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Saving RAW as TIF

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Anonymous
March 31, 2005 1:30:42 AM

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

I tried saving a RAW image as a tiff so I could play with it in PS5.5. I was
surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
the straight data from the ccd and that tif at least wouldn't compress it,
but why is it so much bigger?

Also, is there any advantage to working with the raw file as opposed to tif?

mike regish

More about : saving raw tif

Anonymous
March 31, 2005 1:30:43 AM

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

mike regish wrote:

> I tried saving a RAW image as a tiff so I could play with it in PS5.5. I was
> surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
> the straight data from the ccd and that tif at least wouldn't compress it,
> but why is it so much bigger?
>
> Also, is there any advantage to working with the raw file as opposed to tif?

You don't mention what camera you're using, but most use some
level of lossless compression when creating RAW files. This
is to save memory card space.

It sounds like you might be saving as 16 Bit TIFF.. I think
PS 5.5 can only handle 8 bit images so you're not gaining anything
by saving as 16 bit TIFF for editing.

You'll need Photoshop CS or Photoshop Elements 3.0 to do
proper 16 bit editing.
Anonymous
March 31, 2005 1:30:43 AM

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

I did not see this mentioned yet, in raw data there is only one 12 bit
value for each pixel, when this is converted into color data there now
needs to be three values for each pixel, even if these values are only
8 bits you now are storing 24 bits for each pixel where you were
storing 12 before, now it you are using 16 bits / color, this jumps to
48 bits per/pixel or 4 time the space for the raw data, add to that
some losselss compression in the raw file and you have a large increase
when saving to tiff.

Scott
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Anonymous
March 31, 2005 1:31:53 AM

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

"Scott W" <biphoto@hotmail.com> wrote in message
news:1112241978.713894.67750@l41g2000cwc.googlegroups.com...
>I did not see this mentioned yet, in raw data there is only one 12 bit
> value for each pixel, when this is converted into color data there now
> needs to be three values for each pixel, even if these values are only
> 8 bits you now are storing 24 bits for each pixel where you were
> storing 12 before, now it you are using 16 bits / color, this jumps to
> 48 bits per/pixel or 4 time the space for the raw data, add to that
> some losselss compression in the raw file and you have a large increase
> when saving to tiff.
>
> Scott

Okay, now I don't get it. Compression is compression. If you compress a
file it has to come back to it's original size so you can see it. How does
a RAW file act as a lossless compression without changing anything when you
open and close it? I thought a tiff file was "no" compression at all. Does
RAW have more to do with the file coming straight from the camera with
little or no changing of the file in the camera, regardless of settings?
Anonymous
March 31, 2005 2:08:15 AM

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

I'm using the Dimage Viewer software that came with the Minolta 7D. It has 2
choices for saving as tif-24 and 48 bit. The 48 bit was clicked when I
opened it. Is this the same thing you're referring to?

mike

"Jim Townsend" <not@real.address> wrote in message
news:114mpt2qh3t7t97@news.supernews.com...

> You don't mention what camera you're using, but most use some
> level of lossless compression when creating RAW files. This
> is to save memory card space.
>
> It sounds like you might be saving as 16 Bit TIFF.. I think
> PS 5.5 can only handle 8 bit images so you're not gaining anything
> by saving as 16 bit TIFF for editing.
>
> You'll need Photoshop CS or Photoshop Elements 3.0 to do
> proper 16 bit editing.
>
>
>
>
>
Anonymous
March 31, 2005 2:08:16 AM

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

mike regish wrote:

> I'm using the Dimage Viewer software that came with the Minolta 7D. It has 2
> choices for saving as tif-24 and 48 bit. The 48 bit was clicked when I
> opened it. Is this the same thing you're referring to?

Yes..

8 bit refers to how many bits in a single color. There are
three primary colors so the total is 8 x 3 = 24 bits.

With 48 bit you have 48 / 3 = 16 bits per color.

(Just another confusing thing :-)
Anonymous
March 31, 2005 7:23:27 AM

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

mike regish wrote:
> I'm using the Dimage Viewer software that came with the Minolta 7D. It has 2
> choices for saving as tif-24 and 48 bit. The 48 bit was clicked when I
> opened it. Is this the same thing you're referring to?
>
> mike

Hi Mike...

If it helps any, saying 8 or 24 in this context is the same thing :) 

8 bits times 3 colours = 24 bits total

and of course 16 bits times 3 colours = 48 bits.

Ken
Anonymous
March 31, 2005 7:23:28 AM

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

OK. I was wondering why the big difference.

