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Scanners and 48 bit data

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Anonymous
February 22, 2005 11:51:06 AM

Archived from groups: rec.photo.digital (More info?)

Most scanners claim to provide 48 bit data. What application software
can use 48 bit data? PS, PSP, ??

Does the Twain standard import 48 bit data from scanner to application?

If I want to save the image before I am finished editing it, what file
formats retain 48 bit color depth?

More about : scanners bit data

Anonymous
February 22, 2005 11:51:07 AM

Archived from groups: rec.photo.digital (More info?)

Both Photoshop and Photoshop Elements 3 will work in 48 bit mode and
yes you can get the file through the twain interface.

For saving the file in 48 bit more I use the native file for Photoshop,
psd files, you can also save in a number of other formats including jpg
2000 and tiff.

Scott
Anonymous
February 22, 2005 11:51:07 AM

Archived from groups: rec.photo.digital (More info?)

All Things Mopar wrote:
> Scott W commented courteously ...
>
> > Both Photoshop and Photoshop Elements 3 will work in
> > 48 bit mode and yes you can get the file through the
> > twain interface.
> >
> > For saving the file in 48 bit more I use the native
> > file for Photoshop, psd files, you can also save in
> > a number of other formats including jpg 2000 and tiff.
>
> Scott, being a PSP 9 user with no knowledge of PS at all,
> does PS and PSE really do everything in 48 bit?
>
> 48-bit color comes up fairly often these days in a variety
> of NGs. Again, being ignorant of 48-bit color, I always
> ask people "can you tell the difference vs. 24-bit?" and
> "on what do you display it or print it?".
>
> Not to mention, I have to ask "what original could
> possibly be scanned with a 48-bit scanner that actually
> has that many colors?"
>
> Last I looked, Windoze was 32-bit, and the extra 8 bits
> are for transparency, rather than additional colors.
>
> --
> ATM, aka Jerry
I don't know about PS but PSE 3 will do a lot in 48 bit mode but not
all. It is handy to work in 48 bit mode as you have more dynamic range
and you can do repeaded adjustments to the levels with out degreading
the image, once you convert to a 24 bit bitmap you can't tell the
differnace.

Scott
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Anonymous
February 22, 2005 1:08:53 PM

Archived from groups: rec.photo.digital (More info?)

Scott W commented courteously ...

> Both Photoshop and Photoshop Elements 3 will work in
> 48 bit mode and yes you can get the file through the
> twain interface.
>
> For saving the file in 48 bit more I use the native
> file for Photoshop, psd files, you can also save in
> a number of other formats including jpg 2000 and tiff.

Scott, being a PSP 9 user with no knowledge of PS at all,
does PS and PSE really do everything in 48 bit?

48-bit color comes up fairly often these days in a variety
of NGs. Again, being ignorant of 48-bit color, I always
ask people "can you tell the difference vs. 24-bit?" and
"on what do you display it or print it?".

Not to mention, I have to ask "what original could
possibly be scanned with a 48-bit scanner that actually
has that many colors?"

Last I looked, Windoze was 32-bit, and the extra 8 bits
are for transparency, rather than additional colors.

--
ATM, aka Jerry
Anonymous
February 22, 2005 2:06:51 PM

Archived from groups: rec.photo.digital (More info?)

Don Stauffer in Minneapolis wrote:
> Most scanners claim to provide 48 bit data. What application software
> can use 48 bit data? PS, PSP, ??
>
> Does the Twain standard import 48 bit data from scanner to application?
>
> If I want to save the image before I am finished editing it, what file
> formats retain 48 bit color depth?


Photoshop certainly can use and manipulate 48 bit
image files. ACDSee can usually view them (but
sometimes chokes on very big ones.)

..PSD and .TIF formats can be used to save these files.

I don't know much about TWAIN anymore. In Windoze
it's been superceded by WIA, but in any case I find
myself using standalone apps, both for my scanners
and my digicams.


rafe b.
http://www.terrapinphoto.com
Anonymous
February 22, 2005 2:56:09 PM

Archived from groups: rec.photo.digital (More info?)

Scott W commented courteously ...

