Which free software could acquire 48 bits color depth pictures from a scanner ?

In article , HEMI-Powered
wrote:

mark, my computer math is pretty rusty but what does 16 bit
floating point or whatever vs. 32 bit or even 64 bit have anything
at all to do with color depth?

it doesn't. photoshop uses 32 bit math internally (or 64 bit in cs4)
when making calculations on an 8 bit per channel image.

nospam added these comments in the current discussion du jour
....

mark, my computer math is pretty rusty but what does 16 bit
floating point or whatever vs. 32 bit or even 64 bit have
anything at all to do with color depth?

it doesn't. photoshop uses 32 bit math internally (or 64 bit
in cs4) when making calculations on an 8 bit per channel
image.

so, what does the bit width of the math to do with color depth at
all? if I understand your answer, nothing. so, while I have no skin
in this game, I'm curious as to the computer architecture side of
the issue regardless of whether 48 bit color does or doesn't make
sense in this instance.

thanks.

--
HP, aka Jerry

"Never attribute to malice that which can be adequately explained
by stupidity!" - Hanlon's Razor

In article , HEMI-Powered
wrote:

mark, my computer math is pretty rusty but what does 16 bit
floating point or whatever vs. 32 bit or even 64 bit have
anything at all to do with color depth?

it doesn't. photoshop uses 32 bit math internally (or 64 bit
in cs4) when making calculations on an 8 bit per channel
image.

so, what does the bit width of the math to do with color depth at
all? if I understand your answer, nothing.

basically, speed.

Guilbert STABILO wrote:
Hi all,

I need to scan some old films using a 48 bits color depth (in order to keep
the quality after some graphical process).
My Canon CS5200F does it well but none of my graphical softwares can handle
48 bits picture.

The GIMP 2.6.2 translated my pictures from 48 to 24 bits.

Which may or may not actually make any difference to
you! The 8 bit internal format used by GIMP is gamma
corrected (intended to cause equal value changes to
result in approximately equal brightness changes in a
viewed image). Unless you are going to make large
changes using curves or levels, which will compress data
in some parts of the range and expand data in others, it
won't be important. For example, if you want the
scanned image to look *exactly* like the original film
image, it won't be a problem. If you want to do major
color correction or large gamma adjustments, then it
will.

Still, for minor adjustments that isn't a problem, but for
major changes it is.

I typically use /Cinepaint/, a free program with a user
interface that is almost identical to GIMP, for those
cases where 16-bit color depth is required.

IrfanView does the same as the GIMP (48 = 24).
I also tried XnView which is supposed to handle 48 bits pictures but when
the picture is transfered from the scanner, I get a black screen (I tried
in 24 bits and got the correct picture so this is really a color depth
problem).

I heard that the GIMP 2.6.2 was using a module called GECL which handles 48
bits pictures but I did not find any to configure/activate it : my pictures
are always handled as 24 bits picture.

At this point you have to use the Colors-Use_GEGL menu
item to enable the use of GEGL. However, while GEGL can
handle 16-bit depth images, the rest of GIMP, including
the internal image format, is still restricted to using
8-bit depth images. I do not know what the status of
that work is at this time. The 2.7 development thread
to date has shown nothing yet going in that direction,
so while it might happen before 2.8 is released it isn't
yet obvious.

I do not want to buy any graphical software because many free ones exist.

= Do you know any free software or plugin which could work with 48 bits
pictures acquired from a scanner ?

Get /cinepaint/.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

nospam wrote:
NeilMolon

I guess that's why everyone is raving about CS4 finally supporting some 32-bit
math in some of its functions.

actually they're raving about cs4 being *64 bit*.

Too many people with too little understanding.

32-bit pixels is different from being able to handle a 64-bit address
space. Whining that PS cn't do 32-bit pixels for all functions is
silly given that there's no output device that can handle even a
16-bit range.

--
Ray Fischer

In article , Ray Fischer
wrote:

32-bit pixels is different from being able to handle a 64-bit address
space.

right.

Whining that PS cn't do 32-bit pixels for all functions is
silly given that there's no output device that can handle even a
16-bit range.

16 bit printing is supported on cs4/mac.

On 16 Nov 2008 17:11:01 GMT, Guilbert STABILO
wrote:

Hi all,

I need to scan some old films using a 48 bits color depth (in order to keep
the quality after some graphical process).
My Canon CS5200F does it well but none of my graphical softwares can handle
48 bits picture.

The GIMP 2.6.2 translated my pictures from 48 to 24 bits.
IrfanView does the same as the GIMP (48 = 24).
I also tried XnView which is supposed to handle 48 bits pictures but when
the picture is transfered from the scanner, I get a black screen (I tried
in 24 bits and got the correct picture so this is really a color depth
problem).

I heard that the GIMP 2.6.2 was using a module called GECL which handles 48
bits pictures but I did not find any to configure/activate it : my pictures
are always handled as 24 bits picture.

I do not want to buy any graphical software because many free ones exist.

= Do you know any free software or plugin which could work with 48 bits
pictures acquired from a scanner ?

Thanks in advance for your help.

It's not free but Photo Paint will handle 48 bit RGB.



Eric Stevens

nospam added these comments in the current discussion du jour
....

mark, my computer math is pretty rusty but what does 16
bit floating point or whatever vs. 32 bit or even 64 bit
have anything at all to do with color depth?

it doesn't. photoshop uses 32 bit math internally (or 64
bit in cs4) when making calculations on an 8 bit per
channel image.

so, what does the bit width of the math to do with color
depth at all? if I understand your answer, nothing.

basically, speed.

