XnView Software

I don't have a deep understanding of file-formats and compressions and so on, but usually I have the experience with LZW and CCITT:
"Uncompressed TIF has high file size, compression reduces it down to 70-5% file size"

But now I got an uncompressed TIFF (6400 * 4800 pix, 16.400 colors) where I used different "save as tiff .." commands from XNViewMP and got these result:
The file props of the original are: So what's the reason that the compression brings so extreme different results and LZW only a small effect and packbit an increased size?

The file size of a TIFF basically depends on:

o The bit depth (1-bit black and white, 8-bit grayscale or colour [only 24-bit and 32-bit colour supported in xnview software] of the image saved;

o Whether the compression option used is lossless or lossy [I think that all options except JPEG compression are lossless] and the alternative save settings options within the compression option selected;

o The complexity of the image content, some compression options being more efficient for particular forms of image [for example, images with large areas of the same colour, such as in a 1-bit depth image white or black areas].

In general, file sizes for colour or grayscale images will be much larger if any option other than JPEG compression is selected.

In general, for 1-bit black and white images Fax [CCITT G4] compression is very efficient, although alternative options may result in smaller file sizes for particular types of images.

Can anyone correct any of those guidelines or add other useful information?

Hi cday

I always had the idea (the illusion?) that TIFF is lossles. But is it correct that a JPEG compression result in a JPEG, in the package of a TIFF?

Peter2 wrote: Sat Mar 15, 2025 9:38 am I always had the idea (the illusion?) that TIFF is lossless. But is it correct that a JPEG compression results in a JPEG, in the package of a TIFF?

A JPEG compression algorithm is used, so in effect yes, whether that matters will depend on the particular use case....

I don't immediately see a situation where saving an image as a TIFF with JPEG compression would have an advantage over saving directly to a JPEG file, which would actually slightly increase the file size, but maybe there are some cases?

Edit: There is also the question of the JPEG save options used, as they are not directly accessible when saving to a TIFF, whether XnView's normal configurable options or fixed settings are used,which might result in a non-optimal image due to quality or larger file size than actually needed?

Thanks @cday,

and have a fine weekend.

https://en.wikipedia.org/wiki/TIFF#Details wrote:TIFF is a flexible, adaptable file format for handling images and data within a single file, by including the header tags (size, definition, image-data arrangement, applied image compression) defining the image's geometry. A TIFF file, for example, can be a container holding JPEG (lossy) and PackBits (lossless) compressed images. A TIFF file also can include a vector-based clipping path (outlines, croppings, image frames). The ability to store image data in a lossless format makes a TIFF file a useful image archive, because, unlike standard JPEG files, a TIFF file using lossless compression (or none) may be edited and re-saved without losing image quality. This is not the case when using the TIFF as a container holding compressed JPEG. Other TIFF options are layers and pages.

https://libtiff.gitlab.io/libtiff/specification/index.html wrote:Draft DRAFT TIFF Technical Note #2 covers problems with the TIFF 6.0 design for embedding JPEG-compressed data in TIFF, and describes an alternative.

• AWare Systems: TIFF File Format FAQ
• FileFormat.Info: TIFF File Format Summary → JPEG Compression

Software for analyzing TIFF files:

• AWare Systems: AsTiffTagViewer
• LibTIFF: TIFF Tools → Windows binaries