Scanning of 80y old B/W-Prints for achiving

[Anthony Nelson]

Hi,

I want to scan some old B/W-photos for achival purposes. I know the
rule of thumb that approx. twice the actual resolution of the print
should be chosen as the scanning resolution.

Do you have some hints about the resolution of such old prints? Some of
them are even 100y old 6x9cm (contact?) prints on cardboard and I don't
have any idea of the resolution of such photos.

Moreover, does 16 bit color width makes sense for such reflective
scans, as it does for scanning transparencies in order to have some
reserves for tonal corrections?

Anthony

 

[Norm Dresner]

| Hi,
|
| I want to scan some old B/W-photos for achival purposes. I know the
| rule of thumb that approx. twice the actual resolution of the print
| should be chosen as the scanning resolution.
|
| Do you have some hints about the resolution of such old prints? Some of
| them are even 100y old 6x9cm (contact?) prints on cardboard and I don't
| have any idea of the resolution of such photos.
|
| Moreover, does 16 bit color width makes sense for such reflective
| scans, as it does for scanning transparencies in order to have some
| reserves for tonal corrections?
|
| Anthony

I'm going to take a WAG based on what I remember about film resolution
(Gawd! is it that long ago?) 50 years ago when I was a teenager. I vaguely
remember that a decent lens on a slow film (and 80 years ago pretty much all
film was slow) could get around 50-75 lp/mm resolution. This would
translate (if my math is okay) to around 1200-2000 lp/inch. If you're
dealing with contact prints you probably have to figure on handling the
maximum resolution so scanning at about 1600-2400 PPI would certainly
capture everything that the finest lenses and film of the era could have
captured.

Personally, I think that, even for contact prints this is gross overkill and
would use something on the order of 800-1200 PPI.

Norm

 

[Per Larsen]

Hi,

I want to scan some old B/W-photos for achival purposes. I know the
rule of thumb that approx. twice the actual resolution of the print
should be chosen as the scanning resolution.

Do you have some hints about the resolution of such old prints? Some of
them are even 100y old 6x9cm (contact?) prints on cardboard and I don't
have any idea of the resolution of such photos.

Moreover, does 16 bit color width makes sense for such reflective
scans, as it does for scanning transparencies in order to have some
reserves for tonal corrections?

Anthony

I've just been scanning about 50 old prints (from about 1910-1930) and decided to go for 1200 dpi because I surely was able to spot a difference between 600 and 1200. I know you can't see the difference when reproducing the prints in (about) its original size, but I wanted to get as much out of them as possible with my CanoScan 5200F (which has a maximum of 1200 dpi on reflective scanning (but 2400 on film scans).

I've put up an example here: http://www.lyngsdalen.net/tmp/index.html

hth
PerL

 

[false_dmitrii]

I've just been scanning about 50 old prints (from about 1910-1930) and decided to go for 1200 dpi because I surely was able to spot a difference between 600 and 1200. I know you can't see the difference when reproducing the prints in (about) its original size, but I wanted to get as much out of them as possible with my CanoScan 5200F (which has a maximum of 1200 dpi on reflective scanning (but 2400 on film scans).

I've put up an example here: http://www.lyngsdalen.net/tmp/index.html

Uh oh, looks like you're making the same mistake I did when I started
scanning old prints. Your 600ppi images are way too pixelated; you
need to upsample them properly for comparison. At minimum, you need to
use whatever "Image/Resize/Resample using Bicubic" method is available
in your editor, but there's more you can do for the best results.
Search Google Groups for "false_dmitrii kennedy resample" for a thread
explaining the proper method.

Apart from the difference in smoothness, which is due to inadequate
resampling, the image on the right doesn't seem to hold detail worth
the added resolution. None of the lines are razor-sharp, and even the
blotches are multiple pixels across. My own scans of old B&W prints
offered similar results, with real gains between 300ppi and 600ppi but
almost nothing new at 1200 vs. a resampled 600. So read the thread I
mentioned and give the comparison another whirl.

false_dmitrii

 

[false_dmitrii]

Per Larsen wrote:


By the way, that's an interesting photo you used. Do you know the
story behind it?

false_dmitrii

 

[Per Larsen]

Uh oh, looks like you're making the same mistake I did when I started
scanning old prints. Your 600ppi images are way too pixelated; you
need to upsample them properly for comparison. At minimum, you need to
use whatever "Image/Resize/Resample using Bicubic" method is available
in your editor, but there's more you can do for the best results.
Search Google Groups for "false_dmitrii kennedy resample" for a thread
explaining the proper method.

