These DNGs have been opened before in ACR and/or LR.Īccording to Ed Hamrick, the author and maintainer of Vuescan, once opened in ACR/LR a tag is written into the DNG, c716 for ACR and c717 for LR, alongside a low res preview (a 1:1 preview is in the LR database). This is causing Vuescan to only see the low res preview at 300dpi (my ACR workflow setting). Ed is not able to give a solution and regards these DNG's as being manipulated. Maybe Vuescans implementation of DNG is defying the purpose of DNG being an archival file format, but that is not solving my problem right now. Is there a way to strip off all the tags and preview(s) written into the DNG to return the Vuescan DNG into its pristine state before opening into ACR/LR, because these untouched DNG's properly show up as 4000dpi files in Vuescan.

My recollection from archiving scanned Kodachrome slides using VueScan, is that VS uses the DNG file to store data about the scanner's IR channel (used for dust/scratch removal, if so equipped). Perhaps it stores other scanner data as well, but the IR channel is what I was interested in at the time. Thus one can later open the DNG in VS then 'rescan' the image from 'the file' and reapply dust/scratch removal at a different intensity. I think VS also has an option to save a TIF at the same time, though the current IR settings are burned into the TIF.ĭuring my archiving I saved a DNG for subsequent rescans in VS (if needed) as well as a TIF to use with other apps (usually Capture NX2, which doesn't use DNGs). If one finds his scan to be too soft once he loads the TIF into his image editor, he can rescan the image from the DNG, apply a weaker dust/scratch removal intensity, and then create a new TIF.

I really can't say if the VS DNG is meant to be used with other apps as my only use for them is with VS. I would say vuescan's DNG is a valid archival format for VS, but have no idea if it would be considered a 'true archival format' in the sense that it's compatible with any app that can open DNGs. Sorry I can't offer a way for the OP to return his VS-generated files to their original state.ĭoes that include what Adobe ACR/LR apparently writes to the file upon merely opening it? You seem to jump to the defence of Adobe very quickly. How sure are you that they are not writing undocumented Tag data? Really, how is a third party developer who is reading the specs supposed to know which tags are altered for no apparent reason ( opening a file, for Pete's sake). Apparently he/she needs to assume the worst. So what is it that you base that on?Īny solutions on offer to the OP's plight? I'm not saying that Ed Hamrick is following all the specs (maybe he is, maybe he isn't), but you seem to be suggesting that he isn't.

Vuescan 9.0.21