Author Topic: Converted TIFFs only 8 bits per channel ?  (Read 4127 times)

Offline remko

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Converted TIFFs only 8 bits per channel ?
« on: September 05, 2010, 06:59:52 AM »

I am running PM 4.6.5 on a PowerPC Mac with 10.4.11

I just discovered that, when selecting edited RAW photos (NEFs in my case) and using the Save as command to have these photos converted to TIFFs, the resulted TIFFs are then in 8 bit per channel instead of 16 bits.

I could not find any preference setting to change this.

As I always edit my photos in Photoshop in 16 bits per channel for better quality, I find that I cannot use this very handy Save as command in PM in this particular situation.

Did I overlooked something ? And if not, any chance this will be changed, e.g. by giving an option in the Preference Pane for either 8 or 16 bits/channel ?

Cheers,
Remko

Offline Hayo Baan

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #1 on: September 05, 2010, 07:20:08 AM »
Remko,

When you save-as from a NEF, PM uses the embedded jpg as its source. While this is a high-quality jpg (especially true if you've edited the NEF in Nikon Capture NX), it nevertheless is still only 8-bit (like all jpgs).

Note that even if the source is 16-bit, PM will still only save as 8-bit.

The only way to get 16-bit tiffs out of a NEF, is to use (the batch facilities) of your raw converter.

Hope this helps,
    Hayo
Hayo Baan - Photography
Web: www.hayobaan.nl

Offline remko

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #2 on: September 05, 2010, 07:33:07 AM »

Hayo,

Thanks for your so quick reply and explanation. I now understand why PM does what it does in this respect.

Yes I am using Nikon's NX2.

A pitty though that PM is not supporting this, as it is such a fine program to use and I find myself always going back to it. For me PM is the default app to use and by browsing thru the various photos in PM, I then select which one to use. These images are already edited NEFs.

Any chance it will be possible to have 16 bits/channel TIFFs in a future release ?

Cheers,
Remko


Offline Kirk Baker

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #3 on: September 05, 2010, 08:48:23 AM »
Remko,

Yes I am using Nikon's NX2.

A pitty though that PM is not supporting this, as it is such a fine program to use and I find myself always going back to it. For me PM is the default app to use and by browsing thru the various photos in PM, I then select which one to use. These images are already edited NEFs.

Any chance it will be possible to have 16 bits/channel TIFFs in a future release ?

The source data (embedded JPEG) is only 8-bits/channel.  There would be no point in up-converting to 16 bits.  No additional quality would be obtained.

-Kirk

Offline remko

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #4 on: September 05, 2010, 10:10:57 AM »
Hi Kirk,

Thank you for your reply.

The quality obtained from starting with a 16 bit TIFF is when this file is used for additional editing. So, yes, there is something to win  :)
Hence my question.

I agree with you when having a 16 bit TIFF and *not* using that file for editing or printing. Than it is pointless, indeed.

Cheers,
Remko


Offline Kirk Baker

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #5 on: September 05, 2010, 11:04:25 AM »
Remko,

The quality obtained from starting with a 16 bit TIFF is when this file is used for additional editing. So, yes, there is something to win  :)
Hence my question.

I agree with you when having a 16 bit TIFF and *not* using that file for editing or printing. Than it is pointless, indeed.

You can easily change the bit-depth in Photoshop should you decide to continue to edit the file.  Otherwise you might as well leave it at 8-bit since the file will be half the size on disk.

-Kirk

Offline remko

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Re: Converted TIFFs only 8 bits per channel ?
« Reply #6 on: September 05, 2010, 11:25:07 AM »
Hi Kirk,

Thanks for being so responsive .... and that on a Sunday !

I am not quite sure if I understand you correctly.
Having a 8 bit file and making that a 16 bit one in Photoshop does not bring me anything. As Photoshop cannot, by some magic, add something that was thrown away before when the NEF was reduced to 8 bits. 

So I will use my RAW converter to convert a NEF to TIFF when I want to edit a picture.

Off topic, but I wanted to give you all this feedback already earlier: I am very impressed by the quality my JPEGs get when I use the sharpening routine within PM. I do not know what kind of algoritm is used, but the results are truly impressive  :) :)

cheers,
Remko