TIFF vs PNG

[ozczecho]

Hi all,

I am just wondering what does TIFF format give you that PNG doesnt? At the moment I use PNG to store my digital stills after PP, but have noticed a lot of people here use TIFF...

Thanks

ozczecho

[stubbsy]

Well - to start with TIFF is lossless whereas PNG is lossy - so converting to png (like jpeg) loses data everytime you save as jpg. That's why the file sizes are so different.

As an aside NEF is lossy too (there's an article linked to here about this somewhere), but not very much!

[sirhc55]

PNG is normally a web saving format that was intended to replace the GIF format. Three advantages over GIF: alpha channels, gamma correction and two dimensional interlacing.

Actually PNG is lossless compression and supports 48-bit colour or 16-bit greyscale - restoring and resaving will not degrade the image although I would still prefer to save in the TIF format.

[xorl]

PNG and TIFF are both lossless formats. PNG is compressed which is why the output size varies. You can load/save lossless formats as much as you want without degredation. TIFF also supports compression but many applications have compaitibly/support issues with compressed TIFFs. TIFF supports EXIF frames. PNG doesn't, although I believe there is a spec out there to add EXIF support.

Generally I save final PP'd images as JPEGs. If I'm planning to edit them further I'll use XCF (Gimp's native format w/layer support) or PNGs. For printing at a minilab I would use TIFF and skip JPEG altogether. In general, PNG isn't supported by minilabs.

[ozczecho]

Yeah, I was always under the impression that PNG is lossless, what I didnt realise is that it doesnt save the exif info, which would be nice...I never really cared about exif, until now with the D70....

One reason i picked png over tiff was the size difference. Why do you prefer to save in tiff sirhc55 ?

[Alex]

Also, does PNG have an advantage of saving layers?

Alex

[xorl]

TIFF supports multiple layers but not many applications implement it. As far as I know, PNG doesn't support layers.

If you want to store layer information I'd recommend saving the files in your graphic program's native format, Eg XCF for Gimp, & PSD for Photoshop.