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Spyneyes
16 September 2006, 03:24 AM
I'm going to ask family members from the far stretches of the U.S. to collect their pictures of our common family and ancestors and have them scanned. These photos could range from the old black & white polaroids to snapshots of varying sizes typical of the 20th century. They would also include civil war era photos as well as the larger 8x10 or even bigger portraits from as early as the late 1800s.

I know they should be scanned in one of the "lossless" formats such as TIFF or PSD. BUT what dpi should I ask them to have these scanned at? It's uncertain to what purposes these files may ultimately be used for, except for the fact that I will be posting some of them on a web site. HOWEVER there may also be those of my family (including myself) that would appreciate the ability to print them for display in our homes in sizes of as large as 8x10s maybe even 11x14s, or within a photo book or on other consumer products available. I guess basically anything reasonable is possible. The problem is ... it's difficult to predict these several variables including the quality of the original photo or the equipment that will be used, after it's scanned, for later reproduction. With permission from the photo owners I will provide the needed files for these purposes.

I'd like to make this as simple as possible for my relatives, some of whom are in their 80's and may not be computer savvy, while at the same time assuring that these family treasures will be preserved for multiple purposes for generations to come. In some cases this may be the one and ONLY opportunity to have these various images preserved digitally -- certainly during my lifetime.

So what's a reasonable dpi to ask for? 300 dpi, 600? OR greater? OR should I simply ask them to have them scanned at whatever highest quality setting is available from the scanner, understanding that most of these will be scanned by a business such as Fed Ex/Kinkos.

Thank you in advance for your thoughts and any other ideas you'd like to offer on this subject and it's process. This is an extremely helpful medium and I very much appreciate your time and consideration.

Best regards!

marnen
16 September 2006, 02:15 PM
For screen display, 72 dpi. For printing, I'd say that you want to shoot for 300 dpi if you're going to print at actual size. If you're planning to blow the pix up, you may want higher resolution so that quality is retained.

And you should be aware that some scanner software does not offer an easy way to scan an image in any format other than JPEG. If that's the case, just ask for the highest image quality, and convert the image into some other format when you get it.

Blaise A. Darveaux
22 September 2006, 12:28 PM
Doesn't the appropriate scanning DPI depend on the size of the object that you are scanning? For example, if your scanning a 35mm film you may want to scan it at 1200? 2400? 3600? But don't try scanning a 8x11 photo that high or the scanner/computer will choke on the resulting huge file. Certainly you want the most information that you can get without bringing your equipment to its knees. I think what I have done in the past is once I have done a preview scan, I then fiddle with the DPI until the resultant file is several megabytes in size (1 to 10?). When I first started scanning I was thinking "more is better" so I scanned a 7x5 photo at 800 DPI and ended up with a file over 100 MB in size which brought my PowerComputing Power CenterPro 210 (which I am still using, BTW) to a crawl. I am sure there are some guidelines or rules-of-thumb somewhere for this. Once you have the scan in an appropriatly sized file, save it in a loss-less format for archive and use it to save copies at other sizes and in other formats depending on how it will be displayed (computer monitor, printed on photo paper, thumbnail, billboard, giant stadium screen, WANTED poster, etc.)

Oh yeah, and don't throw away the originals once their scanned. They may have to be rescanned. Someday we'll have scanners that will convert 2-D photos to 3-D holograms which will then be linked to an AI processor so that you can talk with your ancestors blah, blah, blah.... Oops, sorry, I got off on a tangent.

Blaise A. Darveaux

Spyneyes
23 September 2006, 02:57 AM
For screen display, 72 dpi. For printing, I'd say that you want to shoot for 300 dpi ... some scanner software does not offer an easy way to scan an image in any format other than JPEG. If that's the case, just ask for the highest image quality, and convert the image into some other format when you get it.

Thanks for your reply, it's very much appreciated.

Spyneyes
23 September 2006, 03:13 AM
Doesn't the appropriate scanning DPI depend on the size of the object that you are scanning? For example ... Oh yeah, and don't throw away the originals once their scanned. They may have to be rescanned. Someday we'll have scanners that will convert 2-D photos to 3-D holograms which will then be linked to an AI processor so that you can talk with your ancestors blah, blah, blah.... Oops, sorry, I got off on a tangent.

Blaise A. Darveaux
That's okay I got a chuckle out of your thoughts re: the future. I appreciate your reply.

My main problem right now is that I'm most concerned about making it as easy as possible for my relatives, that may not be that computer savvy, to provide me with scans of mostly old family photos for inclusion in Reunion and eventually on the web. The majority won't have a scanner of their own and will be depending on commercial places to provide the service, so they won't have the capability to do much experimenting.

With the ability to store files on CDs and DVDs I'm not that concerned about the size of the original file, BUT want to know what's a *reasonable* range in resolution to be shooting for.

As to your question regarding the size of the original ... I don't know myself, but will be curious to read future replies, so I can pass the info on.

Thanks again for your help!

Karen Peters
23 September 2006, 09:40 AM
You can learn more than you ever need to know about scanning from http://scantips.com/ (This is geared to do-it-yourselfers)

This link will lead to an article on dpi for printing:
http://scantips.com/basics02.html

If your relatives will be taking the photos to a business, I suspect they have some standard dpi that they use when scanning. You might just call ahead and talk to someone and ask what they recommend.

