Search found 15 matches

by jhuckaby
2013-04-05T16:14:17-07:00
Forum: Bugs
Topic: Color reduction doesn't work well with alpha PNGs
Replies: 6
Views: 5887

Re: Color reduction doesn't work well with alpha PNGs

Ah, thank you fmw42, I did not know that could be used with the 'Quantize' filter. I'll play around with it.
by jhuckaby
2013-04-05T15:30:07-07:00
Forum: Bugs
Topic: Normalize filter does not work anymore
Replies: 10
Views: 7108

Re: Normalize filter does not work anymore

Thanks guys. Adding "-colorspace RGB" seems to be the universal solution to all my recent issues, haha.
by jhuckaby
2013-04-05T15:23:24-07:00
Forum: Bugs
Topic: Color reduction doesn't work well with alpha PNGs
Replies: 6
Views: 5887

Re: Color reduction doesn't work well with alpha PNGs

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...
by jhuckaby
2013-04-05T11:53:51-07:00
Forum: Bugs
Topic: PerlMagick: Cannot use colorspace to correct dark gray imgs
Replies: 0
Views: 2811

PerlMagick: Cannot use colorspace to correct dark gray imgs

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 colorspa...
by jhuckaby
2013-04-05T09:19:28-07:00
Forum: Bugs
Topic: Normalize filter does not work anymore
Replies: 10
Views: 7108

Normalize filter does not work anymore

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...
by jhuckaby
2013-04-05T09:02:19-07:00
Forum: Bugs
Topic: Color reduction doesn't work well with alpha PNGs
Replies: 6
Views: 5887

Color reduction doesn't work well with alpha PNGs

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...
by jhuckaby
2013-04-02T18:41:43-07:00
Forum: Bugs
Topic: ImageMagick 6.8.4 darkening grayscale images on convert
Replies: 22
Views: 23535

Re: ImageMagick 6.8.4 darkening grayscale images on convert

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...
by jhuckaby
2013-04-02T17:58:45-07:00
Forum: Bugs
Topic: ImageMagick 6.8.4 darkening grayscale images on convert
Replies: 22
Views: 23535

Re: ImageMagick 6.8.4 darkening grayscale images on convert

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...
by jhuckaby
2013-04-02T17:00:06-07:00
Forum: Bugs
Topic: ImageMagick 6.8.4 darkening grayscale images on convert
Replies: 22
Views: 23535

Re: ImageMagick 6.8.4 darkening grayscale images on convert

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( '...
by jhuckaby
2013-04-02T15:23:47-07:00
Forum: Bugs
Topic: ImageMagick 6.8.4 darkening grayscale images on convert
Replies: 22
Views: 23535

Re: ImageMagick 6.8.4 darkening grayscale images on convert

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...
by jhuckaby
2013-04-02T12:05:32-07:00
Forum: Bugs
Topic: ImageMagick 6.8.4 darkening grayscale images on convert
Replies: 22
Views: 23535

ImageMagick 6.8.4 darkening grayscale images on convert

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...
by jhuckaby
2013-04-01T09:51:15-07:00
Forum: Users
Topic: Gif manipulation side effect?
Replies: 11
Views: 8254

Re: Gif manipulation side effect?

Confirmed fixed in 6.8.4-5! Thanks so much!
by jhuckaby
2013-03-29T10:38:38-07:00
Forum: Users
Topic: Gif manipulation side effect?
Replies: 11
Views: 8254

Re: Gif manipulation side effect?

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).
by jhuckaby
2013-03-29T10:20:55-07:00
Forum: Users
Topic: Gif manipulation side effect?
Replies: 11
Views: 8254

Re: Gif manipulation side effect?

Addendum: I just tried with the latest build (ImageMagick 6.8.4-4 as of March 29, 2013) and the bug still exists.
by jhuckaby
2013-03-29T09:53:24-07:00
Forum: Users
Topic: Gif manipulation side effect?
Replies: 11
Views: 8254

Re: Gif manipulation side effect?

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...