Legacy ImageMagick Discussions Archive

Sorry I wasn't more clear about escaping %s in my first post. When oddness happens in a batch file, it helps to pause at the end or redirect the output so that you are able to examine what command was actually executed after all substitutions were made. You are not the first person to stumble over t...

Did you try
convert source_filename -channel RGBA -contrast-stretch 1%% -quality 100 destination_filename

Thank you for the alternatives, but I really do want a full/maximum contrast stretch of the visible area, for any given image and mask. I have come up with one idea. Use -alpha Background to set all the transparent pixels to a middling color that hopefully won't affect -auto-level by still being a m...

See -page for setting your PostScript page size. Also see:
http://www.imagemagick.org/Usage/formats/#ps

My apologies for being unclear in my first post. I have two input files. One is the image I want -auto-level to work on. The second is a mask, which is black and white (no semi-transparency). The mask is needed because my final image is not square. So I would like -auto-level to stretch the values t...

The % symbol has special meaning in Windows batch files and needs to be escaped to %%.

Thank you for the suggestion, but that didn't help either. The example: convert -size 30x120 gradient:black-white image.png convert -size 30x40 xc:black xc:white xc:black -append mask.png convert image.png mask.png -compose Copy_Opacity -composite -auto-level gk_try.png convert image.png mask.png -c...

I would like to stretch the values in my image to the full range. -auto-level seems to be exactly this. However, I have one complication. My image is not square and so has a second image as a mask (no semi-transparent). -auto-level doesn't appear to accept a mask, so I used Copy_Opacity to merge the...

I second using -profile if applicable. Sometimes color management can matter little, but it makes a huge difference when I convert my grayscale ProPhoto (gamma=1.8 ) photos to sRGB (with its weird gamma curve of about 2.2). I just started using ImageMagick two weeks ago, and largely working in grays...

Writing JPEG Images http://www.imagemagick.org/Usage/formats/#jpg_write Image Type when Reading and Writing http://www.imagemagick.org/Usage/basics/#type Note: Resaving a jpeg is usually a lossy operation. You can do an image compare to see how much (or often little) is lost. Somewhere I saw a tool ...

Maybe try using -type TrueColor instead of -colorspace.

One of our mysteries solved then. I hope you are on the path to what you needed. Providing example images definitely helped in understand your question, so thank you for that.

Well, this is more annoying. I am using version 6.6.5-8 2010-11-10 Q16 on Windows 7. I have been an ImageMagick user for only 2 weeks and so my help is worth what it is, but getting different results is unexpected and unhelpful. What if you set the threshold value to 1, 254, or 65530? Also note that...

Nothing hidden; what you see is what you get. I don't know why the input file order doesn't matter for you, but no problem no worries I guess. The first option is very simple: convert Original.png ( ToRemove.png -channel A -threshold 99% ) -compose dst_out -composite Destination.png Is this sufficie...

#2 why did I have to divide by 17 to get the values to drop into the range 0-15? 255 / 16 = 15.9375 255 / 17 = 15.0000 I guess you get rounding, not an integer division. A shift evaluate would give you different results. What results do you intend? A 0 will stay a 0. A 255 should become a 15. What ...