> I don't know about PS but PSE 3 will do a lot in 48
> bit mode but not all. It is handy to work in 48 bit
> mode as you have more dynamic range and you can do
> repeaded adjustments to the levels with out degreading
> the image, once you convert to a 24 bit bitmap you
> can't tell the differnace.

Thanks, Scott.

So, you're working on the histogram and other aspects of
the image that can benefit from the additional bit width?

I hang out on a couple PSP news groups, where 48-bit color
comes up often. Natually, the Corel crowd pooh-poohs this,
but I'm sure they are working on it.

However, some of the very creative photographers and
digital artists always ask "where's the beef?". One or 2
steadfastly maintain that nearly all of the extra 48 bits
is just noise at each end of the histogram.

Natually, I don't know, since I don't have a camera or a
scanner which will go beyond 24-bit. And, if you've seen
any of my posts, my requirements as well as my PSP 9
expertise, is a long ways below where I'd see any
advantage to 48-bit. But, I'm trying to stay on top of the
growing trend in the industry so I am ready for it when it
becomes of interest to me.

>
> Scott
>
>



--
ATM, aka Jerry
Anonymous
February 22, 2005 7:42:53 PM

Archived from groups: rec.photo.digital (More info?)

In article <Xns9605716827A6AReplyToken@216.196.97.131>,
All Things Mopar <usenetMAPS123@comcast.net> wrote:

>48-bit color comes up fairly often these days in a variety
>of NGs. Again, being ignorant of 48-bit color, I always
>ask people "can you tell the difference vs. 24-bit?" and
>"on what do you display it or print it?".

I think, you may be asking the wrong question. The real use for 48 bit
colour is to avoid quantisation problems (clipping and rounding) which occur
due to image processing and the use of wide-gamut colourspaces (e.g.
Adobe-RGB). For final presentation, 24bpp is perfectly adequate, but 48bpp
is useful as a working format to avoid image degredation.
Anonymous
February 22, 2005 7:42:54 PM

Archived from groups: rec.photo.digital (More info?)

Chris Brown commented courteously ...

> I think, you may be asking the wrong question.

I probably am asking the wrong question, Chris, as I don't
understand enough about this nor have any hardware that I
can use to test my "theories".

> The real use for 48 bit colour is to avoid
> quantisation problems (clipping and rounding)
> which occur due to image processing and the use of
> wide-gamut colourspaces (e.g. Adobe-RGB).

I understand Adobe RGB vs. the "standard" sRGB color
space, but not very well. Are you doing your image
processing on RAW images, I assume?

> For final presentation, 24bpp is perfectly adequate,
> but 48bpp is useful as a working format to avoid image
> degredation.

I'm aware from talking to friends in Chrysler's Photo
Imaging department that there *are* things you can "see
with 32-bit or 48-bit color, I've been shown examples of
banding and posterization in 24-bit that go away with high
width. But, these guys have hundreds of thousands of
dollars invested in computer hardware, cameras, printers,
and color calibration software/hardware.

With that bloviating preface, could you continue my
education and explain briefly what you mean by "avoiding
image degradation"?

Thanks, Chris.

--
ATM, aka Jerry
Anonymous
February 22, 2005 8:39:10 PM

Archived from groups: rec.photo.digital (More info?)

"What application softwre can use 48 bit data?" The ones I know about are

PhotoShop CS

PhotoShop Elements 3 (limited)

Picture Window Pro

Corel PhotoPaint

CinePaint (customized version of "The GIMP" ...
but it's pretty much a "rolling alpha release" at this point)

"If I want to save the image before I am finished editing it, what file
formats retain 48 bit color depth?" The ones I know about are


PhotoShop (PSD)

TIFF

*Probably* Corel PhotoPaint's proprietary format




"Don Stauffer in Minneapolis" <stauffer@usfamily.net> wrote in message
news:380v6rF5il93oU3@individual.net...
> Most scanners claim to provide 48 bit data. What application software
> can use 48 bit data? PS, PSP, ??
>
> Does the Twain standard import 48 bit data from scanner to application?
>
> If I want to save the image before I am finished editing it, what file
> formats retain 48 bit color depth?
Anonymous
February 22, 2005 9:28:39 PM

Archived from groups: rec.photo.digital (More info?)

