Questions on film scanning, TIF files

[photoguy_222]

Dear Experts,

Recently, I bought a Nikon coolscan 5000, and
did some scanning of some 35mm transparencies and negs.

I scanned at 16 Bit, used Digital ICE, and saved
in TIF format.

Interestingly, the file sizes were 137 megs big!

I thought that this was odd, because the size of the
images themselves were: 3946 x 5959 pixels,
which, if you multiply these, is about 23 megs.

If I scan at 8 bit, it about 1/2 the size.

Why is the TIF file almost 6 times the size of
the image size? What other information
is being stored in TIF?

What are the advantages of TIF format?


Thanks a lot

(Note: I'm really NOT asking how to get smaller file sizes.)

 

[Toni Nikkanen]

I thought that this was odd, because the size of the
images themselves were: 3946 x 5959 pixels,
which, if you multiply these, is about 23 megs.

This is because it's 16 bits per colour channel, which means every RGB
color pixel is made of 3*16 = 48 bits, which happens to be 6 bytes. If
you scanned monochrome you would be looking at 46 megabyte pictures..

 

[Mike Russell]

Dear Experts, ....
I scanned at 16 Bit, used Digital ICE, and saved
in TIF format.

Interestingly, the file sizes were 137 megs big!

I thought that this was odd, because the size of the
images themselves were: 3946 x 5959 pixels,
which, if you multiply these, is about 23 megs.

In this situation, multiply by a factor of 6 bytes per pixel to convert
megapixels to megabytes: a factor of 3 for each of the red, green, and blue
channels, and a factor of 2 for 16 bit mode.

 

[jeremy]

In this situation, multiply by a factor of 6 bytes per pixel to convert
megapixels to megabytes: a factor of 3 for each of the red, green, and
blue channels, and a factor of 2 for 16 bit mode.
--

How many bytes-per-pixel are digital cameras? My own scanner (3600x3600
ppi) produces 16-bit files of about 103 meg--much larger than even the
highest-resolution digital camera.

 

[Noons]

How many bytes-per-pixel are digital cameras? My own scanner (3600x3600
ppi) produces 16-bit files of about 103 meg--much larger than even the
highest-resolution digital camera.

digital cameras mostly store the images in jpg files, which apply lossy

compression to the data. Hence the much smaller files. If you use the

so-called RAW mode in a digital camera, then you end up with similar
sized
files to what you get with a scanner.

you can go both ways: save scanner output as jpg, in which case
you see a similar reduction in size.

All sorts of theories and ideas on why it should or should not be done
one
way or the other.

In very general terms: if you want to keep a pristine copy of the
scanner output or
digital camera capture for further post-processing, then use TIFF or
RAW to keep
the image, respectively.

If you don't plan to do any further post-procesing, then jpg is
perfectly fine and
will result in much less disk space being used.

You may also use jpg as the output of any post-processing from TIFF or
RAW.

HTH

 

[Dances With Crows]

[ Excessive crossposting trimmed ]
["Followup-To:" header set to comp.periphs.scanners.]

I scanned at 16 Bit, used Digital ICE, and saved in TIF format. The
[files] were 137 megs! The images themselves were 3946 x 5959 pixels,
which, if you multiply these, is about 23 megs. If I scan at 8 bit,
it about 1/2 the size.

Why is the TIF file almost 6 times the size of the image size?

3946 pixels wide * 5959 pixels high * 6 bytes/pixel (16 bits/channel, R,
G, B channels)= 134M uncompressed. If you save with LZW compression,
you might reduce the size of the images to ~70M, depending on lots of
factors. Whether the software you're using can save things in LZW is
anyone's guess.

What other information is being stored in TIF? What are the
advantages of TIF format?

TIFF files can store a lot of essentially arbitrary data in tags, which
are defined in great detail in the TIFF format specs. Every
TIFF-writing app generally defines Image Length, Image Width, Resolution
(dpi or dpcm), Compression, and Bits/Sample. A bunch of other less
frequently-used tags like Color Profile have been defined by SGI and the
libtiff guys, and there are some apps (like TypeReader 6) that store
app-specific info in TIFF tags that are not officially defined.

