JPEG and Monochrome

James_dean · 11-09-2005, 05:59 AM

I know there are quality issues if you try to convert any image to jpeg that has less than 16 grey levels. But is it possible to make a monochrome jpeg?.

homey · 11-09-2005, 10:56 PM

It looks pretty crappy but seems to work...
convert -monochrome calvin.jpg mudd.jpg

More options with: convert --help

James_dean · 11-09-2005, 11:22 PM

The result i get is 8bits per pixel which is greyscale.......are u sure your output was 1bpp monochrome?

homey · 11-09-2005, 11:38 PM

Yep, I guess it's grayscale.

identify -verbose mudd.jpg
mudd.jpg JPEG 640x480 PseudoClass 256c 60kb 0.040u 0:01
Image: mudd.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Geometry: 640x480
Class: PseudoClass
Type: Grayscale
Endianess: Undefined
Colorspace: Gray
Channel depth:
Gray: 8-bits
Channel statistics:
Gray:
Min: 0 (0)
Max: 255 (1)
Mean: 0.10625 (0.000416667)
Standard deviation: 4.25284 (0.0166778)

http://www.cit.gu.edu.au/~anthony/graphics/imagick6/

James_dean · 11-10-2005, 04:05 AM

You would not happen to know how i could set the channel depth in a jpeg image i see that image magick tool read the channel depth........

homey · 11-10-2005, 08:49 AM

No, sorry.

James_dean · 11-10-2005, 06:12 PM

No worries.....thanks for your replies.