Digital BW, The Print

> From: Ken Carney
>
> This is not quite on point with the thread, but perhaps you can shed some
> light.  I recently did a project in CRW, converted to 16-bit tif.  The
> printer wanted me to do the CMYK conversion according to their
> press specs,
> which I did.  The design consultant says the CMYK images have excess noise
> when converted from 16-bit to 8-bit to lay out in Quark.  I said
> fine, I'll
> convert the 16-bit RGB files to 8 and send to you, and you can have the
> press do the CMYK conversion.  I'll be there with match prints at
> the press.
> The design consultant indicates that any conversion from 16 to 8
> adds noise
> and banding because an extra 1/2 bit of noise is introduced in the PS
> conversion, and that for press work it is preferable to shoot in 8-bit jpg
> initially.  Well, there goes my custom white balance (WhiBal cards applied
> to the same image in Capture One).  I tried these conversions and on my
> screen (OptiCal calibrated LCD) could see no differences of any kind.  Do
> you or others on the list by chance know if this is BS or if there is
> something I'm missing?  Thx for any help.

Well, I don't see how shooting 8-bit JPEG in the first place could possibly
help.

8-bit might cause posterization, but PS at least claims to have an option
that adds dither noise when doing color space conversions in 8-bit mode,
which should avoid posterization. I have no experience with CMYK, so I don't
know if there are any special issues there.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...