optimum resolution for repairing old B&W photos?

Hi

I'm wondering if Ive been overambitious and scanned at a res that is totally
unnecessary.

Ive ran into a few unexpected problems when trying to print some old photos
Ive restored.

Its seems that my system cant cope with the high res (2400dpi) scans Ive
made as I get numerous low memory erros - yet I have 1Gb of RAM!

Ive been working in Corel Photopaint.

The photopaint file is 153Mb. The jpg version of the same image (without
compression) is 108Mb.

When trying to see a print preview on screen, my system seems to grind to a
halt as I have to wait an age for anything to happen. (I have an AMD 3000XP)
Often I have to shut everything down and start again.

Using other imaging software I get the same probs. Even trying to paste a
link into DTP apps I get messages that the file is too big.

The only way I have been able to get around this is to reduce the picure res
from 2400 to 1200dpi.

I'm really surprised. Whats the point of having the option of a scanning res
of 9600dpi or more if the system falls over at 2400!

Do I really need to use 2400??

Thanks for any info.

Ian

In article ,
says...
Hi

I'm wondering if Ive been overambitious and scanned at a res that is totally
unnecessary.

Ive ran into a few unexpected problems when trying to print some old photos
Ive restored.

Its seems that my system cant cope with the high res (2400dpi) scans Ive
made as I get numerous low memory erros - yet I have 1Gb of RAM!

Ive been working in Corel Photopaint.

The photopaint file is 153Mb. The jpg version of the same image (without
compression) is 108Mb.


Do I really need to use 2400??

Thanks for any info.

Ian
There is no reason to scan at more than 300dpi (some would say 360) and
8 bit depth. The photos don't have more information in them to be
captured.
If they are snapshot sized and you want to go to a 2x enlargement you
can try 600dpi with a small loss of apparent sharpness. This can
sometimes be helped with a little unsharp mask in your photo editor.
Go to http://scantips.com for a good intro.
--
Robert D Feinman
Landscapes, Cityscapes and Panoramic Photographs
http://robertdfeinman.com
mail:

In article ,
says...
Hi

I'm wondering if Ive been overambitious and scanned at a res that is totally
unnecessary.

Ive ran into a few unexpected problems when trying to print some old photos
Ive restored.

Its seems that my system cant cope with the high res (2400dpi) scans Ive
made as I get numerous low memory erros - yet I have 1Gb of RAM!

Ive been working in Corel Photopaint.

The photopaint file is 153Mb. The jpg version of the same image (without
compression) is 108Mb.


Do I really need to use 2400??

Thanks for any info.

Ian
There is no reason to scan at more than 300dpi (some would say 360) and
8 bit depth. The photos don't have more information in them to be
captured.
If they are snapshot sized and you want to go to a 2x enlargement you
can try 600dpi with a small loss of apparent sharpness. This can
sometimes be helped with a little unsharp mask in your photo editor.
Go to http://scantips.com for a good intro.
--
Robert D Feinman
Landscapes, Cityscapes and Panoramic Photographs
http://robertdfeinman.com
mail:

"Ian Roberts" wrote in message
...

(snip)

Do I really need to use 2400??

Thanks for any info.

Ian

------------

You really need to understand that your printer will throw away anything
more than (generally) ca 300ppi data and go from there. Your print preview
is also trying to fit those large scans into a low res screen with the same
result and by the same method - discarding data. You are telling your comp
to put 10 pounds of s**t into a five pound bag. No wonder it takes ages to
do it.

As for large image files generally... try turning OFF the video
acceleration, but I emphasise that is NOT your problem here... it is your
bloated image files.

Journalist

"Ian Roberts" wrote in message
...

(snip)

Do I really need to use 2400??

Thanks for any info.

Ian

------------

You really need to understand that your printer will throw away anything
more than (generally) ca 300ppi data and go from there. Your print preview
is also trying to fit those large scans into a low res screen with the same
result and by the same method - discarding data. You are telling your comp
to put 10 pounds of s**t into a five pound bag. No wonder it takes ages to
do it.

As for large image files generally... try turning OFF the video
acceleration, but I emphasise that is NOT your problem here... it is your
bloated image files.

Journalist

"Robert Feinman" wrote in message
...
SNIP
There is no reason to scan at more than 300dpi (some would say
360) and 8 bit depth. The photos don't have more information in
them to be captured.

We have no way of knowing if the OP's original prints (may be contact
prints from large format glass plates for all we know) contain 300 or
more ppi of information. Since we can print and see the difference of
a modern inkjet print up to about 720 ppi, I would certainly scan at
at least 600 ppi.

