View Full Version : Vuescan and size of DNG file

6-Mar-2013, 02:38
I scanned a photograph using vuescan pro. and a Epson 3490 Perfection scanner. I set vuescan to output a raw compatible file with DNG extension.
The file created had a physical size on the hard drive of 144 Mega-bytes. When opened in camera-RAW 7.3 and simply saved without compression it became 74 Mega-bytes. I open both files in photoshop cs6 and they both read exactly the same in all respects including size on disk i.e. Doc:144/144 all dimensions and resolution are the same. Is file compression taking place silently without my knowledge when I saved from Camera RAW?
If the file's contents expand to the same, then is it possible to get vuescan to save the files in the smaller size?

6-Mar-2013, 05:52
I've given up on scanning in raw with VueScan... I know all the benefits of raw with digital cameras but with vuescan, it creates more problems than it solves. Also the DNG feature is just there for compatibility with software that might now allow TIFF files.

Also these scanner files aren't mosaics like what you get with digital camera sensors... I prefer saving as non-raw TIFF instead of raw TIFFs/DNGs because the curves are more like what I want at the end of the day. Hope someone here can point out some exceptions... would be good to know if there are any.

Larry Gebhardt
6-Mar-2013, 06:16
It may be saving extra channels, such as the IR, in the DNG file. I do not know this for sure. I doubt Camera Raw would be able to do the dust removal with this channel, so if it's there I imagine it's ignored.

6-Mar-2013, 07:56
Thank you both (genotypewriter, and Larry) for your good answers. I'm taking that advise and just save as jpeg and tiff from now on. I'm going to process the files that I did that way in some sort of batch run think maybe Adobe lightroom may have an option just to re-save each file, to nearly halve the disk space storage requirement.

Light Guru
6-Mar-2013, 08:14
the DNG feature is just there for compatibility with software that might now allow TIFF files.

What software would be compatible with DNG files but not TIFF files. TIFF files are MUCH MUCH MUCH MUCH more common then DNG files.

There are already several threads on the forum about viewscan raw files so I would recommend always doing a search before posting.

23-Mar-2013, 11:14
Why not just save it as a TIFF? DNG created more problems than it solves. Oh wait, DNG is a solution to a non existent problem.

24-Mar-2013, 03:37
Oh wait, DNG files are actually TIFF files with a different extension and a couple extra tags defined.