Converted TIF has bigger file size than JPG

[sweengau]

Hi All,

I have been using the command below to convert color JPG to Black and white TIF. The conversion is successful. But the file size of the Black and white still bigger than JPG. Base on the same document which scanned in Black and white, the file size of TIF is less than 100KB. But the converted TIF has file size more than 300KB.

Below is the command used.
convert -type bilevel -monochrome -compress Group4 -depth 2 0001_color.jpg 0001_1bit.tif

Question:
1. Why the file size of the converted TIF is bigger than JPG even I have used Group4 compression?
2. How to reduce the file size of converted TIF to around 100K for 300DPI group4 compression TIF image?

Below is the link of the 300 DPI colour JPG and converted TIF in Black and white.
https://www.dropbox.com/sh/o5pb3o51ux5n ... W59ha?dl=0

[fmw42]

try using proper IM syntax where the input file is read first.

Code: Select all

convert 0001_color.jpg -monochrome -compress Group4 0001_1bit.tif

What is your IM version and platform?

JPEG is a lossy compression that works to make very small file sizes for nearly constant patches of a given color. It is questionable that group4 tiff will be smaller. I would have to test.

I get 198 KB for the JPG and 305 KB for the tiff with my command above and IM 6.9.6.4 Q16 Mac OSX>

[fmw42]

If you add +dither, the file size is reduced further to 47 KB.

Code: Select all

convert 0001_color.jpg +dither -monochrome -compress Group4 0001_1bit2.tif