaction.
Open the new saved file in neoStampa DTG mode and you should see the media color visible in the print file.
Top image: Has transparency / Low image: No transparency