Good Luck,

Karen

Edit:
I haven't used this business and it is not an endorsement. I know people are paranoid about sending their pictures out (I don't blame them). But this business http://www.digmypics.com will scan pictures or slides that are mailed into them. You might browse around their website and see what kind of services are available.

theKiwi
23 September 2006, 09:47 AM
Within reason, I scan things at the optical resolution of the scanner. The optical resolution is the number of dots the scanner can see, without using any software interpolation to create extra dots that it thinks should be between the ones it does see.

Within reason is because clearly as already stated, you wouldn't want a 2400 dpi scan of a photo that's 11 x 14 inches, but a 2820 dpi (the resolution of our Minolta film scanner) scan of a 35 mm slide is certainly warranted.

But back when the optical resolution of my flatbed scanner was 400 dpi (and that scanner had cost $1100 - my how things have changed!!!!!), that was a reasonable amount to scan anything that would fit on the letter sized bed, especially if your having it to scan was a one off thing - that you had the photo on loan, or were at someone's house scanning what they had.

More is better usually, especially if the original is fairly good quality. I have many olde family pictures that were essentially contact prints from film formats like 620, so they are quite small - 2 x 3 inches. If you wanted to print that out at 8 by 10 using 200 dpi, you'd need to scan it at at least 800 dpi.

For what you're thinking of doing, and your statement about file size etc not being too big of a concern, I'd suggest something like 800 - 1200 dpi for photos up to 6 x 8 and 600 - 800 dpi for photos larger than that. Save all the originals that are sent to you, and downsample them for use in Reunion and on the web. For images on my web site I usually aim for about 800 pixels wide (at 72 dpi - not that the dpi matters as all browsers show images with 1 image pixel taking up 1 screen pixel if no deliberate attempt by the site's author changes that). For more detailed things like census returns I make them 1000, or even 1200 pixels wide so they can be read online with minimal scrolling needed on "most" screens.

Note: a Google analytics running on my site for the last couple of months indicates that the most common screen size of visitors is 1024 x 768 - nearly half the visitors have this, while about 11% of the visitors can't see something 800 pixels wide on one screen.

Roger

Rank. Resolution - # of Visitors - percent of total
1. 1024x768 - 801 - 48.02%
2. - 1280x1024 - 249 - 14.93%
3. - 800x600 - 182 - 10.91%
4. - 1280x800 - 74 - 4.44%
5. - 1440x900 - 70 - 4.20%
6. - 1680x1050 - 59 - 3.54%
7. - 1152x864 - 57 - 3.42%
8. - 1920x1200 - 32 - 1.92%
9. - 1280x854 - 27 - 1.62%
10. - 1344x840 - 17 - 1.02%
11. - 1280x768 - 16 - 0.96%
12. - 1280x960 - 13 - 0.78%
13. - 640x480 - 11 - 0.66%
14. - 1600x1200 - 10 - 0.60%
15. - 1400x1050 - 9 - 0.54%
16. - 1600x1024 - 6 - 0.36%
17. - 1024x640 - 5 - 0.30%
18. - 1152x870 - 5 - 0.30%
19. - 1440x960 - 4 - 0.24%
20. - 832x624 - 4 - 0.24%
21. - 1056x792 - 2 - 0.12%
22. - 1024x763 - 2 - 0.12%
23. - 1152x768 - 2 - 0.12%
24. - 2560x1600 - 2 - 0.12%
25. - 1024x820 - 2 - 0.12%
26. - 1536x960 - 2 - 0.12%
27. - 1152x720 - 2 - 0.12%
28. - 1280x720 - 1 - 0.06%
29. - 1600x1000 - 1 - 0.06%
30. - 1120x840 - 1 - 0.06%

Spyneyes
24 September 2006, 03:20 AM
You can learn more than you ever need to know about scanning from http://scantips.com/ (This is geared to do-it-yourselfers)

This link will lead to an article on dpi for printing:
http://scantips.com/basics02.html

Karen,

Thanks so much for your help on this subject. It's appreciated. And to think a simple Google search *on my own* may have come up with these tips. Why didn't I think of that!

Best regards!

Spyneyes
24 September 2006, 03:28 AM
Roger,

Thanks again for your input. Very, very helpful. I will make a hard copy of your information and refer to it regularly in my scanning needs.

I've been using personal computers since the early 80s and can remember being more than happy to pay $1000 to max out my IBM-PC with 640k of RAM and another $700 for a 40 mb hard drive (Thats mega, not giga). :-)

As you wrote, "my how things have changed!!!!!"

Spyneyes
24 September 2006, 05:01 AM
You can learn more than you ever need to know about scanning from http://scantips.com/ (This is geared to do-it-yourselfers)
Karen,

Now that I've had some time to look at the web site you recommended I found exactly what I was looking for!

There are a lot of indepth articles and explanation on the site, but I found all the basics that anyone should need including the math involved in his FAQ section under the question, "What Scanning Resolution Should I Use" 300 dpi?

This web site is excellent and should tell most folks anything they'd need to know in buying and using scanners. It also has a "How To" on "The Restoration of Genealogical Photographs" that explains the procedure to restore a badly faded and creased 1917 photo into looking brand new. It includes before and after photos and screen shots to pave the way. Very impressive!

http://scantips.com/restore.html

I highly recommend anyone interested in this subject to take a look at this site.

Thanks again for your help!