Is TIFF really of higher quality than PNG-24?

  • I've been doing some research to try to figure out why more people do not store high-resolution image files as PNG-24. PNG has exactly-reversible, lossless compression, it is a net-friendly format so any web browser can view it, and it supports full transparency.

    I've seen several people say that TIFF has a "higher quality" than PNG, but no one provides any details on exactly how it is of higher quality. PNG-24 is lossless, so when you "Save As" a TIFF to a PNG, how exactly are you losing quality?

    Define *higher quality*. Does loosing color profile means lower quality? Loosing metadata? Sharpness? Color depth?

    @takeshin, Zzz, when people talk about images, "higher quality" of course refers to image quality. What else would it be? If the computer displays FileA using the same pixels as it does with FileB, then we can say that the two files have identical image quality.

  • You explicitly mentioned PNG-24 - that has eight bits per channel, whereas a TIFF file can have 16. That would be one reason the quality could be higher, from a RAW conversion especially but also if you are doing a lot of editing.

    The PNG standard also supports 16-bits per channel (PNG-48) but I don't know how many applications support that, whereas pretty much anything that can read TIFF is going to be able to read a 16-bit TIFF file.

    TIFF can also store layers in it, which is not a quality issue so much as a flexibility thing. PNG is really meant to hold an image, not a layered set (although APNG can hold a set, it's really not for the same purpose).

    One additional bit of practical information is that TIFF can store many kinds of Photoshop layers, I have used it for images which had a number of adjustment layers applied. That is not possible with PNG, you would have to flatten the whole image.

    In fact, channels in TIFF files can be in any IEEE 754 floating-point format too, including the 128 bit one, for 384 bits (48 bytes) per pixel in the RGB, YCbCr and CIE L*a*b* formats and 512 bits (64 bytes) per pixel in the CMYK format. Same applies to any alpha channel, if present, as well as potentially non-visible channels (satellite images are often full of IR channels in different bands, for example).

    Equally TIFF files can also be group 3 fax. Why must people continually conflate the container format with the format contained within it...

    @Kendall, So what's the quality difference between TIFF-58 and PNG-48? Do they produce the exact same pixels on screen?

    @Pacerier TIFF-58 (is there such a standard? or do you mean 16-bit TIFF files?) will look no different on screen (or print) than a PNG 48, both are lossless. It's just that more applications will be able to open the TIFF.

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Content dated before 7/24/2021 11:53 AM