Disconnect Between HD File Size & PS's File Size

I don't think this group is just about the capture side of digital
photography (cameras, etc.). I think it's also about working with
images after capture, so that's why I submit the following.

I scanned a 6x6 cm. film chrome @ 3200 ppi, @16-bit depth, as a raw
image file. Of course, the file size is huge: 269.4 MB. My Mac G5 w/
2.5 GB of RAM handles it ok. I use Photoshop CS (Ver. 8.) I'm just
giving some background to reduce irrelevant questions or comments.
Actual file size is irrelevant to my question.

Now. There's no discrepancy between the raw image's file size on the
HD & what PS shows in Image Size. That's OK.

The problem is with the master image file I created from this raw
file. My HD info shows the master file to be 433.6 MB, but PSImage
Size shows it to be 185.8 MB. No layers, etc., are involved. I notice
that if I multiply 185.8 by 3 (the three RGB channels), I get close to
the 433.6 MB that is in the HD file.

I don't understand what's going on. Why is my raw file size the same
on the HD & in PS, while the master image file is 3X larger on the HD
than in PS? Why is there no problem with one file, but there is with
another? I did a Save As on the raw file before cropping & editing, so
I didn't do anything to the raw file. So, with the cropping, at least,
the master file should be *smaller* not *larger* than the raw file.

Can anyone help me? If you need more info, let me know, as I need
accurate info from my HD window prior to working on my images. I'm
very uncomfortable with this discrepancy. There should be agreement
between what my HD tells me & what PS tells me.

On Sun, 09 Sep 2007 10:13:48 -0700, One4All wrote:

I don't think this group is just about the capture side of digital
photography (cameras, etc.). I think it's also about working with
images after capture, so that's why I submit the following.

I scanned a 6x6 cm. film chrome @ 3200 ppi, @16-bit depth, as a raw
image file. Of course, the file size is huge: 269.4 MB. My Mac G5 w/
2.5 GB of RAM handles it ok. I use Photoshop CS (Ver. 8.) I'm just
giving some background to reduce irrelevant questions or comments.
Actual file size is irrelevant to my question.

Now. There's no discrepancy between the raw image's file size on the
HD & what PS shows in Image Size. That's OK.

The problem is with the master image file I created from this raw
file. My HD info shows the master file to be 433.6 MB, but PSImage
Size shows it to be 185.8 MB. No layers, etc., are involved. I notice
that if I multiply 185.8 by 3 (the three RGB channels), I get close to
the 433.6 MB that is in the HD file.

I don't understand what's going on. Why is my raw file size the same
on the HD & in PS, while the master image file is 3X larger on the HD
than in PS? Why is there no problem with one file, but there is with
another? I did a Save As on the raw file before cropping & editing, so
I didn't do anything to the raw file. So, with the cropping, at least,
the master file should be *smaller* not *larger* than the raw file.

Can anyone help me? If you need more info, let me know, as I need
accurate info from my HD window prior to working on my images. I'm
very uncomfortable with this discrepancy. There should be agreement
between what my HD tells me & what PS tells me.

This could be one of the many thousands of computational errors built-into
PhotoShop due to its 16-bit math foundation. This limitation harkens way back to
the mid 1990's and they've never changed it nor will they, PhotoShop is clearly
and has always been last-century technology. I would suggest trying to find a
better 32-bit editor, like PhotoLine 32 for the Mac. See if it reports the
correct sizes. Don't worry about it not reading your RAW files, it uses a method
that can read virtually all RAW file formats in existence, and some that are
even undocumented-- special purpose RAW data formats used for scientific
research purposes. Just be sure to set your work-space's default gamma in the
setup options for RAW files to 1.70 for Macs before importing a RAW file. Then
it imports them all just fine with the proper levels.

On Sep 9, 2:59 pm, AnswerMan wrote:

This could be one of the many thousands of computational errors built-into
PhotoShop due to its 16-bit math foundation. This limitation harkens way back to
the mid 1990's and they've never changed it nor will they, PhotoShop is clearly
and has always been last-century technology. I would suggest trying to find a
better 32-bit editor, like PhotoLine 32 for the Mac. See if it reports the
correct sizes. Don't worry about it not reading your RAW files, it uses a method
that can read virtually all RAW file formats in existence, and some that are
even undocumented-- special purpose RAW data formats used for scientific
research purposes. Just be sure to set your work-space's default gamma in the
setup options for RAW files to 1.70 for Macs before importing a RAW file. Then
it imports them all just fine with the proper levels.

The raw file I refer to is not the RAW file recorded by a digital
camera. I call it a raw file to distinguish it from the files I've
edited, based on it. It's the file that I scanned at max. optical
resolution and bit depth of the scanner, without any scanner color,
etc., modification. It's a standard TIFF file.

Thank you for suggesting an alternative image editor.

In article .com,
One4All wrote:

[...] My HD info shows the master file to be 433.6 MB, but PSImage
Size shows it to be 185.8 MB.