What's more, if the full native resolution of the scanner's sensor is
not used, we effectively skip one or more sensels and scan lines
between the ones we do scan. That will introduce aliasing artifacts
that may or may not become noticeable in the final result (scanning
line art is e.g. more critical than anything else). The best strategy
would therefore be to scan at native resolution or at least at 1200
ppi, and then downsample (done properly by pre-filtering) to 600 or
1200 ppi. If the output must be enlarged versus the original, then the
enlargement factor should be additionally applied when scanning.

That kind of returns us to the OP's problem of memory error
difficulties when handling a 2400 ppi scan. I suggest checking the OS
settings and test the memory banks for faults.

Bart

"Robert Feinman" wrote in message
...
SNIP
There is no reason to scan at more than 300dpi (some would say
360) and 8 bit depth. The photos don't have more information in
them to be captured.

We have no way of knowing if the OP's original prints (may be contact
prints from large format glass plates for all we know) contain 300 or
more ppi of information. Since we can print and see the difference of
a modern inkjet print up to about 720 ppi, I would certainly scan at
at least 600 ppi.

What's more, if the full native resolution of the scanner's sensor is
not used, we effectively skip one or more sensels and scan lines
between the ones we do scan. That will introduce aliasing artifacts
that may or may not become noticeable in the final result (scanning
line art is e.g. more critical than anything else). The best strategy
would therefore be to scan at native resolution or at least at 1200
ppi, and then downsample (done properly by pre-filtering) to 600 or
1200 ppi. If the output must be enlarged versus the original, then the
enlargement factor should be additionally applied when scanning.

That kind of returns us to the OP's problem of memory error
difficulties when handling a 2400 ppi scan. I suggest checking the OS
settings and test the memory banks for faults.

Bart

I just want to make it clear that you don't scan at 300 ppi 100%. You scan
so that you will have 300ppi at the print size. If you scan a slide at 300
ppi 100% you get about what....500 pixels? If you want an 8x10 then you will
want to scan so that you have 3000 on the long side after you crop.


"Ian Roberts" wrote in message
...
Hi

I'm wondering if Ive been overambitious and scanned at a res that is
totally
unnecessary.

Ive ran into a few unexpected problems when trying to print some old
photos
Ive restored.

Its seems that my system cant cope with the high res (2400dpi) scans Ive
made as I get numerous low memory erros - yet I have 1Gb of RAM!

Ive been working in Corel Photopaint.

The photopaint file is 153Mb. The jpg version of the same image (without
compression) is 108Mb.

When trying to see a print preview on screen, my system seems to grind to
a
halt as I have to wait an age for anything to happen. (I have an AMD
3000XP)
Often I have to shut everything down and start again.

Using other imaging software I get the same probs. Even trying to paste a
link into DTP apps I get messages that the file is too big.

The only way I have been able to get around this is to reduce the picure
res
from 2400 to 1200dpi.

I'm really surprised. Whats the point of having the option of a scanning
res
of 9600dpi or more if the system falls over at 2400!

Do I really need to use 2400??

Thanks for any info.

Ian

I just want to make it clear that you don't scan at 300 ppi 100%. You scan
so that you will have 300ppi at the print size. If you scan a slide at 300
ppi 100% you get about what....500 pixels? If you want an 8x10 then you will
want to scan so that you have 3000 on the long side after you crop.


"Ian Roberts" wrote in message
...
Hi

I'm wondering if Ive been overambitious and scanned at a res that is
totally
unnecessary.

Ive ran into a few unexpected problems when trying to print some old
photos
Ive restored.

Its seems that my system cant cope with the high res (2400dpi) scans Ive
made as I get numerous low memory erros - yet I have 1Gb of RAM!

Ive been working in Corel Photopaint.

The photopaint file is 153Mb. The jpg version of the same image (without
compression) is 108Mb.

When trying to see a print preview on screen, my system seems to grind to
a
halt as I have to wait an age for anything to happen. (I have an AMD
3000XP)
Often I have to shut everything down and start again.

Using other imaging software I get the same probs. Even trying to paste a
link into DTP apps I get messages that the file is too big.

The only way I have been able to get around this is to reduce the picure
res
from 2400 to 1200dpi.

I'm really surprised. Whats the point of having the option of a scanning
res
of 9600dpi or more if the system falls over at 2400!

Do I really need to use 2400??

Thanks for any info.

Ian

On Mon, 30 Aug 2004 13:20:28 +0100, "Ian Roberts"
wrote:

Ive been working in Corel Photopaint.

I would suggest trying Adobe Photoshop.

I wouldn't touch Corel.

However, this may not be the problem, just a suggestion.


---Atreju---