Which dpi?

G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give better
quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

Currently I'm saving these as .bmp because .jpg is too lossy and thought
I'd change this via IrfanView or Picasa. Suggestions on this too
please? In the past I've just scanned a few photos, but this project is
archiving old and precious photos so I'd like the best reproduction
possible.

Once these have been scanned I'll burn them to DVD and it seems more and
more photos are coming out of the woodwork so I'm expecting this will be
an ongoing archival project.

Lastly......any suggestions where I might find an audio file to add to
the DVD? Motor racing/speedway soundtrack would be perfect! Couldn't
find anything by googling, possibly because I wasn't searching for the
correct name.

Thanks in advance for any suggestions
Bronwyn ;-)

In article , says...
G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give better
quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

In general, scanning at a higher dpi will give better results - albeit
at the expense of longer scanning times and larger files. It's a trade-
off which depends on how much time and storage you have - and what use
you want to make of the resulting files.

If you only envisage making same-as-original size prints, then scanning
at 300dpi will prove fine, IMHO.

However, if you wish to enlarge the prints, then scanning at a higher
resolution may well prove beneficial. A *lot*, however, depends on the
quality of the prints that you are scanning: they may not contain more
than 300dpi worth of detail. If they were taken on poor camera equipent,
with poor technique, or have sufferred due to the ravages of time, then
1200dpi may be wasted on them.

For best results, I suggest scanning a couple of representative prints
at 300dpi, 600dpi and 1200dpi, and then "using" each resultant scan in
the way that you envisage, be that an on-screen display, same-size print
or enlargement. Can you see any difference? Is the larger file size of
the higher-dpi files worth any visible difference? Is the difference
not obvious, but the added "security" of those extra pixels affordable
in terms of time and storage?

Currently I'm saving these as .bmp because .jpg is too lossy and thought
I'd change this via IrfanView or Picasa. Suggestions on this too
please? In the past I've just scanned a few photos, but this project is
archiving old and precious photos so I'd like the best reproduction
possible.

The "best possible" for your hardware is obviously 1200dpi ;-) Whether
or not it is worth it is another question altogether.

You may also wish to look at .tif file formats rather than .bmp for
archiving. There are non-lossy compression alogotithms available which
may help reduce file sizes for storage.

Once these have been scanned I'll burn them to DVD and it seems more and
more photos are coming out of the woodwork so I'm expecting this will be
an ongoing archival project.

If it is for archive...then I strongly suggest burning more than one DVD
and storing them in separate places. Then test each DVD periodically to
check it for deterioration. The long-term reliablity of recordable DVDs
is far from proven, IMHO.

Lastly......any suggestions where I might find an audio file to add to
the DVD? Motor racing/speedway soundtrack would be perfect! Couldn't
find anything by googling, possibly because I wasn't searching for the
correct name.

No idea. Sorry.

Ian
--
Ian Riches
Bedford, UK

assuming hard drive space is not an issue.....
scan as either 1200 or 600 dpi and save as COLOR TIFF files. TIFF are
more likely to be compatible in future years than bmp files.

You can "sepia tone" TIFF images if you wish, or you can do a MUCH
better job of making "grey" for the in between colors by separating
color layers in paintshop or photoshop or photoshop elements, and then
adjusting saturation.

Yes, I know you said BW photos - but the "grey" isn't really "pure
grey" in these prints any more - the paper has faded and yellowed,
etc, etc, even though you may not notice it. And at some point, you
will be asked to do (or will find some) color prints.....may as well
get accustomed to color scanning now.



HC wrote:
G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give better
quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

Currently I'm saving these as .bmp because .jpg is too lossy and thought
I'd change this via IrfanView or Picasa. Suggestions on this too
please?

"HC" wrote in message
...
G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that have
been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give better
quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?
The scanner dpi should depend on your intended use. There is little reason
at present and for the foreseeable future to print at more than 300 dpi.
Thus, to make same size prints, you only need 300 dpi scanns

Currently I'm saving these as .bmp because .jpg is too lossy and thought
I'd change this via IrfanView or Picasa. Suggestions on this too please?
In the past I've just scanned a few photos, but this project is archiving
old and precious photos so I'd like the best reproduction possible.
While jpg is a lossy compression technique, the amount of loss depends on
the amount of compression and the number of times that you edit the image.
I suggest that you use the least compression and that you only edit the
image once. It will be very hard for anyone to tell the difference between
the jpg files and the tiff files. Don't use bmp, that is a proprietory
Microsoft format.

