Non lossy graphic formats

[Ins0mniac]

I want to store high res scanned photos onto a CD.

I need the file format to be non-lossy. But I also want compression.

What format do you suggest?

I've been thinking about either the TIFF or PNG formats.

Please help. Any suggestions?

[MisterBishi]

PNG is apparently the format of choice for people with your needs, although I couldn't tell you why.

[tikdoph]

It pretty much depends on what you're going to do with the pics.

TIFFs are preferable if you're going to be printing the pictures. They use LZW (Lempel Ziv Welch) compression, which should be adequate for storage or transfer. Whenever you scan a picture that you intend to edit, it's always best to save it as a TIFF so as to maintain the original picture quality. Once you've edited/photochopped it and saved the finished product, then save it again as a JPG, which will offer superior compression. I find that saving a JPG with a compression ratio of 90% loses little to no quality, but still gives pretty good compression.

PNGs (Portable Network Graphic), as the name suggests, are better for web based applications. Despite their excellent functionality, they haven't really taken off as a popular graphic format and I wouldn't really recommend the format for storage purposes. It's pretty much a replacement for the GIF format, which only supports 256 colours, whereas PNG also offers transparency and supports truecolour.

[jambo]

Or you could zip .bmp's.

[Ins0mniac]

Originally posted by jambo
Or you could zip .bmp's.

I thought of that. It's a possiblity. But then the computer your using would have to have unzipping program or have it built into the OS, like the new Windows flavours.

I could do it like that. But I can't really be bothered.

[MisterBishi]

I'd say if you need transparency, go with .png, if not go with jpeg at the highest quality setting.

[TK-421]

Haven't tried JP2? Probably not widely supported enough if you are worried about zip not being supported though.

[scathing]

Originally posted by Ins0mniac
I thought of that. It's a possiblity. But then the computer your using would have to have unzipping program or have it built into the OS, like the new Windows flavours.

Unless your target audience is operating in a locked-down operating environment, you could always stick the 1.x MB WinZIP installer onto the CD too.....

Its shareware, so putting the installer (without including any *cough*random*cough* strings in a text file or written on the disc itself) isn't illegal either.

[utopian]

I'm going to vote for PNG as well. Unless you can find a really good zip compression method and want to zip up .bmp files.

If you're doing that, just put winrar/winzip on the CD as well. If you want to go with high quality JP2 files, put the installer for IrfanView on.

[dogwomble]

LZW Compressed TIFF's. They offer lossless compression, have been the standard for non-web-based (mainly print) applications for years and therefore just about evrybody can read them, and they get the file down to a reasonable (although nothing close to JPEG) file sizes.

Avoid JPEGs except as a final output format. Because they are lossy, they are not the best format for editing. If I need to retain quality, I'll use a compressed TIFF (Photoshop now even allows you to save layers in TIFF files so I get all the functionality that I need out of the Photohsop file .. .only smaller) and when I'm done, I export to JPEG.

[Ins0mniac]

Yeah, I ended up using TIFF format.