24bit jpg to tiff file conversion ends up as 8bit b&w

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graemeNPS
Posts: 64
Joined: 2009-01-12T14:25:55-07:00

24bit jpg to tiff file conversion ends up as 8bit b&w

Post by graemeNPS »

Hi,
we use ImageMagick to convert a wide variety of formats to various output formats.
It does a great job of that.
But, every once in awhile....
A customer is complaining that some 24bit RGB jpgs are not consistently converting to 24bit RGB tifs. Some resulting TIF files are 8bit b&w.
I am hoping for some guidance, either for the customer to fix the jpgs, or what we can do to render the tifs consistently as 24bit RGB

I have placed the customer source jpgs and our results in our ftp site:
site:ftp.northplains.com
user:publicforum
pass:543publicforum123
dir:/imagemagick/ts-10381-samplefiles/
or the zip ts-10381-samplefiles.zip at /imagemagick

Any help is much appreciated,
graeme
snibgo
Posts: 12159
Joined: 2010-01-23T23:01:33-07:00
Authentication code: 1151
Location: England, UK

Re: 24bit jpg to tiff file conversion ends up as 8bit b&w

Post by snibgo »

A customer is complaining that some 24bit RGB jpgs are not consistently converting to 24bit RGB tifs. Some resulting TIF files are 8bit b&w.
I suppose the input file is monochrome with less than 256 colours, so IM only needs 8 bits. Try comparing the input and output. Are they identical? If so, then what is the problem?


There are a lot of files in that zip. Can you give an input and output file, and what command made the output?
snibgo's IM pages: im.snibgo.com
graemeNPS
Posts: 64
Joined: 2009-01-12T14:25:55-07:00

Re: 24bit jpg to tiff file conversion ends up as 8bit b&w

Post by graemeNPS »

The problem is that the customer expects the conversion from RGB 24 bit to yield RGB 24 bit.
The results are not identical, in that the color space has changed, and the results are inconistent.
Imagemagick is inconsistent in doing that with this set of jpegs converted to tiff. See the converted(x) directories.

Mogrify and convert gave the same inconsistent results. The source files are the jpegs, the output files are the tiffs in the converted(x) directories. readme.txt tells how the outputs were made.
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magick
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Posts: 11064
Joined: 2003-05-31T11:32:55-07:00

Re: 24bit jpg to tiff file conversion ends up as 8bit b&w

Post by magick »

Add -type truecolor to your command line. Does that solve the problem?
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