For advantages, it's mostly about the tags and platform independence.
Many of the things stored in the tags are important in various types of
image processing, and the structure of TIFF means the tags aren't going
to get lost (as could happen with other ways of encoding that data).
TIFF can also store multiple images in 1 file ("multipage TIFF") which
can be useful in certain circumstances.

libtiff provides a uniform way to get at the raw bitmap(s) and tag info,
no matter what OS or arch you're using, so TIFF is essentially
future-proof. Images stored in formats that aren't Open[0] are going to
be difficult to read when the commercial software provider you're using
decides that Format 0.1 is obsolete and that you have to give them $ for
the privilege of reading your data. This is why a lot of people store
archival copies of images in TIFF. HTH,

[0] JPEG, PNG, and TIFF are open, BMP and GIF are well-understood if not
technically completely open.

 

[ray]

Dear Experts,

Recently, I bought a Nikon coolscan 5000, and
did some scanning of some 35mm transparencies and negs.

I scanned at 16 Bit, used Digital ICE, and saved
in TIF format.

Interestingly, the file sizes were 137 megs big!

I thought that this was odd, because the size of the
images themselves were: 3946 x 5959 pixels,
which, if you multiply these, is about 23 megs.

If I scan at 8 bit, it about 1/2 the size.

Why is the TIF file almost 6 times the size of
the image size? What other information
is being stored in TIF?

Mainly because you specified a 16 bit tif. 16 bits is two bytes of
information for each channel R, G, B: 2 times three is six - ergo size is
six times the total number of pixels.

What are the advantages of TIF format?

No loss of information.

 

[ray]

How many bytes-per-pixel are digital cameras? My own scanner (3600x3600
ppi) produces 16-bit files of about 103 meg--much larger than even the
highest-resolution digital camera.

My calculations show 3600x3600x6 = 77mb. Assuming 16 bits for each color
channel. I can't see how you get 103mb, unless you're using a format which
might include a 16 bit alpha channel, as well.

 

[Scott W]

My calculations show 3600x3600x6 = 77mb. Assuming 16 bits for each color
channel. I can't see how you get 103mb, unless you're using a format which
might include a 16 bit alpha channel, as well.

He said 3600 ppi, not 3600 pixels, I come out with 104,136,400 for a
full frame scan at 3600 ppi
and 16 bits / color.

Of course he better then the hightest-resolution digital camera is a
bit off.

Scott

 

[ray]

He said 3600 ppi, not 3600 pixels, I come out with 104,136,400 for a
full frame scan at 3600 ppi
and 16 bits / color.

Of course he better then the hightest-resolution digital camera is a
bit off.

Scott

You're right, of course. In which case the size of the file is related to
the size of the image.

 

[Barry Watzman]

Others have already explained how you got a 137 megabyte file.

Yes, JPEG is "lossy compression", but just a tiny bit of compression ...
which you will NEVER be able to detect, at all, in any way ... will
produce a HUGE reduction in file size (as much as 90%) while retaining
both the resolution and color depth.

This size (137 MB) is a problem as many of us have thousands of photos.
The fact is that with a file size of 1/10 of what you have, you can do
anything that you are ever likely to want to do.

 

[Papa Joe]

Others have already explained how you got a 137 megabyte file.

Yes, JPEG is "lossy compression", but just a tiny bit of compression
... which you will NEVER be able to detect, at all, in any way ... will
produce a HUGE reduction in file size (as much as 90%) while retaining
both the resolution and color depth.

This size (137 MB) is a problem as many of us have thousands of photos.
The fact is that with a file size of 1/10 of what you have, you can
do anything that you are ever likely to want to do.

Any professional digital photographer that sends JPG to any sort of Ad
Agency or design firm for color correction and then print on Magazine,
billboard or litho press jobs, should be shot and hung. We need way
more information to edit the photos and manipulate them than to print
them with decent results. Look at your histogram in photoshop and see
for yourself. It's called combing and JPG is by far inferior to TIF or
raw. The JPG compression strips out pixels... even at 10 setting (max).
It destroys valuable information for proper color correcting and must
be stopped!!!

JPG should be used only for family portrait studios and amateurs that
can't afford space, but in the pro world, JPG is shunned. Very much
disliked and you will lose respect among the adverstising world.

 

[KatWoman]

Any professional digital photographer that sends JPG to any sort of Ad
Agency or design firm for color correction and then print on Magazine,
billboard or litho press jobs, should be shot and hung. We need way more
information to edit the photos and manipulate them than to print them with
decent results. Look at your histogram in photoshop and see for yourself.
It's called combing and JPG is by far inferior to TIF or raw. The JPG
compression strips out pixels... even at 10 setting (max). It destroys
valuable information for proper color correcting and must be stopped!!!

JPG should be used only for family portrait studios and amateurs that
can't afford space, but in the pro world, JPG is shunned. Very much
disliked and you will lose respect among the adverstising world.

