Scanner for photos

[TCav]

With a conventional scanner, your photos will be scanned at, say for instance, 4,800 dpi. So a scan of a 3 x 5 photo will have a resolution of 14,400 x 24,000 pixels. But when you scan a slide or negative, it will have a resolution of only 4,535 x 6,800, because the original is only 1 x 1.33 inches.

Take the slides and negatives someplace that can do better.

[VTphotog]

Scanning prints at resolutions higher than 600 DPI is a complete waste of time, effort and storage space. Even 600 is overkill for most. Using 4800 dpi for slides and negatives gives you the equivalent of a >10 MP image, which will be more than adequate for 16x20" prints, if you intend to print them.
Since you have mentioned Photoshop, I guess you intend to do some editing - really large file sizes make that process take quite a lot longer. Take TCav's example of the 3x5 at 4800dpi and imagine the time it would take to load and edit.

brian

[iowa_jim]

The scanner is in the mail, a V500. No-one seems to have the V600 yet, and it isn't important to me, so I pulled the trigger.

I'm thinking about scanning at 1200dpi for processing and then reduce it to 600dpi for archiving. At least for the smaller photos. We'll see how the computer handles that, and if the output meets my needs.

200 dpi is adequate for printing digital photos, but it never seemed good enough for scans.

[TCav]

200 dpi is the resolution of a fax.

[iowa_jim]

I think there is a large difference in print quality when we compare resolution between a scanned image input to a digital camera output. My 18mp camera can take a 5184x3456 pixel resolution image. At 600dots per inch, and I imagine that each dot is a pixel in this case, my camera would barely be able to print a 5x7. In practice, I try to set my floor at 200 dpi for prints, and they look good to me. When it comes to scans, 200 dpi on the input side doesn't come close to creating an adequate image. Maybe it's my equipment or the way I use it, but these are my empirical findings.

I haven't gone into wholesale scanning yet, but with my tinkering over the years I'm expecting to scan at 600 or 1200 dpi depending on the size of the image (larger if the computer will handle it, historically it would not, but I've got a monster rig these days), but prints will probably be with my customary floor of 200 dpi.

Any insights into the chasm between input dpi and output dpi that I've noticed?

[TCav]

The printer driver upsamples images to obtain an appropriate output, based on the resolution of the image and the desired print size. If your photo printer has an output resolution of 1440 dpi, without any upsampling, images from your 18MP camera will print at 3.6 x 2.4 inches. If you were to print that 18MP image at 5 x 7, the printer driver would upsample the image to 72MP. An 8 x 10 would be 165MP.

Upsampling is accomplished through interpolation. That is, the printer driver makes up new pixels based on what it already knows about the pixels it has. Too much upsampling will average out detail.

You have the original photos. You can extract as much detail as you want. The more detail you extract, the better your reproductions will look. If you scan a 3 x 5 photo at 200 dpi, you'll have a 0.6MP image. If you want to print it out at 3 x 5, on that 1440 dpi photo printer, the printer driver will have to create 51 pixels for every single pixel you gave it.


Try it out. It will take 5 minutes.

• Scan a photo at whatever resolution you think you can get away with.
• Print it out at the same size as the original.
• Compare the copy to the original.

Note: Don't just hit the scanner's Copy button. The scanner will scan the original at the maximum resolution it's capable of, and the printer driver will actually have to downsample the image in order to print it.

[iowa_jim]

The scanner is due here this afternoon. I'll play aroud with it to see what happens.

[gsrunyan1]

Originally Posted by deadshot

I have had an Epson Perfection 4490 Photo I.C.E.for a while now and I had done loads with it with very good results, I paid £129 = $200 or so. It scans most negatives 35mm etc, even old box Brownie negatives which is why I mainly wanted it.I also have an Epson Stylus Photo RX520 for my printing which also scans and copies but does not do many negative sizes.Hence the 4490. I'm not sure about the economics of home printing any more, because the cost of ink is getting silly and the printing people have got a lot cheaper now.

Last spring, for my daughter's 10th wedding anniversary, I bought a Epson 4490 to scan the dozens of 110 negatives from her wedding. Although I was used to sanning 35mm negatives with a nikon film/slide scanner, the Epson did as good a job as I could have hoped for. I paid around $125 for the Epson. I think you will be very satisfied with the results.

Glenn

[TCav]

The Epson 4490 Scanner has a resolution of 4800dpi. A 110 film frame is 13mm x 17mm. Using an Epson 4490 to scan a 110 film negative will produce an 8MP image.

[iowa_jim]

I've been giving the V500 Epson a workout. I can create a scan at file sizes approaching 1 gb, but I can't edit them with my Photoshop plugin Topaz until I knock the photo size down to 125 mb or so. For snapshots I am scanning at about 4800 dpi, then I crop to recompose, then I resize to 8" wide at 800 dpi to achieve the necessary file size. This sets me up for a decent print size as well as for downsizing for a blu ray disk.

Even though Topaz chokes on anything over 125 mb, I can still scan to close to a 1 gb file while simulateously editing another file in Photoshop. Gotta love these new computers! I remember doing some things with a computer where literally moving the mouse during a computation would cause it to crash.