Re: 16-bit Printing
Re: 16-bit Printing
- Subject: Re: 16-bit Printing
- From: "Roy Harrington" <email@hidden>
- Date: Thu, 20 Nov 2008 23:18:44 -0800
I decided to look into this a while back. A major issue in this is
how you (i.e.
the program) converts from 16-bit to 8-bit. Photoshop and the CMSs dither
the 8-bit values to more accurately represent the 16-bit input. In other words
a 16-bit value that lies between say 127 and 128 is not just truncated
to 127 but
instead has a mix of 127 and 128 valued pixels. Anyway if the values are
dithered it's OK to send just 8-bits but if they are truncated you can
potentially see
steps. Sometimes it's possible to see steps on a high quality monitor because
this dithering is not usually done on displays.
I think this makes sense because for the current inkjet printers there
is a lot of
dithering needed to represent many levels -- Epsons have at most 3 drop sizes.
Breaking the dithering into two stages does not cause any harm.
I did some tests that showed that 8-bits was enough. In fact I was
unable to tell
any difference with as few as 6-bits. If you are interested I wrote a brief
description of the tests I did: http://harrington.com/bitinfo.html
Roy
On Wed, Nov 19, 2008 at 2:08 PM, Fleisher, Ken <email@hidden> wrote:
> The benefits of editing in a 16-bit/channel image vs. an 8-bit/channel image
> are clear, but I have a question about printing a 16-bit/channel image. Some
> new printers with larger color gamuts are now becoming available and the
> ability to transmit a full 16-bit/channel image to the printer is now
> possible. The usual claim is that with the larger color gamut, you can get
> smoother gradients with the 16-bit print path vs. an 8-bit, or even 12-bit,
> print path.
>
> I have not seen any results from one of these printers that can accept a
> full 16-bits/channel and I¹m wondering if those of you who have experience
> with them, can you describe what you have seen? Do you feel there is any
> real benefit to printing a full 16-bit image? Can you actually ³see² a
> difference? If so, is it a significant difference?
>
> I¹m skeptical that there a real need for sending a full 16-bits/channel to
> the printer, so I am looking forward to the discussion to come!
>
> Thanks.
>
> --
> Ken Fleisher
>
> Photographer
> Imaging & Visual Services
> National Gallery of Art
> Washington, D.C.
>
> Phone: (202) 712-7471
> email@hidden
>
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