Thanks.

mike

"Ken Weitzel" <kweitzel@shaw.ca> wrote in message
news:p 2K2e.858732$8l.748846@pd7tw1no...
>
> Hi Mike...
>
> If it helps any, saying 8 or 24 in this context is the same thing :) 
>
> 8 bits times 3 colours = 24 bits total
>
> and of course 16 bits times 3 colours = 48 bits.
>
> Ken
>
Anonymous
March 31, 2005 8:02:07 AM

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

mike regish wrote:
> I tried saving a RAW image as a tiff so I could play with it in PS5.5. I was
> surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
> the straight data from the ccd and that tif at least wouldn't compress it,
> but why is it so much bigger?
>
> Also, is there any advantage to working with the raw file as opposed to tif?
>
> mike regish
>
>
In spite of its name, a RAW file has been processed to some degree. A
TIFF file just stores 24 bits of information for each pixel, making very
large files.


--
Ron Hunter rphunter@charter.net
Anonymous
March 31, 2005 9:07:52 AM

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

On 3/30/05 10:31 PM, in article npCdnVJFVaa04NbfRVn-jA@comcast.com,
"Sheldon" <sheldon@XXXXXXXXsopris.net> wrote:

>
> "Scott W" <biphoto@hotmail.com> wrote in message
> news:1112241978.713894.67750@l41g2000cwc.googlegroups.com...
>> I did not see this mentioned yet, in raw data there is only one 12 bit
>> value for each pixel, when this is converted into color data there now
>> needs to be three values for each pixel, even if these values are only
>> 8 bits you now are storing 24 bits for each pixel where you were
>> storing 12 before, now it you are using 16 bits / color, this jumps to
>> 48 bits per/pixel or 4 time the space for the raw data, add to that
>> some losselss compression in the raw file and you have a large increase
>> when saving to tiff.
>>
>> Scott
>
> Okay, now I don't get it. Compression is compression. If you compress a
> file it has to come back to it's original size so you can see it. How does
> a RAW file act as a lossless compression without changing anything when you
> open and close it? I thought a tiff file was "no" compression at all. Does
> RAW have more to do with the file coming straight from the camera with
> little or no changing of the file in the camera, regardless of settings?
>
>
It is possible to compress a file on a lossless (no-loss) basis. An example
of this is in Photoshop when you save as a Tiff you are presented with a
second dialog box that lets you select, among others, LZW compression. If
you choose LZW the file compresses without loss. A similar thing happens
with raw files. When these files are opened they open back to their true
size.
March 31, 2005 11:43:58 AM

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

mike regish wrote:

> I tried saving a RAW image as a tiff so I could play with it in PS5.5. I was
> surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
> the straight data from the ccd and that tif at least wouldn't compress it,
> but why is it so much bigger?
>
> Also, is there any advantage to working with the raw file as opposed to tif?


There is an advantage to working with the raw file with the newer raw
converter plugin for PS CS and other raw converters like Nikon Capture
that allow adjusting curves in the raw image before it's converted. See
what your raw converter can do & use that as the first step. I find I
don't use photoshop for much using the tools in the raw converter to
adjust brightness and contrast most of the time. Once it's adjusted,
it's OK to save in 8-bit (jpeg even) but if you are going to do curves &
levels, it's best to start with 16 bit, then crunch it down to 8 before
saving. Another alternative is to do a linear conversion with DCRAW
command line freeware converter. You'll need to use the correct wide
gamut color profile but I think this comes close to preserving the most
information if you plan to make adjustments.
Anonymous
March 31, 2005 5:53:20 PM

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

An 8 MegaPixel camera with a 12-bit A/D creates 12 MBytes of data.
This gets losslessly compressed to 8 MBytes (huffman coding) as RAW

The RAW file contains only one color pixel for each sensor location. A
process known as demosaicing (or deBayering) creates RGB from the
singel location by interpolating surrounding pixels. There are about 22
different algorithms, each with advantages and disadvantages.

When you convert a RAW to 16-bit TIFF, the 8 MByte file expands to
12MBytes, is demosaiced into 36 MBytes and then each 12-bit pixel
is stored in a 16-bit container for a total of 48MBytes of size.

Mitch
Anonymous
March 31, 2005 6:13:32 PM

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

mike regish <mregish@comcast.net> wrote:
> I tried saving a RAW image as a tiff so I could play with it in PS5.5. I was
> surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
> the straight data from the ccd and that tif at least wouldn't compress it,
> but why is it so much bigger?
>
> Also, is there any advantage to working with the raw file as opposed to tif?
>
> mike regish
>

You should be able to save the TIFF file with LZW or ZIP (the latter is
not supported in all software) compression. Doing so will greatly
reduce the file size. If you save as a PSD file, you will see the same
expansion in file size. Do your work in a format that doesn't suffer
data loss with each save [i.e. .psd or .tiff] and then when you are
done, export the JPEG at quality level 10 and 300 dpi cropped to your
print size (i.e. 8x10"). If you don't perform the cropping yourself,
the printers software [or the human operator] will crop it for you and
you may not get what you actually wanted. Also, if you print to mass
printers like Walmart, Target, Walgreen's and Shutterfly or Ofoto, then
it would be wise to save the JPEG in their colorspace of sRGB as well.
If you use the better retailers like MPIX.com, you can leave the JPEG in
Adobe RGB (1998).


