Scanning 4x5 on epson 4870 at 16-bits/channel

Hi
I bought an epson 4870 scanner today for the purpose
of scanning 4x5 fuji velvia. I have done many tests
and I am very satisfied with the results, scanning at
4800 ppi and 48-bits, then downsizing to 3200 ppi but
keeping the 16 bits for processing. I can pull a lot
of nice detail out of the shadows if I want with the 16-bit.
Results are similar to drum scans I've done.

So now I'm ready to scan a full size 4x5 sheet.
4.67 x 3.70 inches at 4800 ppi, 48-bit:
I get the error
"Selected area is too large for this resolution"

Same at 3200, 48-bit. Only when I go down to 3200 ppi and 24-bit
can I scan a full size 4x5.

I'm running a 1.8 GHz win xp box with 1 GByte of ram.

I get the same results if I run as a plugin to photoshop cs or
as epson scan standalone.

Has anyone had/solved this problem? If you successfully scan
full size 4x5 at 4800 ppi and 48-bit, what kind of setup do you have?

Thanks,
Roger Clark

On Tue, 18 May 2004 20:15:41 -0600, "Roger N. Clark (change username
to rnclark)" wrote:


Has anyone had/solved this problem? If you successfully scan
full size 4x5 at 4800 ppi and 48-bit, what kind of setup do you have?


Have you considered the memory and bandwidth
limitations of what you're attempting?

4800 dpi is 23 million pixels per square inch.
Times 20 square inches is 460 million pixels.

That's 1.38 gigabytes at 24 bit color, 2.76 Gb
at 48-bit. That 2.76 G image will take 5 minutes
to move off the scanner and onto your PC or
Mac at 9.2 Mbytes/s.

FWIW, I'm scanning 4x5 at 2500 dpi and
those 330 Mbyte files are killing me G.


rafe b.
http://www.terrapinphoto.com

In article ,
says...
On Tue, 18 May 2004 20:15:41 -0600, "Roger N. Clark (change username
to rnclark)" wrote:


Has anyone had/solved this problem? If you successfully scan
full size 4x5 at 4800 ppi and 48-bit, what kind of setup do you have?


Have you considered the memory and bandwidth
limitations of what you're attempting?

4800 dpi is 23 million pixels per square inch.
Times 20 square inches is 460 million pixels.

.... 2.76 Gb at 48-bit.

Which can't even be saved in most imaging programs.
Photoshop can't handle over 2GB PSD or TIFF.
The CS version can, but only in a proprietary file format, not PSD or
TIFF.

And no, saving as JPEG won't help at any compression rate either, as has
to open at full pixel dimensions/filesize in Photoshop, ala TIFF.


Mac

In article ,
says...
In article ,
says...
On Tue, 18 May 2004 20:15:41 -0600, "Roger N. Clark (change username
to rnclark)" wrote:


Has anyone had/solved this problem? If you successfully scan
full size 4x5 at 4800 ppi and 48-bit, what kind of setup do you have?


Have you considered the memory and bandwidth
limitations of what you're attempting?

4800 dpi is 23 million pixels per square inch.
Times 20 square inches is 460 million pixels.

.... 2.76 Gb at 48-bit.

Which can't even be saved in most imaging programs.
Photoshop can't handle over 2GB PSD or TIFF.
The CS version can, but only in a proprietary file format, not PSD or
TIFF.

And no, saving as JPEG won't help at any compression rate either, as has
to open at full pixel dimensions/filesize in Photoshop, ala TIFF.


Mac

Let me rephrase that slightly....what happens is, Photoshop will
generally be able to SAVE the 2GB image. It just won't re-open it

M

Roger N. Clark (change username to rnclark) wrote:
Hi
I bought an epson 4870 scanner today for the purpose
of scanning 4x5 fuji velvia. I have done many tests
and I am very satisfied with the results, scanning at
4800 ppi and 48-bits, then downsizing to 3200 ppi but
keeping the 16 bits for processing. I can pull a lot
of nice detail out of the shadows if I want with the 16-bit.
Results are similar to drum scans I've done.

So now I'm ready to scan a full size 4x5 sheet.
4.67 x 3.70 inches at 4800 ppi, 48-bit:
I get the error
"Selected area is too large for this resolution"

Same at 3200, 48-bit. Only when I go down to 3200 ppi and 24-bit
can I scan a full size 4x5.

I'm running a 1.8 GHz win xp box with 1 GByte of ram.