Apart from the difference in smoothness, which is due to inadequate
resampling, the image on the right doesn't seem to hold detail worth
the added resolution. None of the lines are razor-sharp, and even the
blotches are multiple pixels across. My own scans of old B&W prints
offered similar results, with real gains between 300ppi and 600ppi but
almost nothing new at 1200 vs. a resampled 600. So read the thread I
mentioned and give the comparison another whirl.

false_dmitrii

OK, I've read your post (several times), and the thread you're referring
to (Search Google Groups for "false_dmitrii kennedy resample") from start
to end until very, very late yesterday night, but I'm still not sure about
what mistake I've done --- so, if you could elaborate on that one.

I've scanned the both the front and back side of each print using 300 dpi,
and finally the image part of the front side at 1200 dpi, the last one being
my 'digital negative' for archiving. For most of the images 600 dpi would
probably be sufficient, but, as I've said, on some of them (the examples
I've put on the web may not be the best ones) I can see finer details.

The four (pixelized) examples are (of course) from the eye region of the
gentleman on the complete original.


I still do not know too much about the story behind the photo, apart from
that it (well, they) have been my late grandmother's (my mother's mother).
This photo seems to have been taken at a photostudio (Chr. Hansen) in Tromsø
(northern Norway, Europe) in 1913.

PerL

 

[false_dmitrii]

OK, I've read your post (several times), and the thread you're referring
to (Search Google Groups for "false_dmitrii kennedy resample") from start
to end until very, very late yesterday night, but I'm still not sure about
what mistake I've done --- so, if you could elaborate on that one.

I've scanned the both the front and back side of each print using 300 dpi,
and finally the image part of the front side at 1200 dpi, the last one being
my 'digital negative' for archiving. For most of the images 600 dpi would
probably be sufficient, but, as I've said, on some of them (the examples
I've put on the web may not be the best ones) I can see finer details.

The four (pixelized) examples are (of course) from the eye region of the
gentleman on the complete original.

I might be misunderstanding you, in which case I apologize. From the
context of the thread, my impression was that your weblink was meant as
a straight comparison between the image detail you were getting at
600ppi and at 1200. If this was your intention, you first need to
Image|Resize the 600ppi to 1200 using Bicubic resampling. Otherwise
it's not a fair comparison.

I still do not know too much about the story behind the photo, apart from
that it (well, they) have been my late grandmother's (my mother's mother).
This photo seems to have been taken at a photostudio (Chr. Hansen) in Tromsø
(northern Norway, Europe) in 1913.

They have a striking old world appearance far removed from the American
turn-of-the-century look I subconsciously expect. I love getting fresh
glimpses into the past.

false_dmitrii

 

[Per Larsen]

I might be misunderstanding you, in which case I apologize. From the
context of the thread, my impression was that your weblink was meant as
a straight comparison between the image detail you were getting at
600ppi and at 1200. If this was your intention, you first need to
Image|Resize the 600ppi to 1200 using Bicubic resampling. Otherwise
it's not a fair comparison.


They have a striking old world appearance far removed from the American
turn-of-the-century look I subconsciously expect. I love getting fresh
glimpses into the past.

false_dmitrii

Oh, there's no need to apologise at all. It's always a good thing to learn
more about this topic (well, actually about any topic one finds interesting),
and in my last post I forgot to mention that the thread you lead me to was
very interesting and informative (even if it took some time).

I've also seen (from new scans) that my examples were not very good. I still
think I get more (wanted) information when scanning at 1200 dpi, but the newer
scans are not so much convincing. I may be putting up new examples on the web,
and in that case I'll put a note here.

PerL