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16-bit mode is actually 15-bit (maximum values are 32,767), according to
the Info tool.

Is this internal, or a bug in the Info tool?
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

(E-Mail Removed) wrote in message news:<(E-Mail Removed)>. ..
> 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> the Info tool.
>
> Is this internal, or a bug in the Info tool?

As Mr Cox will be delighted to inform you, Photoshop's "16"-bit mode
is indeed quasi-15-bit, channels have an internal range of 0-32768
(inclusive). See this recent discussion on Adobe Forums:
http://www.adobeforums.com/cgi-bin/w...cs.8@.3bb3f466

Adobe does not seem to consider it a bug, but those who need to work
with 16 bit data may disagree.

T

In article <(E-Mail Removed)>, (E-Mail Removed) wrote:

> 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> the Info tool.
>
> Is this internal, or a bug in the Info tool?

32767 is 16-bit signed integer max. I wonder what they use the <0 values for.

Who said it was signed?

The range is 0 to 32768.

Chris



In article <john-(E-Mail Removed)>, jjs
<(E-Mail Removed)> wrote:

> In article <(E-Mail Removed)>, (E-Mail Removed) wrote:
>
> > 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> > the Info tool.
> >
> > Is this internal, or a bug in the Info tool?
>
> 32767 is 16-bit signed integer max. I wonder what they use the <0 values for.

In article <160520041717368533%(E-Mail Removed)>, Chris Cox
<(E-Mail Removed)> wrote:

> Who said it was signed?

Not me. I only set the bait.

> The range is 0 to 32768.

And that's plenty.

(E-Mail Removed) (jjs) wrote in message news:<john-(E-Mail Removed)>...
> In article <(E-Mail Removed)>, (E-Mail Removed) wrote:
>
> > 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> > the Info tool.
> >
> > Is this internal, or a bug in the Info tool?
>
> 32767 is 16-bit signed integer max. I wonder what they use the <0 values for.

Photoshop's quasi-15-bit upper value is +32768, so the 16 bit value is
regarded as unsigned. (See Adobe Forums thread cited above.)

T

(E-Mail Removed) (jjs) wrote in message news:<john-(E-Mail Removed)>...
> In article <(E-Mail Removed)>, (E-Mail Removed) wrote:
>
> > 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> > the Info tool.
> >
> > Is this internal, or a bug in the Info tool?
>
> 32767 is 16-bit signed integer max. I wonder what they use the <0 values for.

Photoshop's quasi-15-bit upper value is +32768, so the 16 bit value is
regarded as unsigned. (See Adobe Forums thread cited above.)

T

In article <(E-Mail Removed) >,
(E-Mail Removed) (Toby Thain) wrote:

> (E-Mail Removed) (jjs) wrote in message
news:<john-(E-Mail Removed)>...
> > In article <(E-Mail Removed)>, (E-Mail Removed) wrote:
> >
> > > 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> > > the Info tool.
> > >
> > > Is this internal, or a bug in the Info tool?
> >
> > 32767 is 16-bit signed integer max. I wonder what they use the <0
values for.
>
> Photoshop's quasi-15-bit upper value is +32768, so the 16 bit value is
> regarded as unsigned. (See Adobe Forums thread cited above.)

It wasn't me who first mentioned 2^16-1. I was just responding to the
person who did.

(E-Mail Removed) (jjs) wrote in message news:<john-(E-Mail Removed)>...
> In article <(E-Mail Removed)>, (E-Mail Removed) wrote:
>
> > 16-bit mode is actually 15-bit (maximum values are 32,767), according to
> > the Info tool.
> >
> > Is this internal, or a bug in the Info tool?
>
> 32767 is 16-bit signed integer max. I wonder what they use the <0 values for.

Photoshop's quasi-15-bit upper value is +32768, so the 16 bit value
should be regarded as unsigned. (See Adobe Forums thread cited above.)

T

Chris Cox <(E-Mail Removed)> writes:

> Who said it was signed?
>
> The range is 0 to 32768.

Which is just beyond a 15-bit unsigned integer. 2^16 was 65,536, last
I checked. That said, I don't know of any digital camera that gives
even 15 useful bits, much less 16.

<snip>

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.