I DO understand that, IF the entire HW/SW system can support a
wider floating point math data I/O path. Still, that has no-thing
to do with 24 vs 48 bit color depth.

--
HP, aka Jerry

"Never attribute to malice that which can be adequately explained
by stupidity!" - Hanlon's Razor

On Sun, 16 Nov 2008 14:00:31 -0600, "HEMI-Powered" wrote:

mark raif added these comments in the current discussion du jour
...

[snip]
If you save your scans in CMYK format then it will even
properly handle 64-bit color-depths. It's the only software
that I know of that can do this. PhotoShop still only uses
16-bit math for most of its tools and functions. Wholly
incapable of retaining all that extra data during any
processing of these larger bit-depths. This has been a thorn
in the side of the "pro" world for the last 2 decades of using
PhotoShop, but they all seem to ignore it and live with it.
Only recently has Adobe started to add in some 32-bit math
routines to only some of their tools and features, but by no
means do all PhotoShop tools and filters use 32-bit math.
They're still working on it. Photoline has been a fully 32-bit
math platform for the last 15 years.

mark, my computer math is pretty rusty but what does 16 bit
floating point or whatever vs. 32 bit or even 64 bit have anything
at all to do with color depth? Or, am I misunderstanding you? Is
what you're really saying that PS will cut down the color depth
back to 24 bit, do the function, then step it back up to 48 which
is pointless?

While all operating systems can load and view 32 and 64 bit color-depths
(usually by averaging to lower bit-depths if your display and software can't
handle it), that is where it ends. The moment you use an editor with only 16-bit
math you are starting to truncate valuable data during each process due to
rounding errors. Most will never notice it due to the limitations of their
display, but this loss does exist. This is why they put up with it in PhotoShop
for so long, what you can't see won't hurt you. For those that paid dearly to
get every bit-depth in their images they would like to have all that information
retained.

Let's say for example that you only have a 4-bit depth math package. 4-bit
floating-point math means that only FOUR significant binary characters can be
used to do the math. Any operation done on any color values will be truncated by
averaging mathematically. A decimal (not binary) example: If you have an RGB
pixel's red value of 38756 on a 16-bit color depth (values of 0 to 65535), and
you want to reduce that by 33%, you end up with a value of 12789.48. In a 4-bit
math platform that is rounded to 12790.00 Only 4-significant digits may be used,
the 89.48 is rounded to a value of 90. (Keeping in mind that in a 4-bit math
depth which is all performed in binary, using values 0-7, so the significant
digits in decimal (values 0-9) as presented here for examples, becomes much less
than this, even greater rounding is done sooner. This is only provided as a
quick example of what happens.) As more editing operations are performed those
approximated color values will carry over their errors and be duplicated. Each
time an operation is performed on that data then more math errors will be
introduced, always being rounded-off (lost) in the math functions. This is why
it's a good rule-of-thumb to always use at least the same or higher
floating-point math depth as your image color-depth. Perform 2 or more
operations on any set of pixels with a lower bit-depth math platform and you may
have drastically changed your color values by the time you are done. This is
precisely why PhotoShop could never incorporate the more advanced Lanczos-8
resampling algorithms. Its math platform was/is just incapable of doing the
calculations necessary to retain the image details during rotations and
resizings. The best that PhotoShop could ever offer was (and is) simplistic
bicubic interpolations, always resulting in muddy images and soft edges due to
lost details every time those operations are performed.


This is the first I've ever heard of Photoline, but then I'm hardly
a pro. But, 15 years ago? What motherboard or CPU was even remotely
capable of floating point math at 32 bits/channel? Or, am I again
misunderstanding you?

32-bit math has been around since Windows 3.1 if you installed the System32 math
package, and more commonly found in the very first versions of Windows 95, the
very first version of Win95 happening in 1993 (if you were one of the alpha
testers for MS, as I was). Windows 3.1 was primarily 16-bit math but allowed you
to use 32-bit software if your CPU allowed for it and if you installed some
accessory files (the origin of the "system32" Windows folder, there used to be
just a "system" folder in Win3.1). Photoline, originally called Photoline32,
recently renamed to just Photoline, was named that just because it was the ONLY
graphic editor that fully supported the new 32-bit math platform that started
during the Windows 3.1 to Window 95 bridge years.

A slight error, checking online I see now that Photoline32 was released in 1995.
I only know I was using it on the very first versions of Windows 95 when Win95
was released to the public (as the Windows-95 beta version due to a marketing
lawsuit that Gates didn't want to deal with, in-house memos that I was privy
to). The 2 year discrepancy about Photoline due to my alpha-testing phase of
Windows 95 which started in 1993. I only recall that I latched onto Photoline as
soon as I discovered its existence. It's been the backbone of my graphic editing
platform all these years due to how much more it can do and how much more
accurately it can do it. If someone hands me a complimentary copy of Photoshop,
I merely thank them, then after they have left I throw it in the waste-basket,
where it's always belonged. I wouldn't dare even give it to a friend, I wouldn't
want them to have to put up with that Adobe nonsense.

In article , mark raif
wrote:

32-bit math has been around since Windows 3.1

32 bit math was available *long* before that.

If someone hands me a complimentary copy of
Photoshop,
I merely thank them, then after they have left I throw it in the waste-basket,
where it's always belonged. I wouldn't dare even give it to a friend, I wouldn't
want them to have to put up with that Adobe nonsense.

so ebay it to a stranger.