I get the same results if I run as a plugin to photoshop cs or
as epson scan standalone.

Has anyone had/solved this problem? If you successfully scan
full size 4x5 at 4800 ppi and 48-bit, what kind of setup do you have?

Thanks,
Roger Clark


This just came up in the photo.net digital darkroom forun. See
http://www.photo.net/bboard/q-and-a-...?msg_id=008ICU

See Doug Fisher's response. It seems that it won't work at 4800 ppi if
you have digital ICE turned on. But it should work if you turn it off.
It seems to be a problem with the software. So it might work fine with
Vuescan.

By the way, I regularly scan 4 x 5 with and Epson 3200 at 16 bits per
channel using Vuescan.

"Roger N. Clark (change username to rnclark)"
wrote in SNIP
So now I'm ready to scan a full size 4x5 sheet.
4.67 x 3.70 inches at 4800 ppi, 48-bit:
I get the error
"Selected area is too large for this resolution"

I'm not too suprised at this a scan of 4.67" X 3.7" at 4800 ppi and
16bits per channel results in a scan size of about 2.39 Gbytes!

You will need to scan at a lower resolution for this size of scan,
especially at 16 bits.

Steve.

In article ,
Mac McDougald wrote:

Which can't even be saved in most imaging programs.
Photoshop can't handle over 2GB PSD or TIFF.
The CS version can, but only in a proprietary file format, not PSD or
TIFF.

Does VueScan handle 2gig files?

"Steve" wrote:
"Roger N. Clark (change username to rnclark)"
wrote in SNIP
So now I'm ready to scan a full size 4x5 sheet.
4.67 x 3.70 inches at 4800 ppi, 48-bit:
I get the error
"Selected area is too large for this resolution"

I'm not too suprised at this a scan of 4.67" X 3.7" at 4800 ppi and
16bits per channel results in a scan size of about 2.39 Gbytes!

You will need to scan at a lower resolution for this size of scan,
especially at 16 bits.

Or you can scan in sections that overlap, process each section identically,
and then stitch together in Photoshop after you've downsampled to a more
sensible resolution.

You should be able to downsample to 3000 dpi with no loss of information
(since someone here reported 30 lp/mm in one direction and 40 lp/mm in the
other, and 40 lp/mm is (assume 3 pixels per line pair) 40x3x25.4 = 3048).

IMHO, even 2700 dpi would be fine, but 3050 is safe.

4x5 at 3050 dpi = 180MP
4x5 at 2700 dpi = 146MP
3.7x4.7 at 2700 dpi = 127MP

You'll want 2GB of RAM to handle those files, but at least it's possible.

David J. Littleboy
Tokyo, Japan

"Chris Brown" wrote:
Does VueScan handle 2gig files?

I don't think so, but I've never tested this. It depends
on the inner workings of the TIFF library I'm using, and
I haven't tested this.

Regards,
Ed Hamrick

This is a programming restriction because the EPSON Scan transfers RGB
information in one go rather than individually (probably a Twain
requirement). There is normally a limitation of 74Kb of data per line
of scanned data that can be transferred (hardware limitation).

For example:

At 48bit colour 1 pixel = 6 bytes.

At 4800 dpi and 48 bit colour the maximum width of scan will be 2.6
inches.

Max scan width in bytes (74 x 1024)
----------------------------------- = Maximum width of scan
Scan resolution in bytes (dpi x 6)

75766 (74 x 1024)
----------------- = 2.6 inches
28800 (4800 x 6)

The 10,925 pixel limit is the same though this works out to a maximum
scan line of 64Kb for both 48 and 24 bit colour:

10925 at 48 bit colour = 65.550 bytes (64Kb)

21845 at 24 bit colour = 65.535 bytes (64Kb)

This is odd as I would have expected a maximum scan line of 12,627
pixels for 48 bit colour and 25,255 pixels in 24 bit colour. But it
may be that there is a limitation of 64Kb per scan line for the
Perfection 4870.



(Steve) wrote in message . com...
"Roger N. Clark (change username to rnclark)"
wrote in SNIP
So now I'm ready to scan a full size 4x5 sheet.
4.67 x 3.70 inches at 4800 ppi, 48-bit:
I get the error
"Selected area is too large for this resolution"

I'm not too suprised at this a scan of 4.67" X 3.7" at 4800 ppi and
16bits per channel results in a scan size of about 2.39 Gbytes!

You will need to scan at a lower resolution for this size of scan,
especially at 16 bits.

Steve.