The Image Size dialog that you get when you choose "Image Size" from
the "Image" menu shows the size in *pixels*, not *bytes*. In PS CS2
it reads e.g. "Pixel Dimensions: 2.00M" (not MB!).

I notice
that if I multiply 185.8 by 3 (the three RGB channels), I get close to
the 433.6 MB that is in the HD file.

That's what I would expect for an uncompressed TIFF file that has 8 bits
(1 byte) per RGB color channel: 3 bytes per pixel.

--
Jon Bell Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA

Besides the likelihood that your file size is too big for practical use:
What do you mean by master file?
A pdf file usually balloons up depending on layers and other things.
You also may have converted one file to a higher color bit depth, like 8 to
16, hence the trebling of size?

On Sep 9, 3:33 pm, Marty Fremen wrote:
One4All wrote:
The problem is with the master image file I created from this raw
file. My HD info shows the master file to be 433.6 MB, but PSImage
Size shows it to be 185.8 MB. No layers, etc., are involved. I notice
that if I multiply 185.8 by 3 (the three RGB channels), I get close to
the 433.6 MB that is in the HD file.

What is the file type of this master image file? It may be that it contains
data other than just the image.

As I told AnswerMan, it's a standard TIFF file. It was scanned from a
6x6 cm. chrome (slide), at max. resolution and bit depth of the
scanner. I call it raw, but it's not the RAW format that comes from a
digital camera. There is no data other than the image.

It wasn't clear to me from what you said whether the master image file had
been cropped so I'm not sure what to make of the difference between it and
the raw. If you have cropped the image then this may account for the 185MB
reported v. 269MB raw.

Wait a minute. I'm talking about the master image discrepancy, not the
raw, or original image discrepancy, because there is no discrepancy
there. Reread my post. It's the master that's the problem.

As a general point, I don't think it's worth worrying about file sizes in
MB except as concerns having enough disk space, and uncompressed image size
in MB as shown by photoshop has absolutely no use at all IMHO. Although
labs often talk about images which open out to such-and-such a number of
megabytes, I've never found such information in any way useful or relevent
and I don't know anyone outside of processing lab brochures who talks about
images in terms of their uncompressed bitmap size. All it tells you is how
big the file would be if you saved it as an uncompressed bitmap, which is a
file format that almost no-one uses.

I'm not following you. In another thread in
http://groups.google.com/group/comp....s/topics?hl=en, a
post told me resolution is not that big a deal for Epson printers, so
I guess file size and resolution are irrelevant, anymore? :-) There
has to be some standard, or nearly so, to achieve an acceptable print
at a given size from a given file size at a given resolution. As
usual, I'm behind the technology.

The important data about an image is the height & width in pixels,

There, you have me. H & W in pixels means nothing to me (or it hasn't,
until now) because I've been a film photographer all my life. Somehow,
I've got to translate pixel dimensions in my head into print (inches)
dimensions, which I've asked about in a separate thread in this
newsgroup. I just can't project a x b pixel dimensions to 8 x 10, 11 x
14, etc., print sizes.I just bought a Pentax K10d camera & hopefully
I'll start getting my head around this new way of talking about image
sizes.

I must also tell you that I am not formatting my images for computer
viewing or just 4x6 snapshot prints. I'm looking at formatting images
for 11x14 or greater print output. File size, resolution, and print
size have to figure in there.

Thanks.

On Sep 9, 9:14 pm, "flambe" wrote:
Besides the likelihood that your file size is too big for practical use:
What do you mean by master file?

"Practical use" is a relative term. The use you may have for a file
can be far different than the use I may have. Let's just say, with the
large file, my options are open. RAM and disk space are irrelevant for
me. If I need more of either, I'll buy more, because they are cheap
compared to my need.

By master file, I mean the edited file generated from the original
file that was scanned. The master file is what will generate all other
uses of the image. I erroneously called the original file a raw file,
which confused some people, who thought I was talking about the RAW
format in a digital camera.

A pdf file usually balloons up depending on layers and other things.
You also may have converted one file to a higher color bit depth, like 8 to
16, hence the trebling of size?

There are no layers, etc., in the master file. I checked for that, but
you may have a point. Like I said, I cropped the original image to
produce the master image, which should have resulted in a smaller file
size. But, the file shows on my HD as an "Adobe Photoshop TIFF file."
The original shows as a "TIFF document." I don't think the Adobe TIFF
file is a .pdf file. Am I wrong?

I did not upsample the original from 8-bit to 16-bit. Both the
original and the master files are in 16-bit. BTW, 8-bit to 16-bit is
double, not triple, the file size.

Just want to let you all know I solved my "problem." I checked the
Layers palette more closely & saw there was a Histogram (Adjustment?)
Layer in addition to the Background Layer. I flattened the image, did
a Save, and Voila! The HD file size and PS's file size are identical.
It's surprising how much a single Layer can add to an image's file
size.