8 bit DNG files?

[Deliberate1]

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Friends, as I was reviewing some images I down loaded today, I noticed that they were identified as 8 bit files. It came as a surprise as I am shoot DNG, which I always assumed  created 16 bit files as default. I checked the camera and confirmed that I am shooting in compressed mode and wondered if that might have something to do with it. Naturally, as I shoot with this camera to get the best possible files,  it is a bit disheartening to be dealing with 8 bit vs 16 bit. Typically, my workflow starts in LR for tonal and color work. And then I finish in PS CS5 for more isolated work. If I open the file in PS and convert the 8 bit file to 16 bit mode will that get me the tonal range I want. Now that I think about it, should that be done in LR (if possible) as that is where I am doing that kind of adjustment.

Appreciate the help

Thanks,

David

[Jeff S]

Have you checked your external editing preferences to be sure you're using 16 bit?

 

Jeff

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[Deliberate1]

Jeff, that 

 

Have you checked your external editing preferences to be sure you're using 16 bit?

Jeff

Jeff, thanks for yours. By that do you mean settings in LR or PS?  I discovered the issue wnen I opened an image in PS and then went to image mode which Indicated that the file was in 8 bit. I will do an experiment, but have a suspicion that compressed files are read as 8 bit until changed to 16 bit manually in PS.

Cheers,

D

[Jeff S]

Maybe this will help...

 

http://blogs.adobe.com/richardcurtis/2015/03/20/creativefriday-lightroom-and-photoshop-raw-workflow-colour-space-and-bit-depth-tips/

 

Jeff

[jip]

The file is 16 bit but if your editing software is set to work in 8bit mode you instantly throw away all the other data upon opening the file  

[jaapv]

What editing softwware do you use?.

DNG files have no bit value, that is created when developing the file. However, the sensor has written an 16 bit file into the DNG which must be extracted.

If you are using Photoshop, you will see a blue text under the image in Camera Raw, specifying the 8, 16 or 32 bits and the colour space. Click it, and you can choose the parameters. Set it to 16 bits and Adobe RGB. The progam will remember the setting.

 

If you are planning very heavy postprocessing it is wise to use a 32 bits file, as that will preserve data and avoid posterizing. I normally convert to 32 bits anyway.

 

Look at it this way:

 

The bits of your postprocessing program can be imagined as a row of buckets, 8, 16 or 32 of them

Now the DNG will pour the 16 bits of your data into these buckets. Obviously, with only 8 buckets you will end up with some data lumped together in one bucket to be able to squeeze 16 into 8.

 

If you have 16 buckets everything can be put into the right bucket.

But, as soon as you start postprocessing, data will be moved from one bucket into the other, lumping them together and making them irretrievable

 

If you have 32 buckets there will be empty buckets between the full ones, meaning that data will be kept separate in the next empty bucket when moving, enabling you to move them on once again, without loss.

 

Lightroom will apply the correct settings automatically and only processes in the right order when exporting the file, making 16 bits ample for most applications. But it does use Prophoto RGB, which is a larger colour space.

 

However, I would not recommend setting ACR to Prophoto RGB, as the gamut is so wide that it can be hard to judge the colours on your screen. Adobe RGB is fine, you won't be too far off (if anything, especially if your screen can render close to the Adobe RGB gamut), but Prophoto can be way out.

 

If you need to dumb down to sRGB, do so at the very end of your workflow. Colours pulled into a smaller gamut cannot be restored to a larger one.

[pgk]

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If you are planning very heavy postprocessing it is wise to use a 32 bits file, as that will preserve data and avoid posterizing.

 

Unfortunately, I don't think that this makes any difference whatsoever. 

[jaapv]

Not really for normal processing, that is true, but for instance HDR certainly benefits. There is no real downside either.

[FlashGordonPhotography]

I'm not looking at your system but here's what's happening.

 

The change from 16 bit to 8 bit is happening when you output the file from Lightroom. The LR default is set to output 8 bit files. You can change this in the Lightroom preferences.

 

However......

 

1. jpegs HAVE to be 8 bit. You can't have a 16 bit jpeg. So if you're working with jpeg files you have to work in 8 bit. For 16 bit storage you need to work with TIFFs or PSD files.

 

2. At some point you'll need to convert to 8 bit for viewing or uploading. The exception is output to printing. Most browsers, photo sharing sites, screens etc can't deal with a 16 bit file (or a TIFF or PSD file for that matter).

 

3. No displays can show a full 16 bits so you can't see them anyway. 16 bit files are great for the processing stage but when you get to output you'll want an 8 bit file for viewing and you won't see any difference on screen. The best monitors have 10 bit LUTs. Most are 6 or 8 bit. Again the exception is sending to print where better printers can utilise the extra bits in representing colour transitions and dithering.

 

4. It's highly unlikely that the S is actually capturing a full 16 bit range. It's more likely to be 14 or 15 bits in a 16 bit wrapper. And the advantage in 16 bit capture is partly in the extra dynamic range that can be captured. This capture advantage will be passed on to an 8 bit output file.

 

Gordon