We just got a new scanner last night, and I’ve been scanning like a madman. I’ve run into the problem of how to save the files. Not the actual HOW to do it, but things like what file format to use. Some specifics. . .
Space is not particularly an issue as I have a CD burner and a LOT of spare blank CDs floating around. I’d say most of the pictures are standard 4 by 6 prints. I’ve been getting somewhere close to 6 MB at the largest (per picture) depending on how much I crop. This is a 300 dpi .bmp file.
What will they be used for? Well, aside from the odd printing one off to give to someone, the only thing I can think of is if someone wanted to put some on the internet for one thing or the other. I would say the main reason is storage.
My question(s):
What file format should I be saving these pictures in? I would like to keep as much quality as I can within reason.
What resolution should I be scanning them in in the first place?
If any more information is needed, do not hesitate to post or email. Thanks in advance.
For any practical use JPG is what you need. BMP is needlessly big. Now, in JPG you can set more or less compression and the only judge of the result are your own eyes. Just experiment a bit and you’ll soon get the hang of it. Save several pictures with different degrees of compression. If you are not sure, just choose low compression which will yield a bigger file size, but still much smaller than BMP.
If you are posting any pictures online, try to keep the file size reasonably small. I have little patience for downloading huge files. My rule of thumb is to make the file as small as possible and still show what i want. If the file has to be large (anything greater than 100K) then post a thumbnail with a link and mention the file size.
Ocassionally I come accross a web page where someone has posted a dozen pictures of 25KB each. Needless to say, I am not going to wait around for that unless I have an extremely good reason.
I take a lot of wilderness and wildlife shots on my backcountry travels. From my personal experience, I can offer the following tips:
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Scan prints at the highest reasonable resolution to create a “Master Scan”. Once scanned, you should not have to go back to the print. Unless you’re a professional, 400 dpi is the ideal resolution for most purposes. If you take a lot of detailed shots or closeups, 600 dpi is preferable. Anything higher either takes too long to scan, or results in gigantic file sizes and unnecessary detail.
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Any duplicate or subset that you may need to email or print can be created with an image editor based on the master scan. Never alter the master scan once saved.
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Unless you have a good scanner, you’ll need to do some color correction. Soem scanning utilities allow you to save a color mask to apply to all scanned images. Chances are, the scanned image will be too dark. It only takes a few minutes to familiarize yourself with the various controls.
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File format. For normal purposes, there’s no reason to keep these images in bitmap format. They take up far more space. I use JPG with a max of 5% compression. Sure, there is some loss, but it’s barely noticeable. The file sizes are significantly reduced. Don’t bother with native formats like PDD. They save things like layers and masks which are unnecessary, bloat the file size, and may not be compatible on other machines.
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Make sure that the scanner bed is clean at all times, and wipe down the prints before each scan.
Professional photographers may have different advice for you, but I think 400 DPI JPG scans are ideal for the home user offering maximum portability and image depth at the minimum file size.
Incidentally, at the time you have your film processed, you can often ask for a PhotoCD at an additional cost.
A great site which has numerous articles on photography as well as scanning can be found at http://www.photo.net
I hit submit before adding this other site: http://www.scantips.com/ which offers a lot of newbie advice. The bottom line is that the quality of a scanned print will never be as good as a direct scan of film, but there’s a lot of great advice on making the most of a low-end home system.
The file format to choose really depends on what you want from your pictures.
Bitmaps (.BMP)
In general bitmaps stink as they tend to be very large in size. Also, while they are well supported in the Windows world they are poorly supported in just about everything else (which of course adds up to a drop in the bucket compared to Windows but still…).
JPEG (.JPG)
For most applications JPEG is the way to go. JPEG files can be 50 times smaller than a bitmap.
The downside to JPEG’s is they are lossy. That is, in order to be small they toss some detail out of the picture. Usually this isn’t noticeable but if you continually open then re-save (not just close the picture) then over time you may see image quality suffer. You can sometimes select how hard you want the program to compress a JPEG file…more compression = smaller file size = greater loss of detail. I believe it always supports 16.8 million color depths.
GIF (.GIF)
The GIF file format is generally only good for cartoons or simple drawings (such as line art). The GIF specification can only handle 256 colors but it has pretty good compression.
TIFF (.TIF)
This is a widely used and supported image format although I’ve had little experience with it. Overall this seems the best choice for sharing files between differing systems as it is widely supported (TIFF LZW is not so widely supported due to licensing issues). It also retains the best quality of image but I am unsure how it equates on file size.
In short:
Best Quality = TIFF
Smallest File Size = JPEG
FWIW there are many file formats I haven’t included (PCX, PICT, PNG, etc.). I’ve just included what I think are the most common. Feel free to ask about other formats if you wish.
To add to what others have said - if you propose to display the pictures on a web page, be sure to change the resolution from 400 dpi to 72 dpi for the copy that you will be displaying on your web page.
When space is not an issue, as it is apparently not, you should NOT save in lossy compressed formats like jpg. Once a file is saved in jpg format, you can not edit it and resave it without substantial loss in image quality. Surely you’ve seen jpgs that were resaved and show massive image artifacts.
Save the file in a standard compressed format, like PICT or TIFF. These have non-lossy compression and are optimally compressed without degrading image quality.
I always go with…1200 DPI, and then I just change the picture size AFTER I scan it. So, I should probably scan as a TIFF, edit it, and THEN change to a JPG?
If your main concern is storage and space is not an issue, scan at your highest resolution and use a non-lossy format such as TIFF. Don’t use JPEG because you never know, you might want to manipulate/edit your images some day.
Do all of your editing BEFORE saving to JPEG. If you save your image during editing (which is always a good practice) use a non-lossy format such as TIFF or BMP, or your image editor’s native format. As Chas.E and Whack-a-Mole have said, re-saving a JPEG is never a good idea.
In figuring out what image size to use, you must consider the output:
Screen resolution is 72 DPI. As such, for an image to appear 4in x 6in on screen, it would be 288 x 432 pixels. The viewing area of most computer monitors is 1024 x 768 or somesuch. If you scan a 4x6 print at 600 DPI you get an image 2400 x 3600 pixels.
If you want to print your images, my best advice is dig out the negatives and get prints made from them at Wal-Mart. They’re pretty cheap and infinitely better than any home digital printer.
If you want to do some fancy digital editing and print the result at home, scan and work at the highest resolution you can. Find out the output resolution of your printer (most inkjets are - what? - 600 DPI?) and multiply that by the output image size you want (in inches) to get the image size (in pixels) you need to work on. A print resolution of 600 DPI and an image area of 8 x 10 inches means a working image size of 4800 x 6000 pixels and one enormous file size.
You can certainly print at a lower resolution or make a smaller print, but that quickly reduces the usefulness of printing your work in the first place. You want your images to make an impact, right?