This goes back to a change log entry
2012-08-16 6.7.9-1 Cristy <quetzlzacatenango@image...>
Don't colorize alpha channel if it is not active (reference viewtopic.php?f=3&t=21547
Which references a bug report I made (viewtopic.php?f=3&t=21547
I believe the end result was to make it like it is today. At least the test in my last post on that topic confirm that it was working this way after the bug fix in the specified release. Though it may have more to do with being able to enable the alpha channel after turning it off and colorizing than with -colorize. Thus -colorize may have been working this way even before that release.
Doing some release testing:
convert logo: -transparent white -fill red -colorize 100% x:
kept the transparency as Anthony had expected up to 18.104.22.168
But then afterwards, up to 22.214.171.124 (when I submitted the bug report), it was making everything totally red (and turning on and off channels did not allow the transparency to be kept). After the bug report (126.96.36.199), it still keeps everything red, but allows the alpha channel to be turned off and on so as to preserve the transparency.
So it has made the image fully opaque red, since 188.8.131.52 (about 90 versions)
I have been making my scripts conform to this post 184.108.40.206 way -colorize works.
But I suppose that it could be changed back to the pre 220.127.116.11 processing so that it kept the alpha channel unchanged when colorizing. So long as I can still do the same with
convert partiallytransparentimage -alpha off -fill red -colorize 100% -alpha on show:
and can make the image totally red by
convert partiallytransparentimage -alpha opaque -fill red -colorize 100%
I suppose I could go along with that.
But lets hear back from Anthony (and anyone else).