--
Thomas T. Veldhouse
Key Fingerprint: 2DB9 813F F510 82C2 E1AE 34D0 D69D 1EDC D5EC AED1
Spammers please contact me at renegade@veldy.net.
Anonymous
March 31, 2005 6:32:12 PM

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

"Sheldon" <sheldon@XXXXXXXXsopris.net> wrote in
news:npCdnVJFVaa04NbfRVn-jA@comcast.com:

> Okay, now I don't get it. Compression is compression. If you
> compress a file it has to come back to it's original size so you can
> see it.

Good so far.

> How does a RAW file act as a lossless compression without
> changing anything when you open and close it?

You don't "open and close" a RAW file. The act of "opening" a RAW file
creates a copy in an intermediate format which must be saved in something
besides RAW. Think of it as "reading" and not "opening."

> I thought a tiff file
> was "no" compression at all.

No, there are a number of compressions available for Tiff, some lossless,
some not. Generally, though, the idea is to use something that is
lossless for a working file.

> Does RAW have more to do with the file
> coming straight from the camera with little or no changing of the file
> in the camera, regardless of settings?

NOTHING changes in the camera in a RAW file. It is the RAW data right off
the sensor, no post processing. RAW processor software such as C1 or ACR
does the job.

There are, unfortunately, some RAW formats (i.e., particular camera
bodies) that actually use lossy compression, which are the sole exception
to the above statement. I believe either the marketing department or R &
D for those companies are smoking crack.
Anonymous
April 1, 2005 12:46:24 AM

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

"Jim Townsend" <not@real.address> wrote in message
news:114mrgufoq1v9aa@news.supernews.com...
> mike regish wrote:
>
> > I'm using the Dimage Viewer software that came with the Minolta 7D. It
has 2
> > choices for saving as tif-24 and 48 bit. The 48 bit was clicked when I
> > opened it. Is this the same thing you're referring to?
>
> Yes..
>
> 8 bit refers to how many bits in a single color. There are
> three primary colors so the total is 8 x 3 = 24 bits.
>
> With 48 bit you have 48 / 3 = 16 bits per color.
>
> (Just another confusing thing :-)
>
>

Let's go the extra mile here and mention that 24-bit then equates to 2^24
power or 16,777,216 color combinations whereas the 48-bit gives you a
whopping 281,474,976,710,656 shades of color!!! Nearly 300 trillion colors.
Hmmm, I wonder what kind of monitor I should get for that? : )

Ron
Anonymous
April 1, 2005 2:48:32 AM

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

On Thu, 31 Mar 2005 06:13:32 -0800, Thomas T. Veldhouse wrote
(in article <424c058c$0$193$8046368a@newsreader.iphouse.net>):

> mike regish <mregish@comcast.net> wrote:
>> I tried saving a RAW image as a tiff so I could play with it in PS5.5. I
>> was
>> surprised to see the file size jump from 8 meg to 35 meg. I figured raw was
>> the straight data from the ccd and that tif at least wouldn't compress it,
>> but why is it so much bigger?
>>
>> Also, is there any advantage to working with the raw file as opposed to tif?
>>
>> mike regish
>>
>
> You should be able to save the TIFF file with LZW or ZIP (the latter is
> not supported in all software) compression. Doing so will greatly
> reduce the file size. If you save as a PSD file, you will see the same
> expansion in file size. Do your work in a format that doesn't suffer
> data loss with each save [i.e. .psd or .tiff] and then when you are
> done, export the JPEG at quality level 10 and 300 dpi cropped to your
> print size (i.e. 8x10"). If you don't perform the cropping yourself,
> the printers software [or the human operator] will crop it for you and
> you may not get what you actually wanted. Also, if you print to mass
> printers like Walmart, Target, Walgreen's and Shutterfly or Ofoto, then
> it would be wise to save the JPEG in their colorspace of sRGB as well.
> If you use the better retailers like MPIX.com, you can leave the JPEG in
> Adobe RGB (1998).
>
>
>

According to Mpix website: "Mpix printers output in sRGB color space"

http://www.mpix.com/help.aspx?

Click FAQs

Click What Color Space Does Mpix Accept
!