DNG options and problems in ACR/Bridge CS3.

JC
Posted By
Joseph Chamberlain
Jun 14, 2007
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359
Replies
3
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Closed
Dear members:

I recently digitized a large number of slides with a Nikon scanner and saved the images as TIFF files (only options were TIFF or NEF. NEF created by Nikon scanners is not supported by ACR so the logical choice was TIFF).

Since my workflow requires the addition of metadata to these images I decided that DNG would be the ideal file format as the metadata can be incorporated in the image without the need for a second XMP sidecar file that can be easily lost or misplaced.

The tools I have found that can convert TIFF images to DNG are Adobe’s Lightroom and ACR hosted by Bridge CS3. Lightroom offers a simpler and more straightforward conversion with not options offered. ACR hosted by Bridge CS3 offers some options – compression and linear image. These options are covered under the help files when the conversion to DNG is made from a RAW file. However, the help files don’t provide enough details about the conversion from TIFF (and JPEG also) to DNG.

The questions I have are:

1. When converting TIFF to DNG is it possible to keep the image intact so that it can be later extracted much in the same fashion that a RAW file can be preserved should it become necessary to recover it later ? In this case, what application could be used in the future to extract the original TIFF image from the DNG file ?

2. The option to compress the original image as ACR hosted by Bridge CS3 makes the conversion can save some disk space but will it affect how other applications open these DNG files ? Will other applications continue to open these files and what impact will it have on performace (time necessary to decompress and open image) ?

3. What does the linear option do the TIFF or JPEG file as the image is being converted to DNG ?

4. I noticed that Apple’s support for DNG is erratic and unreliable. I have opened some DNG files with Preview but the ones I have created with both Lightroom and ACR hosted by Bridge CS3 are not recognized by it. Why is there a distinction in the way Apple’s Preview treats these DNG files ? Is there a difference between DNGs created from RAW files and DNG files created from TIFF or JPEG images ?

Thank you in advance for your help,

Joseph Chamberlain

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MR
Mike Russell
Jun 14, 2007
"Joseph Chamberlain, D.D.S." wrote in message
Dear members:

I recently digitized a large number of slides with a Nikon scanner and saved
the images as TIFF files (only options were TIFF or NEF. NEF created by Nikon scanners is not supported by ACR so the logical choice was TIFF).
Since my workflow requires the addition of metadata to these images I decided that DNG would be the ideal file format as the metadata can be incorporated in the image without the need for a second XMP sidecar file that can be easily lost or misplaced.

I recommend that you stay with your TIFF file format. Although DNG is a promising digital negative standard, it is not designed for generalized image storage. For example, you cannot edit a DNG file in Photoshop.

Bridge and other programs will write metadata to TIFF files. If you want to use Adobe Camera Raw v4, it will also support TIFF.

Mike Russell – www.curvemeister.com
J
Joe
Jun 14, 2007
"Joseph Chamberlain, D.D.S." wrote:

<snip>
Thank you in advance for your help,

Joseph Chamberlain

I believe I read both your question about DNG and someone already responsed to your DNG question.
JM
John McWilliams
Jun 14, 2007
Mike Russell wrote:
"Joseph Chamberlain, D.D.S." wrote in message
Dear members:

I recently digitized a large number of slides with a Nikon scanner and saved
the images as TIFF files (only options were TIFF or NEF. NEF created by Nikon scanners is not supported by ACR so the logical choice was TIFF).
Since my workflow requires the addition of metadata to these images I decided that DNG would be the ideal file format as the metadata can be incorporated in the image without the need for a second XMP sidecar file that can be easily lost or misplaced.

I recommend that you stay with your TIFF file format. Although DNG is a promising digital negative standard, it is not designed for generalized image storage. For example, you cannot edit a DNG file in Photoshop.
Bridge and other programs will write metadata to TIFF files. If you want to use Adobe Camera Raw v4, it will also support TIFF.

DNG is editable rather extensively from a macro point of view in PS Bridge, and ACR 4.1 has some new controls. Lightroom also does this, but it’s ca. $300.


john mcwilliams

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