Once these have been scanned I'll burn them to DVD and it seems more and
more photos are coming out of the woodwork so I'm expecting this will be
an ongoing archival project.
Save them to more than one medium. Some of these disks go bad without
warning. Manufacturers may also discontinue support for older formats as
well.
For example, my 35mm negative scans take 35 CDs, and I duplicated them on 4
DVDs. Certainly, I can rescan images if some evaporate, but the task is
quite tedious.
Do not use RW; these disks are not intended for long term storage.
Jim

Lastly......any suggestions where I might find an audio file to add to the
DVD? Motor racing/speedway soundtrack would be perfect! Couldn't find
anything by googling, possibly because I wasn't searching for the correct
name.

Thanks in advance for any suggestions
Bronwyn ;-)

On Mon, 05 Sep 2005 18:40:27 +1000, HC wrote:

G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give better
quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

Currently I'm saving these as .bmp because .jpg is too lossy and thought
I'd change this via IrfanView or Picasa. Suggestions on this too
please? In the past I've just scanned a few photos, but this project is
archiving old and precious photos so I'd like the best reproduction
possible.

Once these have been scanned I'll burn them to DVD and it seems more and
more photos are coming out of the woodwork so I'm expecting this will be
an ongoing archival project.

Lastly......any suggestions where I might find an audio file to add to
the DVD? Motor racing/speedway soundtrack would be perfect! Couldn't
find anything by googling, possibly because I wasn't searching for the
correct name.

Thanks in advance for any suggestions
Bronwyn ;-)

Hi, Bronwyn

Ian has already given you good advice about size. Personally, I'd go
for an equivalent of twice the size in case you want to make small
enlargements (printing is usually done as about 300dpi, so for twice
the size you need 600dpi). Above that you may find you get too many
artefacts.

Second, I can't emphasize enough how important it is for an archival
project to *never* use a lossy format (i.e. one that uses compression
resulting in lost detail) and to avoid formats that not widely used.
The best format for your images is TIFF. File size doesn't matter -
storage is cheap.

Finally, make more than one copy of the files and keep them in
different places and check the disks every six months or so to make
sure images still load. Regardless, resave to a new disk every three
years or so, and then to whatever new format is next after DVD. ;-)

--

Hecate - The Real One

Fashion: Buying things you don't need, with money
you don't have, to impress people you don't like...

In article , HC writes
G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with a
few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give
better quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

B&W prints will generally have more information on them than the
standard rule of thumb of 300ppi for corner shop colour prints, but
generally this isn't more than 600ppi. With the poor MTF of that
scanner at 1200ppi and the limited information on the prints above
600ppi, I doubt that scanning at 1200ppi can be justified on any
grounds.

Ideally you should scan at the limit of the equipment (in this case the
combination of the source material and the scanner probably sets that
around 600ppi) and archive this. Then resample to the optimum output
resolution for your final application using the best resampling
algorithm available to you.

Currently I'm saving these as .bmp because .jpg is too lossy and
thought I'd change this via IrfanView or Picasa. Suggestions on this
too please?

Save as Tiff with compression enabled: this is lossless compression
unlike jpeg - although the tiff specification permits jpeg compression,
few packages support it. Not only will you be able to save in less
space than .bmp format but, more importantly, you will be able to
archive your images with more bits per pixel, more dynamic range.

In the past I've just scanned a few photos, but this project is
archiving old and precious photos so I'd like the best reproduction
possible.

Best archive or best reproduction - they are not the same thing. Best
archive means saving more information that your existing equipment can
reproduce, because sometime in the future you will upgrade, and you
don't want to rescan everything all over again.

Thanks in advance for any suggestions
Bronwyn ;-)

Unusual name - only ever met one person called that before, they were
Australian too, but it sounds Welsh. ;-)
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

Thanks to all who replied with such detailed and helpful information!!

