Digital BW, The Print

1Ds MK II all work in 16 bit.


> From: "Paul D. DeRocco" <pderocco@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Mon, 10 Jan 2005 13:58:17 -0800
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: RE: [Digital BW] Posterization in red channel
> 
> 
>> From: Steve Kale [mailto:stevekale@...]
>> 
>> Hi. I am just working up an image from my new digital camera and
>> have come across
>> something that is puzzling me.  The colour image looks great - no
>> posterization and no
>> apparent clipping in any channel.  From the RAW file I used
>> Capture One Pro with high
>> contrast setting and simply slid the RGB black point slider up to
>> the left of the red
>> histogram and then processed (no other adjustments).  In PS, I
>> then used the split
>> channels technique to work up a B&W version.  The image is of a
>> sand dune against a dark
>> (blue) sky.  My problem is that the red channel appears (on
>> screen - I have not printed it
>> yet) to be posterized in the sky.  I want to use the red channel
>> because it is giving me the
>> dark sky.  Any ideas as to why this would be?  I can go back to
>> the original RAW file if need
>> be.
> 
> If you have a very quiet camera, like a Canon 20D, and you make the mistake
> of converting to an 8-bit image, and then apply a curve, you may be able to
> see posterization. Noisier cameras provide enough dithering to break up the
> bands. Make sure you use 16-bit mode, at least until you're finished with
> any significant exposure or curve correction.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@...