Pixels and Inches

[cabinetman]

Here's the problem. I have to email some insurance forms to my agent. I scan in the document (8 1/2" x 11"), and the pixels are 1257 x 1565. Another document scanned in shows 15" x 21", and the pixels are 1140 x 1523. What's the deal?
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[RayintheUK]

Scanning resolution? You should be able to set it on the scanner software. Doesn't need to be very high for document scanning, somewhere around 300. Perhaps the resolution differed on your pages?

Ray

[leehljp]

Scanning resolution? You should be able to set it on the scanner software. Doesn't need to be very high for document scanning, somewhere around 300. Perhaps the resolution differed on your pages?

Ray

I agree with Ray. My thoughts too. Did you do auto scans or do you do set up the scans manually? I have auto but I never use that. I determine each scan's area, the DPI and color/gray/BW and more.

[Alex Franke]

I agree, too. Looks like the first one was scanned at ~150 dpi, and the second at ~75.

[cwsmith]

I generally don't pay much attention to the total scan width, I just go by the dots per inch.

My career has been in technical publications and I've been using a scanner for more years than I can remember. I've found that 200 dpi is excellent for scanning documents for sending or archival purposes and I scan all my paper records at that resolution. You should make sure that the setting is appropriate with regard to black and white or color. A color scan at 200 or 300 dpi is going to be extremely larger in file size than a black and white scan.

Through experimentation, I've found that 300 dpi will capture every "flyspec" on an 8 x 10 photo or letter-size sheet. I use that for capturing old photos. Fortunately old photos are usually black and white (actually that's continuous tone "grayscale" which is multiple tones of gray from almost white to almost black. It's a larger file size than 2-bit black and white, but it's still smaller than color at the same dpi resolution.

(Regarding resolution, it can get confusing as printed resolution and scanned resolution differs somewhat; it's in the actual "dot" detailing. I recall reading, many years ago, that National Geographic is printed at 300 dpi. Not sure if that's totally true, but 300 dpi is a remarkable resolution.)

Of course if your going to scan a small image like a stamp, you'll want to increase the resolution (dpi) to about 300 dpi for whatever size you want your final image. In other words, if your original is only an inch wide and you want to enlarge it to four inches, your dpi setting should be 1200 dpi.

As far as scanners are concerned one would think, like most things, the more expensive the better... but, I've found that not to be necesarily true. I have an old Visioneer 440 which cost me about $40 after rebate. It remarably did a better job on color rendention and black and white detail than my office $1000 plus HP. Go figure!

I hope this helps,

CWS

[Ed62]

Yeah, it sounds like a scanning resolution difference. As for the difference in file size, if you scan something at 300ppi, and rescan it at 150ppi, you'll find that the 150ppi will have a file size 1/4 the size of the 300ppi. Insurance forms should not require high resolution scanning.

Through experimentation, I've found that 300 dpi will capture every "flyspec" on an 8 x 10 photo or letter-size sheet. I use that for capturing old photos. Fortunately old photos are usually black and white, so the file size is rather small.

I always scan my B&W photos in color mode. If you do any restoration, you'll find that many times you can get much superior results doing corrections in color, by manipulating the RGB/CMYK amounts used (channels). It's sometimes even possible to bring out detail that cannot be seen in the original. After corrections are made, the file can be saved in grayscale.

Ed

[cwsmith]

Ed (and others),

Yeah, (bad day here) I meant to say "gray scale" (continuous tone) for photos. "Black and White" is strickly for line art!

For sepia toned photos I've used a color mode (my Visioneer 4400 is only capable of 42-bit depth scale), but haven't found too much advantage given the file size.

I use PaperPort software for document scanning and it makes the task quick, simple, and more than adequate for our purposes. In addition to personal tasks like IRS, medical, and insurance records, I use the scanner to archive the records for our exam team. The whole process is quite reliable, even capturing 3rd sheet carbonless copy printed on pink. The scanner will capture detail that my eyes can't.

I highly recommend a scanner for any business or household.

CWS

[cabinetman]

Thanks for the help so far. I haven't selected any specific resolution or set any sizes. What I am experiencing is maybe just a lack of information as to settings. I have two basic problems.

The first is to email insurance forms. I can scan one page and select in the menu to go to email with the scan. This puts an attachment on an email format, where all I do is add an address, and a subject if need be. But, I can only do one page per email. If I have two pages, I have to make two separate emails. Now if there is a way to scan to email, and keep adding attachments to the same email I would be happy. Doing it this way allows the recipient to open up the attachments and print them 8 1/2" x 11".

The second method I use is to scan the document to "clipboard", then paste it in Adobe PS, and "save as" a JPEG to "my pictures" and add a tag. Then when I email, I just browse "my pictures", and can keep adding attachments. This is where the sizing got screwed up with pixels and inches. If I save the JPEG and when sizing use 8.5 inches (for width), and 11 inches (for length), instead of selecting pixels, will the attachment get sent and be able to be opened up and printed by the recipient 8 1/2" x 11"?

I'm familiar with resizing as I do that for forum stuff.
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