All Things Mopar wrote:
[]
> Natually, I don't know, since I don't have a camera or a
> scanner which will go beyond 24-bit. And, if you've seen
> any of my posts, my requirements as well as my PSP 9
> expertise, is a long ways below where I'd see any
> advantage to 48-bit. But, I'm trying to stay on top of the
> growing trend in the industry so I am ready for it when it
> becomes of interest to me.

Actually, you have a Nikon 5700 which shoots in RAW mode if you wish. I
understand that in that mode you get 12 bits per colour, so you can
already generate 36-bit images. The 12-bit data is a linear value, the
8-bit JPEG data nearer a log or gamma-corrected value, so the available
dynamic range is similar in each, but the accuracy of representation in
the 8-bit data isn't as high as in the 12-bit data. {But does that
matter?]

Broadly speaking, it's one of those awkward choices - 8 bits per colour is
fine if everything is 100% exposed correctly and the dynamic range of the
scene isn't too large. Having the 12-bit data gives you a little more
margin. But computers work better with either 8-bit or 16-bit colours
rather than 12-bit, so your choice is between 24-bit RGB and 48-bit RGB.
By the way, there are those who argue that PhotoShop only works with
15-bit colour data, not 16-bit data. Whatever, the lower few bits are
just noise.

Cheers,
David
Anonymous
February 22, 2005 9:28:40 PM

Archived from groups: rec.photo.digital (More info?)

David J Taylor commented courteously ...

> Actually, you have a Nikon 5700 which shoots in RAW
> mode if you wish. I understand that in that mode you
> get 12 bits per colour, so you can already generate
> 36-bit images.
[snip]

Didn't know that about my NEF files. Thanks, David!

> Broadly speaking, it's one of those awkward choices
> - 8 bits per colour is fine if everything is 100%
> exposed correctly and the dynamic range of the scene
> isn't too

That makes perfect sense to me...

> Having the 12-bit data gives you a little more
> margin. But computers work better with either
> 8-bit or 16-bit colours rather than 12-bit, so your
> choice is between 24-bit RGB and 48-bit RGB.

Yes, computers have to be on even byte boundaries,
although these days, I believe that the CPU operates most
often on a 32-bit "word".

> By the way, there are those who argue that PhotoShop
only
> works with 15-bit colour data, not 16-bit data.
> Whatever, the lower few bits are just noise.

That's exactly what I've heard/read, but I wasn't sure
enough of my "facts" to be dogmatic with my post.

Thanks for the clarifications...

--
ATM, aka Jerry
Anonymous
February 22, 2005 11:28:53 PM

Archived from groups: rec.photo.digital (More info?)

In article <Xns9605846F66D33ReplyToken@216.196.97.131>,
All Things Mopar <usenetMAPS123@comcast.net> wrote:
>
>> The real use for 48 bit colour is to avoid
>> quantisation problems (clipping and rounding)
>> which occur due to image processing and the use of
>> wide-gamut colourspaces (e.g. Adobe-RGB).
>
>I understand Adobe RGB vs. the "standard" sRGB color
>space, but not very well. Are you doing your image
>processing on RAW images, I assume?

RAW images and scanned film. The latter almost certainly doesn't pick up
anything but noise in the least significant 8 bits of each channel, but I
work in 48 bits to avoid quantisation losses whilst processing in Photoshop.

>> For final presentation, 24bpp is perfectly adequate,
>> but 48bpp is useful as a working format to avoid image
>> degredation.
>
>I'm aware from talking to friends in Chrysler's Photo
>Imaging department that there *are* things you can "see
>with 32-bit or 48-bit color, I've been shown examples of
>banding and posterization in 24-bit that go away with high
>width.

You can construct examples within a 24 bit range where the transitions
between adjacent bands can be seen, but it's generally not a problem in real
photographic images.

