Advice Please: Scanning Stamps For Internet Posting/Auctions

What's the best way to scan stamps for auction. Space isn't an issue (I have more server space than I'd ever need), but speed/efficiency is. I want to scan, crop, save, and move on.

What scanning dpi should I use? 100? 150 (surely enough)? or 75 because that's all that' really needed?
(I'm scanning thousands of stmaps so the faster I can do it, the sooner I'll be done)

Should I scan at more than 1x? Say 2x or 4x -- bigger is more visible and shows more detail (but it's also a bigger file, longer to dl for some)?

Should I create hi-res/large size scans and then batch convert them to a smaller size/res?
I could scan everything at 4x size, 150 dpi, JPG 75% compression and then batch convert to 2x, 75 dpi, JPG 50% compression, changing the filename to indicate it, and have both items on the server. But is there any point in doing it?

What settings do you use for your scanning for auction listings?

Tom, there's a BIG difference between 200% at 75 dpi and 200 dpi at
75% !

In the first you're scanning with a low sampling rate, then magnifying the result. In the second, 'srcanning at photo rate (print paper has
200 dpi res - approx.) and then reducing.

IMHO, you should scan at the dpi ( with "100%" setting) that gives you the end size. ANY additional manipulation, especially AFTER saving as a jpg, can only reduce the quality.

For me, singles at 150 dpi, larger items at smaller dpi. Remember most people want to 'use a magnifier to examine stamps, so 1.5x is quite appropriate. For errors or plating 2x is great!

NO, 72/75 dpi is no longer the display standard on most computers.
With larger screens and higher scanning (1024x768 is 'norm' the effective ppi is about 96 to 108. So AFAIAC 100 dpi is 'life size'.

found these unused words floating about:

You might find my "Tips on Scanning" web page helpful: http://www.pgacon.com/tips_on_scanning.htm

Scanning is black magic. I have spent about a zillion hours (I'm a slow learner) to determine I get the best images for internet use if I scan at
72dpi, but make the initial scan as big as my computer can handle with reasonable speed, and not choke.

Using this method, the first raw image of a typical postcard takes up about
3 megabytes. My next step is to scale it down to the size I need it to display at; a postcard ends up at approximately 50k, and would be considerably smaller if I had better compression software. I use the scanner setting for "glossy photo" and I get excellent detail (with no moire patterns with halftone images; even the paper fibres at the ends of perf teeth show clearly).

It is nice to have the large image, from which you can make good prints if you need to, or crop to show specific parts of the image such as postmarks.

Roy Lingen uses and swears by Irfanview for manipulating images. Apparently you can do batch processing of X number of scans, sharpening them and raising the contrast all at once. Since he uploads as many as two or three thousand good cover images to his websites every month, it obviously works pretty well. I believe that Irfanview is shareware. There is a similar program for the iMac, but I don't recall the name.

One thing I've learned is that it's much better to scan even black-and-white items in color, which gives much more detail; "black-and-white" often contains subtle but important shades of various colors.

I may be all wet about my scanning ideas. Perhaps there are quicker ways to achieve the same end, but if so, I haven't found them. For some reason that
I certainly can't explain, hi-res images (300dpi for example) don't look as good in the end as low-res images. Anyone have an explanation, without using words that didn't exist in 1975?

One thing that really baffles me is my digital camera, a Canon G4. It produces beaufiful prints, up to 16X20 inches if I want to do that. The on-screen images and one-hour prints are incredibly detailed, better by far than one-hour prints from negatives. To me, this means the images are
"hi-res". But the camera produces raw images that are only 72dpi. I DON'T
GET IT!

I don't know how old your camera is but mine is an Olympus 4.0, not very old. At the middle resolution setting the picture is 6 times larger than my 18" monitor.
At the highest setting it is as large as a barn. A sharp 16 x 20 image reduced to a 4" x 6" would be sharp. They all say 72 dpi but I have an in-camera function that will increase the dpi when I crop a picture so that cropping doesn't reduce the resolution.
Maybe scanning at a higher dpi doesn't mean more detail just more dots so then could 200% at 75 dpi be sharper than 75% at 200 dpi? These settings get the same size image on my monitor.
I have a Mac compression application "Fireworks".
If I scanned a cover at the highest setting I have it would be 9600 dpi at 1000%.
I think it might be too much.

I would say that it depends upon the stamp. I have been looking at auctions for early Norwegian posthorns, where very small differences in design separate different issues. I am constantly frustrated by scans that are so small that I cannot even tell if the stamp is a pre-1893 sans-serif issue or the later Roman letter issues. Let alone some of the smaller, but important, differences.

It seems to me that most of your time will be spent setting up the scan, rather than by the scanner itself, so I would not personally worry much about that.

If you scan at a higher DPI, you can create a smaller DPI image to use directly on in your auction description and then provide a link to a more detailed scan. That would provide a fast DL for the auction page, while providing a more detailed scan to those who want it.

BTW, why do you call 75 DPI scans "2x"? 72 dpi used to be considered
"1x" for web use, but with the higher pixel density on newer displays, it is really less than full size for most people.

The term DPI is pretty meaningless when it comes to digital cameras.
The only important things are the number of pixels and the number of bits per pixel.

<snip>

I don't. there's a "," stuck right in there.

150 dpi at 50% to get life-size, then to go larger I go to
300 dpi at 50%, if that is not large enough I go to
300 dpi at 100% which gives me an image 10 times life (minimum for a stamp). At that size the scanner is still fast.
300 dpi at 150% I get 20 times life, scanner gets slow.
Reversing the numbers gets the same results
75 dpi at 300%, almost large enough
100 dpi at 300%, 10 times life (the minimum for a stamp)
150 dpi at 300%, 20 times life
Scan things to the size you want on the auction, saves time.
Compression is a waste of time and potentially turns a good scan into a crap scan.
I like to buy from buyers who have large clear scans and tend to lose interest on the auctions that have small ones. The different picture services have gotten better with the supersize option. I look at other sellers jpegs.
fairstamp has great scans, simple formats, no excess verbiage and html.
I scan a page of stamps in Photoshop , outline a stamp, drag, drop into a pre sized blank, crop, and save.
Or faster:
Duplicate the page, crop, and save