Is there any advantage to retaining bitmap files when scanning old RR photos for preservation purposes? My scanner defaults to the bitmap format, but after retouching, size adjustment, etc. I save all photos as JPEGS for working copies and posting purposes. I keep the original scan unchanged as a bitmap. However, BMP files are space hogs compared to JPEGs. Am I needlessly cluttering up my hard drive with unneccessary "originals", or are JPEGs good enough? I'm kinda paranoid from recording days when the original tape, however good or bad, was the best you were going to get. Thanks for any help you can give me!

drs5260fr@yahoo.com

> Is there any advantage to retaining bitmap
> files when scanning old RR photos for
> preservation purposes? My scanner defaults
> to the bitmap format, but after retouching,
> size adjustment, etc. I save all photos as
> JPEGS for working copies and posting
> purposes. I keep the original scan unchanged
> as a bitmap. However, BMP files are space
> hogs compared to JPEGs. Am I needlessly
> cluttering up my hard drive with
> unneccessary "originals", or are
> JPEGs good enough? I'm kinda paranoid from
> recording days when the original tape,
> however good or bad, was the best you were
> going to get. Thanks for any help you can
> give me!

Well JPEGs are stored using what is commonly described as a "lossy cosine-squared compression algorithm". What this means is that every time you save a JPEG, some of the original information that comprised the photo is lost in the compression process. Many edits, much loss.

That having been said, I usually don't save bitmaps either.

http://www.steamlocomotive.info
dougb@sunserver.com

If the photos are critically important to you and future generations (museum archives or the like), then take the trouble to make TIFF-format files and burn them to CDs. If you think BMPs are space hogs, you will be shocked at the massive size of TIFFs (the ones I work with average one megabyte apiece, or one per floppy if I'm lucky!), but they are the best way to keep the images from degrading over time--sort of comparable to wearing out videotape versus not wearing out a DVD.

This is NOT a suggestion for the "roster shot of the day" kind of snapshots, but rather the instance when someone loans you an album full of late 1890s action shots of steam locomotives or streetcars, and who knows where the album will end up in future years..........

lner4472@bcpl.net

Although TIFFs (Tagged Image File Format) is much larger than JPEG, they are pretty universally considerably smaller than BMPs. BMPs are raw data with no compression. As such they are simple to decode and use no proprietary compression algorithms. That is likely why Microsoft used it as the default file format for MS Paint. TIFF does have compression like JPEG and GIF, but it is not lossy and all data is retained. TIFF format is the format used for professional document archiving. I scan everything to TIFF format and derive the publishable JPEG from it. This is especially important since I use a higher order of compression on my JPEGs. The higher the order, the more data you loose but the smaller the file. It can be very handy for the website with limited space and you must strike a balance between quality and quantity. Just be careful in that TIFF supports different compression algorithms (including uncompressed, which may be what Sandy is reffering to) and one program that supports TIFF in one algorithm may not support it in another. GIF, although lossless, is not suitable for archiving because it only supports 256 colors, not enough for photo quality.

I use TIFF format to submit to our publication and the results are great. The size is high, three or four megs in greyscale and ten or more in color, but it is much less than it would be in BMP. The moral is use TIFF for 'keepers' and JPEG for 'quickies'.



The East Broad Top Railroad Homepage

ebtrr@spikesys.com

Your monitor has a 72 dpi resolution. So, as long as a file is saved at that or higher resolution, you won't be able to see any difference.
If you're saving photos for yourself, jpg is fine. It's also good for e-mail and web posting.
Get to printing/publishing, and you'll rue the day you made jpgs. The reproduce like horse.....
(fill in your own blanks).
Good reproduction needs between 200 and 300 dpi.
For publishing, BMP, TIF, or EPS are the formats of choice for art directors and printers.
After 20 years as a full-time editor, I learned the hard way. I hope you don't have to.

hankmorris@earthlink.net

> Is there any advantage to retaining bitmap
> files when scanning old RR photos for
> preservation purposes? My scanner defaults
> to the bitmap format, but after retouching,
> size adjustment, etc. I save all photos as
> JPEGS for working copies and posting
> purposes. I keep the original scan unchanged
> as a bitmap. However, BMP files are space
> hogs compared to JPEGs. Am I needlessly
> cluttering up my hard drive with
> unneccessary "originals", or are
> JPEGs good enough? I'm kinda paranoid from
> recording days when the original tape,
> however good or bad, was the best you were
> going to get. Thanks for any help you can
> give me!

I recently installed a rom burner. The cost of cds are 5 cents each and have a capacity of >700Mb. So now I scan images in bitmap format and save them on cds. Then as others have told you here, .jif is more than good enough for most usage, and .jpg are best for email and many other uses.

I scan at the maximum possible on my hp ScanJet in order to "get it all" into digital. I produce my own decals in all scales and find I need all the resolution I can get to regenerate text and images for decals. I have some files that are up to 100Mb. Now with my rom burner, I can offload these images, and load them only when working with them. This will free up a lot of hard disc space.

So, I reccommend scanning at maximum with a bitmap image, down size memory requirements with a .jif file and use .jpg for email etc. But get yourself a rom burner, they are getting very reasonable now, and save the raw high resolution bitmap image on a disc. After rebate I paid $120 for a high quality Yamaha rom burner.

dan


svry@pacifier.com

> Your monitor has a 72 dpi resolution. So, as
> long as a file is saved at that or higher
> resolution, you won't be able to see any
> difference.
> If you're saving photos for yourself, jpg is
> fine. It's also good for e-mail and web
> posting.
> Get to printing/publishing, and you'll rue
> the day you made jpgs. The reproduce like
> horse.....
> (fill in your own blanks).
> Good reproduction needs between 200 and 300
> dpi.
> For publishing, BMP, TIF, or EPS are the
> formats of choice for art directors and
> printers.
> After 20 years as a full-time editor, I
> learned the hard way. I hope you don't have
> to.

Actually, monitor screens have different dpi. It may not always be 72 dpi. It depends on the size of the screen and the resolution you are using. I have a 19" crt screen with 1365 X 1024 image area. This nets to a 98 dpi.

I tried 1600 X 1200 but found I could not read most text, so dropped to the lower 1365 X 1024.

I was an Electrical Engineer, specializing in crt displays, before I retired. I have always tried to display the maximum resolution readable (based on a lot of factors including my own eye resolvability) on the display screen.

dan


svry@pacifier.com

I've learned a whole lot from Wayne Fulton's ScanTips website. Just about everything you want to know about the hows and whys of scanning.

http://www.scantips.com/

His book is a goldmine of explanations and examples.

brianf425@yahoo.com

Use PNG format. For one of the best image viewers available, go to http://www.pmview.com - - not available for Linux or Mac.

I'll try to keep this simple. Tiff format is by far the most durable of the images. We handle 100's of files a week for printing and publishing and other formats seem to have "glitches" more often. Your ultimate purpose should determine how you scan. For safety sake, archiving should be done at the highest reasonable resolution in order to reproduce enlarged versions of your images via lithography. (It may not be important now, but if the data is there when you need it, that's a big plus.) The general rule of thumb is scan to a dpi that is 1.5 times the printed lpi (lines per inch of rows of dots use in lithographic printing.) Typical lpi are between 150-300. If you plan to enlarge the pic you will need to scan at the reproduction size at 1.5 times lpi or increase you dpi resolution. Today, png, jpg and even distilled pdf formats of images are all acceptible, but they are best applied to screen viewing and projection.

wyld@sbcglobal.net

Thanks for all the information! I knew this would be the right place.

drs5260fr@yahoo.com