Unable to create thumbnail for TIFF image with channels

[Ruvan]

Hi all

I've run into an issue with convert.exe on Windows.

We have been using Imagemagick for a couple of years without encountering this issue.

It's this image: http://www.fernando.dk/SEP_12_SBE_box_shot.tif, which has a 2 channels and 3 paths embedded.

I normally create thumbnails like this:

Code: Select all

convert -flatten -strip -geometry 100x100 -colorspace RGB d:\SEP_12_SBE_box_shot.tif d:\output.jpg

And this generates this image:

It should have looked like so: (generated from photoshop)

It's clear that ImageMagick is using the first channel (Alpha 1) and applying that. How do I tell it not to use the channel?

I've tried removing -flatten, -strip and -colorspace. Same result. If I remove the channels, then it works.

Version info:
Os: Windows 7 pro, 64bit.
Imagemagick: 6.6.0-5 2010-03-08 Q16

Thanks in advance,

Ruvan

[snibgo]

"-alpha off" works for me, eg:

Code: Select all

convert SEP_12_SBE_box_shot.tif -alpha off -resize 100x100 -strip x.jpg

Windows 7, 6.6.2-4.

[magick]

ImageMagick currently only supports reading the first TIFF extra-samples as the alpha channel. You could of course add +matte to your command line to remove the alpha channel to get the desired results. To use an extra-sample other than the first, a patch is required to ImageMagick. We'll add it to the list of enhancements but it may be some time before we implement it.

[Ruvan]

"-alpha off" works for me, eg:

Code: Select all

convert SEP_12_SBE_box_shot.tif -alpha off -resize 100x100 -strip x.jpg

Ah, I think it's a combination of -alpha off and -resize, opposed to -geometry

because, -geometry and -alpha off still produces the incorrect.

Many thanks!
/Ruvan