Larger file size is not a problem at the moment and as was mentioned
storage is cheap anyway. Time....well, there are never enough hours in
the day but I don't mind spending extra time waiting for higher scans
and better results. I've done a couple of tests at different dpi's and
could see a difference, so think I will continue with a higher dpi.

I don't even know what type of camera equipment was used to take the
originals but they have been fairly well kept in black-paged photo
albums and are in good condition although a couple which appear to have
been kept out of the album have yellowed with age, but still quite
acceptable. Another reason I think the higher dpi is a good idea, is
that I might never have access to these original photos again, they are
only on-loan to me until I can scan them, so the time spent now might be
a good investment in the future.

The suggestions about .tif sounds like a good idea too, thanks!

Jim...I never open my original photo files, they are stored on a
separate HDD (and backed up) and I play with a copy, so will do the same
with these photos.

Hecate...good idea to resave every few years, storage media changes
regularly too.

Kennedy...my name is Welsh, but I'm true-blue Aussie ;-)

Catfish...good point! I know some of my early photos are colour prints,
so expect some others will come out of the woodwork now I've started
this archiving project, which seems certain to become bigger than I
envisaged.

Again, thanks so much for all the help, it's truly appreciated! These
groups are such great ways of getting lots of support and helpful advice
that was never available in pre-internet days.

Bronwyn ;-)




Kennedy McEwen wrote:
In article , HC writes

G'day

Now that I've got my Canon scanner operational again, I've been having
some discussion regarding dpi and wondering what people here suggest?

The main group of photos in this project are 3.5 inch x 5.5 inch with
a few around 6 x 8 inch but all are around 50 year old B&W prints that
have been stored in albums so their condition is good.

I've always been under the impression that a higher dpi will give
better quality prints? I've scanned some photos at 1200dpi at 6 x 8
inches.....what does everyone suggest for best results?

B&W prints will generally have more information on them than the
standard rule of thumb of 300ppi for corner shop colour prints, but
generally this isn't more than 600ppi. With the poor MTF of that
scanner at 1200ppi and the limited information on the prints above
600ppi, I doubt that scanning at 1200ppi can be justified on any grounds.

Ideally you should scan at the limit of the equipment (in this case the
combination of the source material and the scanner probably sets that
around 600ppi) and archive this. Then resample to the optimum output
resolution for your final application using the best resampling
algorithm available to you.

Currently I'm saving these as .bmp because .jpg is too lossy and
thought I'd change this via IrfanView or Picasa. Suggestions on this
too please?


Save as Tiff with compression enabled: this is lossless compression
unlike jpeg - although the tiff specification permits jpeg compression,
few packages support it. Not only will you be able to save in less
space than .bmp format but, more importantly, you will be able to
archive your images with more bits per pixel, more dynamic range.

In the past I've just scanned a few photos, but this project is
archiving old and precious photos so I'd like the best reproduction
possible.

Best archive or best reproduction - they are not the same thing. Best
archive means saving more information that your existing equipment can
reproduce, because sometime in the future you will upgrade, and you
don't want to rescan everything all over again.

Thanks in advance for any suggestions
Bronwyn ;-)


Unusual name - only ever met one person called that before, they were
Australian too, but it sounds Welsh. ;-)

In article , HC writes

Kennedy...my name is Welsh, but I'm true-blue Aussie ;-)

But aren't all the true Aussie's black? ;-)
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

On Tue, 06 Sep 2005 14:23:08 +1000, HC wrote:


Catfish...good point! I know some of my early photos are colour prints,
so expect some others will come out of the woodwork now I've started
this archiving project, which seems certain to become bigger than I
envisaged.
One more thing, I don't know what app you're using to edit, but it's
sensible to scan the images as RGB. It makes it a lot easier to get
rid of any colour casts through, e.g., channels in Photoshop.

--

Hecate - The Real One

Fashion: Buying things you don't need, with money
you don't have, to impress people you don't like...

LOL.....got a point there!! Don't know my family history so can't
elaborate, sorry!! ;-))

Kennedy McEwen wrote:
In article , HC writes


Kennedy...my name is Welsh, but I'm true-blue Aussie ;-)

But aren't all the true Aussie's black? ;-)