What's the purpose of jpeg compression for tiff files?

Question

Since the purpose of tiff is to have lossless image quality, what's the point of saving a tiff file if you're just going to give is a lossy jpeg compression? Why not cut the middle man out and just save a jpeg?

I guess what I'm trying to ask is what is the difference between a jpeg and a jpeg compressed tiff?

Is there some kind of benefit or reason you want to keep the tiff file extension if losing out on the losslessness?

Answer 1

One of, if not THE, major benefit of a TIF file is that it can have a much higher bit depth than of a JPEG. By definition, all JPEG files MUST be 8-bit files. An 8-bit file has 256 tones from pure black to pure white per RGB channel. The math is that you take 2 to the power of the bits of the file. So 2^8 is 256.

In contrast, a TIF file can be 8 bits (256 tones), 14 bits (16,384 tones), 16 bits (16,384) or even 32 bits (4,294,967,296 tones).



Also, whenever you edit a JPEG, even if all you do you is rotate the image, the file must be compressed again based upon the number of shades of the already compressed image. This will degrade the image but fortunately not by a whole lot. From what I understand (take this with a grain of salt) this doesn't happen with the way TIF files are compressed.

Answer 2

TIFF is a wrapper that supports many types of compression, JPEG included. Yes, it doesn't make much sense to use JPEG compression in a TIFF for the main image.



You can include a JPEG thumbnail in a TIFF if you want. This may be desirable for larger images if your image viewer can extract thumbnails.

Answer 3

Helpful if incomplete:



https://www.cambridgeincolour.com/tutorials/imagetypes.htm

Answer 4

Small files are easier to email assuming you don't have "Dropbox" or something similar.

Answer 5

TIFF files can have compression too, but unlike JPEG files, which always has compression, a TIFF file can be uncompressed. A TIFF file can also be written using 16-bit color space as well.



One more thing. There is no such thing as "lossless" compression. Any compression on an image file causes some degradation. However, in some cases a compressed TIFF file can have less degradation than a JPEG. It depends on the image and the level of compression either file has applied to it.

Answer 6

Not all JPEG compression is lossy.



https://www.adobe.io/content/dam/udp/en/open/standards/tiff/TIFFphotoshop.pdf

https://en.wikipedia.org/wiki/Lossless_JPEG