But this does highlight the reason to work in 48 bits - 24 bits is only just
adequate for display, as you have hinted at above. Processing the image will
lose some of the useful information in the low-order bits. By switching to
48 bits for processing, those low-order bits don't contain anything useful
anyway. If you process in 24 bits, however, you may well end up with an
image that only has, say, 18 bits worth of real information at the end.

>With that bloviating preface, could you continue my
>education and explain briefly what you mean by "avoiding
>image degradation"?

An analogy may help - imagine you have the following set of numbers, which
represent some image data:

12
4
25
8
13

Now we want to do some operation on them, which represents some operations
in Photoshop - let's divide them all by 3 and add them, but we'll do it
twice - once using just integers throughout, and again using one decimal
place:

divide by 3:

4 4.0
1 1.3
8 8.3
2 2.6
4 4.3

Now let's total them:

19 20.5

Even if we present our final result as an integer, we have got a more
accurate answer by working at a higher precision in the second case. That's
the main benefit from working in 48 bits - you keep the fractional parts of
operations, parts which get discarded in 24 bits. After a lot of processing,
all those missing fractions add up (or rather, don't).
Anonymous
February 22, 2005 11:28:54 PM

Archived from groups: rec.photo.digital (More info?)

Chris Brown commented courteously ...

[snip]
> You can construct examples within a 24 bit range where
> the transitions between adjacent bands can be seen, but
> it's generally not a problem in real photographic
images.

This makes sense...

[snip]
> An analogy may help - imagine you have the following
> set of numbers, which represent some image data:
[snip]

Yes, that does help. I now have a better understanding of
the underlying mathematics of this, as looked at from a
raster graphics format.

And, this tells me that it'll be a *long* time, if ever,
before I get into situations with my "documentary"-style
digital photography where either RAW or 48-bit color would
be useful! <grin>

Thanks for the explanation!

--
ATM, aka Jerry
Anonymous
February 23, 2005 1:55:22 PM

Archived from groups: rec.photo.digital (More info?)

All Things Mopar wrote:
>
> I'm aware from talking to friends in Chrysler's Photo
> Imaging department that there *are* things you can "see
> with 32-bit or 48-bit color, I've been shown examples of
> banding and posterization in 24-bit that go away with high
> width. But, these guys have hundreds of thousands of
> dollars invested in computer hardware, cameras, printers,
> and color calibration software/hardware.
>
> With that bloviating preface, could you continue my
> education and explain briefly what you mean by "avoiding
> image degradation"?
>
> Thanks, Chris.
>

The choice of either clipping or compressing (curve shaping).

This problem predates the digital camera. It was a problem in film
also. Photographic paper had a density range of less than 2 (it is
about 50:1 in best papers). Negative film, however, has a wider density
range, most a density of three (1000:1), some even more.

It was never possible to print the whole tonal range one found in a good
neg onto paper. One had a number of choices. Print for shadow detail
(concentrate on blacks), print for highlight detail (concentrate on
whites), or use a lower contrast paper that compressed the range of the
tonal range, lowering contrast but retaining both ends of the range.

We can do the same thing even more easily with digital, since contrast
changes and curve bending are simple clicks of a mouse. But you cannot
print data that isn't in the file. Having more dynamic range in the
original file (whether from camera or scanner) allows you the same
creative choice that film printers had. One does not need to clip or
compress until ready for the final print, and you can choose which to do.

If one is scanning prints, it is a moot point 'cause the prints have
limited range themselves, but with a transparency/negative adapter, I
will be working with wider dynamic range originals.
Anonymous
February 24, 2005 11:49:20 AM

Archived from groups: rec.photo.digital (More info?)

> If one is scanning prints, it is a moot point 'cause the prints have
> limited range themselves, but with a transparency/negative adapter, I
> will be working with wider dynamic range originals.
>
I have a couple of discussions on the value of 16 bit over 8 bit files
in the tips section of my web site. Many people claim not to be able
to see a difference, but I feel that starting with 16 bit before doing
any large amounts of contrast or brightness adjustment improves the
final image slightly.
Take a look at the tests and judge for yourself.

--
Robert D Feinman
Landscapes, Cityscapes and Panoramic Photographs
http://robertdfeinman.com
mail: robertdfeinman@netscape.net
!