A bug & note on using .png graphics....

[Art Campbell]

Stuff cut in below...

On 5/5/06, Combs, Richard <richard.combs at polycom.com> wrote:

<snip>
> Like I said, I'm no expert, but I've never heard the term "8-bit" used
> to describe an image that uses 24 bits to define each pixel, and I'd be
> very surprised if Photoshop uses the term that way.

OK, be prepared to be surprised. Pull down the Image menu, go to Mode and
gaze at the two entries "8 Bits / Channel" and "16 Bits / Channel."
I've been using it for years; it ain't new.

Of course, Adobe may not be paying attention to wikipedia's bloggers.....

> Color depth is generally specified as "bits per pixel (bpp)" -- see this
> Wikipedia topic:
>
> http://en.wikipedia.org/wiki/Color_depth
<snip>

Yes, the Wikipedia article seems to verify what I was saying; that the same file
can be referred to a 8-bit or 24-bit and both terms can be correct,
depending on how you
apportion the bits.

http://www.luminous-landscape.com/tutorials/bit-depth.shtml, among
other industry sources ...

> As for the RGB color definitions, I'm confused as to whether your files
> have them or not. Do you see hundreds of color definitions of the form
> "RGB 000, 082, 044"? If so, there are (or were) palettized 256-color PNG
> graphics in the FM doc. AFAIK, that's the only place from which they can
> come.

Yes, it is confusing. The short answer is no and yes.

No, the problem files I was referring to in the original message DO
NOT have the color definitions (working in 7.2).

The slightly more complex answer is that after I read the explanation
online last night,
I did a quick import of a .png on my home machine, and yes, there they
were (in 7.1).

>
> If all your PNGs are/were 16-million-color files, you shouldn't have
> hundreds of defined RGB colors in the doc.

I agree.

Cheers,
Art

--
Art Campbell                                             art.campbell at gmail.com
  "... In my opinion, there's nothing in this world beats a '52 Vincent
               and a redheaded girl." -- Richard Thompson
                             No disclaimers apply.
                                     DoD 358