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I am told to use TIFF format for my raster images (originally I have both JPEG and PNG images) according to the editorial office of the journal I am submitting a research paper to.

I tried ImageMagick to convert those images to TIFF format:

magick mogrify -format tiff *.{jpg,jpeg,png}

However the resulting TIFF image are all relatively large (approximately, 6.5 times bigger in file size compared to their JPEG/PNG counterparts). the following is an example:

# size  filename
# ==================
36K     image01.jpg
232K    image01.tiff
140K    image02.png
232K    image02.tiff

I have no idea if that is inherent to the TIFF format itself or something else.

Could someone please enlighten me?

Giacomo1968
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Amazigh_05
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    It is utterly pointless trying to up-convert jpgs. If you need tiff [usually because you need a 16-bit colour depth] then you must start in tiff. png will up-convert losslessly, but you can't regain that discarded 8 bits, so your tiff is filling with zeroes. & yes, tifs are huge compared to other formats. If you have 8-bit pngs, use those. Don't use jpgs unless you saved them at 100% quality [in which case they'll be the same size as the pngs]. – Tetsujin Jan 30 '22 at 10:01
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    Quick comparison for sizes - Original 14-bit RAW 23MB, TIFF 130MB, JPG@100% or PNG 12MB. – Tetsujin Jan 30 '22 at 10:04
  • Please edit your question: “I am told to use TIFF format for my raster images…” Who told you to do this? What context was this presented to you? Are you dealing with camera images and want to retain high quality? Are you attempting to create print layouts and someone is criticizing your use of JPEGs? Please clarify. FWIW, a JPEG compressed with 100% quality is effectively the same exact image as a TIFF even if the JPEG format is compressed. Taking a JPEG (compressed format) and converting it to a TIFF (uncompressed) will not improve quality. All it will do is create a very large TIFF file. – Giacomo1968 Jan 30 '22 at 19:21
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    @Giacomo1968: It's in the context of research paper. I will ask the editorial office if JPEG images are accepted.If so, I will switch to using JPEG instead. – Amazigh_05 Jan 31 '22 at 08:47
  • @Tetsujin: Question is if the file size difference is valid. Extra points if you can explain why. – mnemotronic Feb 17 '23 at 20:16
  • @mnemotronic - I've no idea what you mean by 'valid'. Why is because of the number of data points. – Tetsujin Feb 18 '23 at 09:14

1 Answers1

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So I assume your question is “why the hell are TIFF images so huge?”

The answer is relatively simple: They are uncompressed by default. Both JPEG and PNG are compressed image formats with lossy and lossless compression, respectively. When you convert these images to TIFF, you basically “uncompress” them.

If you want to save TIFF images with compression, you can use -compress lzw or -compress zip. It won’t do much and some software may not be able to handle it.

Converting a PNG to TIFF is pointless. You gain nothing (except the additional features of the TIFF image format). You waste some storage space.

Converting a JPEG to TIFF is “fraud”. The quality that was lost when compressing will not return. JPEG artifacts and all will still be there. You waste a lot of storage space.

The advice is probably more along the lines of “work in TIFF until the last minute”, but I disagree with that too. Instead, use your image editor’s native image format. It will also be lossless and support all the important stuff like layers and vector layers and whatnot.

You should also make sure that you do not store intermediary images with lossy compression.

Daniel B
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    +1 This is a very clear and concise answer to the core question here: JPEGs are compressed and converting them to a TIFF adds no value and only results in a larger file size. – Giacomo1968 Jan 30 '22 at 19:17
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    Thank you for your answer. The journal I am submitting my paper to is accepting only vector formats (EPS, PDF) and TIFF/JPEG for raster images (PNG is not accepted). For consistency reason, I prefer using a raster format with high resolution instead. – Amazigh_05 Jan 31 '22 at 08:51
  • @DanielB / I am converting a lot of .tif's, output of ScanTailor, to .png's using ImageMagick, and finding the .png's larger, even after running zopfli intensively. These .tif's are bitonal. The only time I can get the .png's to be smaller, is when the .tif is grayscale. Why would that be? – Diagon Jul 06 '23 at 12:56
  • @Diagon You should ask a new question about that. Comments are not a good place to discuss this. Make sure to include relevant metadata (dimensions, color depth, …) of the TIFF images and the resulting PNG images. Maybe also provide a (cropped) example image. – Daniel B Jul 06 '23 at 13:35