OK I have sent the same print job in both tiff and jpeg formats
with no visible differences in reproduction
In most cases the print house asks specifically for a jpg at 300 res in CMYK
and to size of print (for CD covers and labels, did one poster, many
postcards and business cards this way)

As I have always felt this format unsuitable for preparing printwork, as you
do, I always save my jobs in TIFF- flattened not compressed. (I save all my
layers in PSD in case of changes)
I also hear that all text type should not be flattened into the work in PS
but to use Illy or In Design would be better to keep vectored text. But no,
they do not want that!!
are you a printer Joe?
Maybe that is only cheap print jobs? you would consider sub-standard?

I felt that the TIFF was superior and was surprised they did not care to use
it
I make sure to encode the icc in my jpg now
and use maximum not jpg high
the file size is not really any smaller than the TIFF
so it does not save any ftp time
most do not want to wait for a CD to arrive by mail with larger editable
files as PSD.
I have rarely sent a print job that does not need adjustments to type or
color etc.so it really does not save any time for me to change it and re
save and re send it

as for the advertising world well most art directors know squat about
formats of photos, or how to color-correct them
sad but true
I would be happy if they left the final retouching to those who created the
pictures but they seem to prefer to upload the jpegs direct to their laptops
and go home and work on them same day. I would not dare give them RAW. Who
knows what they would do?

I can recall about 2-4 print jobs in 20 years I have ever been pleased with
in terms of good, respectful of the photo art direction and retouching done
well, with beautiful printing. In most cases I just sigh and think what a
waste of beautiful pictures. And I put my own prints from the shoot that I
like in the portfolio.

I find commercial clients care more about how much will this cost (more like
how cheap)
and how fast can you shoot and deliver
of course the poor AD and CD's have to get approval on their work from a
business group with zero knowledge of graphic design who always pick the
worst images and want a bunch of tacky text and blurbs all over the place,
or worse make cutouts of everything you shot and turn it into some tacky
collage.......

rant over

 

[Papa Joe]

OK I have sent the same print job in both tiff and jpeg formats
with no visible differences in reproduction
In most cases the print house asks specifically for a jpg at 300 res in CMYK
and to size of print (for CD covers and labels, did one poster, many
postcards and business cards this way)

As I have always felt this format unsuitable for preparing printwork, as you
do, I always save my jobs in TIFF- flattened not compressed. (I save all my
layers in PSD in case of changes)
I also hear that all text type should not be flattened into the work in PS
but to use Illy or In Design would be better to keep vectored text. But no,
they do not want that!!
are you a printer Joe?
Maybe that is only cheap print jobs? you would consider sub-standard?

I felt that the TIFF was superior and was surprised they did not care to use
it
I make sure to encode the icc in my jpg now
and use maximum not jpg high
the file size is not really any smaller than the TIFF
so it does not save any ftp time
most do not want to wait for a CD to arrive by mail with larger editable
files as PSD.
I have rarely sent a print job that does not need adjustments to type or
color etc.so it really does not save any time for me to change it and re
save and re send it

as for the advertising world well most art directors know squat about
formats of photos, or how to color-correct them
sad but true
I would be happy if they left the final retouching to those who created the
pictures but they seem to prefer to upload the jpegs direct to their laptops
and go home and work on them same day. I would not dare give them RAW. Who
knows what they would do?

I can recall about 2-4 print jobs in 20 years I have ever been pleased with
in terms of good, respectful of the photo art direction and retouching done
well, with beautiful printing. In most cases I just sigh and think what a
waste of beautiful pictures. And I put my own prints from the shoot that I
like in the portfolio.

I find commercial clients care more about how much will this cost (more like
how cheap)
and how fast can you shoot and deliver
of course the poor AD and CD's have to get approval on their work from a
business group with zero knowledge of graphic design who always pick the
worst images and want a bunch of tacky text and blurbs all over the place,
or worse make cutouts of everything you shot and turn it into some tacky
collage.......

rant over

I'm a freelance designer that does lots of photo editing for national
magazines,
tousist guides, billboards and newsprint.

JPG has been throw in my world for only one obvious reason...
Small file size that allows clients and photographers to send files via
internet.
it has little value sendind one to press. Today there are DTP presses
that have better quality output than printers had in the 80's , but in
the 80's they used better images. It doesn't make any sense for
quality. We have better printers but we send nasty JPG's to the
press... The only thing JPG does, is make it easy for the client to
store and to send quickly... and they can see it on their monitor...
they love JPG!
BleH!!!