Legacy ImageMagick Discussions Archive

Ah, thank you fmw42, I did not know that could be used with the 'Quantize' filter. I'll play around with it.

Thanks guys. Adding "-colorspace RGB" seems to be the universal solution to all my recent issues, haha.

Hey snibgo, Thanks! I did see that command-line trick in the ImageMagick Quantize docs, however, it produces a much larger file size: Original 32-bit PNG: 10.6K Converted 8-bit PNG: 5.4K With the -alpha off -alpha on thing: 7.8K I was hoping to keep the size down, but the quality up, like ImageMagic...

Hello, I recently posted this topic regarding darkening grayscale images: http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=23092 The workaround I was told, as per http://www.imagemagick.org/discourse-server/viewtopic.php?f=4&t=21269 introduced in IM 6.7.7-8, is to convert the ...

The ImageMagick 'Normalize' filter works perfectly in ImageMagick 6.3. Here are some shining examples of how well it corrects bad brightness and contrast in images: Source Image #1 (too bright): https://dl.dropbox.com/u/4585115/imagemagick/car-bright-source.jpg Source Image #2 (too dark): https://dl...

Consider this sample 32-bit alpha PNG image: https://dl.dropbox.com/u/4585115/imagemagick/alpha-source.png When converted to 256 colors, ImageMagick 6.3 does a fantastic job: convert alpha-source.png -dither None -colors 256 alpha-256-im63.png ImageMagick 6.3 Output: https://dl.dropbox.com/u/4585115...

fmw42: Thank you very much for that explanation. It makes sense to me now. I had no idea about the gamma setting in the image. If you could, please tell me how to correctly set the colorspace back using PerlMagick. I cannot get that to work no matter what I try, using the same source image: use Imag...

fmw42: Sure thing, here is the simplest test case: Download this image: https://dl.dropbox.com/u/4585115/imagemagick/gray_ramp.jpg Run this command: convert gray_ramp.jpg output.jpg Try to view output.jpg. It will be much darker than the original. In fact, you will see that most of the shades of gre...

fmw42: I'm sorry to report, the bug still exists in IM 6.8.4-6. snibgo: Thank you, that does work around the problem on the command line (I had the syntax wrong before). However, I cannot seem to make this work using Perl Image::Magick: use Image::Magick; my $img = new Image::Magick(); $img->Read( '...

fmw42: Adding -colorspace RGB has no effect. The images are still very dark. I tried it on the command line, as well as in the Perl script. The forum you linked to is talking about changes made in ImageMagick 6.7.7-8. This bug I am talking about here is much more recent, introduced in IM 6.8.4. Imag...

Hello, ImageMagick 6.8.4 seems to be significantly darkening my grayscale images, when I simply run them through 'convert'. Consider these two sample grayscale images: https://dl.dropbox.com/u/4585115/imagemagick/gray_ramp.jpg https://dl.dropbox.com/u/4585115/imagemagick/rgb-desaturated.jpg When I s...

Confirmed fixed in 6.8.4-5! Thanks so much!

Addendum 2: I cannot reproduce the bug using ImageMagick 6.8.2-10. So it was introduced sometime between 6.8.2-10 (Feb 12) and 6.8.3-10 (March 18).

Addendum: I just tried with the latest build (ImageMagick 6.8.4-4 as of March 29, 2013) and the bug still exists.

I can confirm this is happening for me as well, using any number of different interlaced GIF89a images. It only seems to happen if the GIF is interlaced. I am using ImageMagick 6.8.3-10 (Q8) on CentOS 6.2 (64-bit). To reproduce, download one of the following interlaced GIF 89a images: https://dl.dro...