What are the best scan settings for archival photos?
March 16, 2010 5:16 PM
Help me scan some precious old family photos! I need advice on the best settings to use: TIFF, dpi, encodings, and the rest of it..
I have quite a few old family photos, some from the early part of the century, that I'd like to digitize. There are two goals: (1) Preserve as much detail as possible. (2) Save them so that they can be printed, either for a photo gallery or in a book.
So, I'm using 1200 dpi and 48-bit color. I've figured out that TIFF is better than JPG for archival purposes. But here it gets tricky. My scanner has two options for TIFF: "Macintosh or Windows Byte Order". No idea what this means. I use both operating systems (usually Mac), but I want to save these images in a way that will open on either one. There are two more options to consider: B&W Compression: None or CCITT Group4, and whether or not to embed an ICC profile. Any experienced scanners out there that can help me out with these questions?
I have quite a few old family photos, some from the early part of the century, that I'd like to digitize. There are two goals: (1) Preserve as much detail as possible. (2) Save them so that they can be printed, either for a photo gallery or in a book.
So, I'm using 1200 dpi and 48-bit color. I've figured out that TIFF is better than JPG for archival purposes. But here it gets tricky. My scanner has two options for TIFF: "Macintosh or Windows Byte Order". No idea what this means. I use both operating systems (usually Mac), but I want to save these images in a way that will open on either one. There are two more options to consider: B&W Compression: None or CCITT Group4, and whether or not to embed an ICC profile. Any experienced scanners out there that can help me out with these questions?
I disagree with archivist on several fronts. For my day job, I write image processing software and have the most of the TIFF spec committed to memory.
Specifying a byte order is not optional in TIFF. It is REQUIRED by the spec and all readers are expected to handle the either of the two byte orders. The most common, in my experience is Intel byte order.
Non-lossy compression is not inherently bad. All of the compressions in baseline TIFF are completely specified and must be supported by conforming readers. The only one I would steer away from in day-to-day usage is called "old-style JPEG", which is an aberration foisted upon the world by Redmond.
CCITT Group 4 is specifically for 1 bit images and can't be used with other formats. It is a completely acceptable non-lossy compression.
I would probably use LZW or Flate compression for color if your scanner software has them as options. Both are non-lossy and will reduce file size by around 20%.
JPEG can be set into a non-lossy compression by some programs (scanner software probably doesn't give you access, though), and I would consider this acceptable for archival purposes. You can also embed JPEG compressed images in TIFF files, but most software won't give you enough control to set the compression level to non-lossy.
I would put the ICC profile in. In most cases, it won't hurt. In the best cases, it will make sure that prints made from them in the future are faithful.
As far as resolution is concerned, I would scan at the highest resolution natively supported by the device. Some of the high end resolutions are interpolation and not real resolution.
posted by plinth at 6:11 PM on March 16, 2010
Specifying a byte order is not optional in TIFF. It is REQUIRED by the spec and all readers are expected to handle the either of the two byte orders. The most common, in my experience is Intel byte order.
Non-lossy compression is not inherently bad. All of the compressions in baseline TIFF are completely specified and must be supported by conforming readers. The only one I would steer away from in day-to-day usage is called "old-style JPEG", which is an aberration foisted upon the world by Redmond.
CCITT Group 4 is specifically for 1 bit images and can't be used with other formats. It is a completely acceptable non-lossy compression.
I would probably use LZW or Flate compression for color if your scanner software has them as options. Both are non-lossy and will reduce file size by around 20%.
JPEG can be set into a non-lossy compression by some programs (scanner software probably doesn't give you access, though), and I would consider this acceptable for archival purposes. You can also embed JPEG compressed images in TIFF files, but most software won't give you enough control to set the compression level to non-lossy.
I would put the ICC profile in. In most cases, it won't hurt. In the best cases, it will make sure that prints made from them in the future are faithful.
As far as resolution is concerned, I would scan at the highest resolution natively supported by the device. Some of the high end resolutions are interpolation and not real resolution.
posted by plinth at 6:11 PM on March 16, 2010
Thanks for both comments!
Just to recap what plinth said, to be sure I understand it:
(1) I do have to specify byte order, and if the choice is "Windows" or "Mac" I'd just as well choose Windows because it is the most common. But a program that reads TIFF should be able to read both formats.
(2) CCITT Group 4 is OK as an option ... ?
(3) I should check the option for ICC profile; it can't hurt and may help.
[I do not seem to have the option of LZW or Flate compression. I'll look into the possibility of running the scan from Photoshop.]
posted by bchaplin at 6:23 PM on March 16, 2010
Just to recap what plinth said, to be sure I understand it:
(1) I do have to specify byte order, and if the choice is "Windows" or "Mac" I'd just as well choose Windows because it is the most common. But a program that reads TIFF should be able to read both formats.
(2) CCITT Group 4 is OK as an option ... ?
(3) I should check the option for ICC profile; it can't hurt and may help.
[I do not seem to have the option of LZW or Flate compression. I'll look into the possibility of running the scan from Photoshop.]
posted by bchaplin at 6:23 PM on March 16, 2010
(1) yes and yes
(2) only for 1-bit black and white images
(3) yes
wrt - to PhotoShop - yes, scan it into PhotoShop, thereby bypassing the scanner software's TIFF generation. PhotoShop will give you somewhat better options for compression, including flate and lzw, if I recall correctly. PhotoShop's support for color profiles is better than most programs.
posted by plinth at 6:34 PM on March 16, 2010
(2) only for 1-bit black and white images
(3) yes
wrt - to PhotoShop - yes, scan it into PhotoShop, thereby bypassing the scanner software's TIFF generation. PhotoShop will give you somewhat better options for compression, including flate and lzw, if I recall correctly. PhotoShop's support for color profiles is better than most programs.
posted by plinth at 6:34 PM on March 16, 2010
(2) CCITT Group 4 is OK as an option ... ?
Not an option. You're scanning in 48bit, and CCITT Group 4 is for 1-bit images. [It's commonly used in FAX applications; CCITT is the "International Telegraph and Telephone Consultative Committee"]
If your software is set to something other than 1-bit or B&W, I wouldn't expect that you'd be able to select CCITT Group 4, but if you can I'd leave it at "None" just to be safe.
posted by chazlarson at 6:45 PM on March 16, 2010
Not an option. You're scanning in 48bit, and CCITT Group 4 is for 1-bit images. [It's commonly used in FAX applications; CCITT is the "International Telegraph and Telephone Consultative Committee"]
If your software is set to something other than 1-bit or B&W, I wouldn't expect that you'd be able to select CCITT Group 4, but if you can I'd leave it at "None" just to be safe.
posted by chazlarson at 6:45 PM on March 16, 2010
This thread is closed to new comments.
posted by archivist at 5:46 PM on March 16, 2010