Search found 1945 matches
- 2014-07-29T23:59:40-07:00
- Forum: Users
- Topic: [SOLVED]Windows script driving IM: basic arithmetic on param
- Replies: 5
- Views: 7028
[SOLVED]Windows script driving IM: basic arithmetic on param
Bart van der Wolf, with some assistance from Fred Weinhaus, Alan Gibson and myself, has been polishing a Windows script that combines several ImageMagick commands to produce excellent quality when resizing. (Right now, it only works "perfectly" with sRGB input and output, but this may be e...
- 2014-07-25T06:29:39-07:00
- Forum: Digital Image Processing
- Topic: BC-splines with 2C+B=1 are optimal for EWA resampling
- Replies: 41
- Views: 147924
- 2014-07-23T02:43:53-07:00
- Forum: Digital Image Processing
- Topic: minimize resize halo by luminance-weighted gamma blending
- Replies: 6
- Views: 29123
Re: halo minimization by luminance-weighted gamma blending
This viewtopic.php?f=1&t=25945#p113621 and some of the preceding posts in the same thread are relevant to this subject.
- 2014-07-22T18:07:26-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
Fred: This is what's going on: Indeed, one could do a resize in sRGB then convert to linear RGB, convert to linear RGB then resize, compute the luminance from the latter, blend the two results, and convert the blend back to sRGB. What I showed was actually exactly the same replacing sRGB by Adobe RG...
- 2014-07-22T16:33:50-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
If I understand correctly how profiles etc are handled with IM, and assuming input_small.tif is Adobe RGB 8 bit (if already 16 bit, I imagine the first parentheses can be skipped) this would be the one in which linear is blended with a gamma version which here is neither 2 nor 3. This is different t...
- 2014-07-22T15:22:51-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
Fred: When I have a minute, I'll post a simplified version that exploits the fact that we may as well use gamma 2.19921875 intead of gamma 2 or 3.
(It's already tomorrow where I live.)
(It's already tomorrow where I live.)
- 2014-07-22T11:57:27-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
Alan: I'm totally fine with "different RGB colorspaces". Actually, I'd be fine with other primaries than RGB. So this works for >>me<<. But indeed, without the "Longer answer", people may think that they are getting the same linear RGB as doing -set colorspace sRGB -colorspace RG...
- 2014-07-22T10:02:47-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
So, to go from Adobe RGB to linear RGB with Adobe RGB primaries(with possibly a -set colorspace RGB or two to avoid confusion) and to go back to Adobe RGB
Code: Select all
... -gamma .4547069271758437 ...
Code: Select all
... -gamma 2.19921875 ...
- 2014-07-22T04:22:31-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
Re: convert from Adobe RGB to some kind of linear RGB (and b
Alan (snibgo):
Cool: Adobe RGB is a "straight" gamma space \o/
Cool: Adobe RGB is a "straight" gamma space \o/
- 2014-07-20T02:07:16-07:00
- Forum: Users
- Topic: convert from Adobe RGB to some kind of linear RGB (and back)
- Replies: 19
- Views: 22522
convert from Adobe RGB to some kind of linear RGB (and back)
How can this be done? Looked at http://www.imagemagick.org/Usage/formats/#color_profile and am not 100% sure I got the full picture. If the profile is embedded in InputImage, is convert InputImage -profile (stuff I want to do in linear RGB) OutputImage enough? I don't particulary care which linear R...
- 2014-07-18T01:29:02-07:00
- Forum: Digital Image Processing
- Topic: minimize resize halo by luminance-weighted gamma blending
- Replies: 6
- Views: 29123
minimize resize halo by luminance-weighted gamma blending
As discussed initially in http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=25736 and http://www.imagemagick.org/discourse-server/viewtopic.php?f=22&t=21804#p89728 and further developed in http://www.luminous-landscape.com/forum/index.php?topic=77949.msg745796#msg745796 and htt...
- 2014-07-16T05:07:14-07:00
- Forum: Users
- Topic: Improving sigmoidal image resampling (enlargement)
- Replies: 19
- Views: 31392
- 2014-07-15T11:25:55-07:00
- Forum: Users
- Topic: Improving sigmoidal image resampling (enlargement)
- Replies: 19
- Views: 31392
- 2014-07-15T00:36:24-07:00
- Forum: Users
- Topic: Improving sigmoidal image resampling (enlargement)
- Replies: 19
- Views: 31392
Re: Improving sigmoidal image resampling (enlargement)
Preliminary findings I am pretty sure that sigmoidization is dead as a general purpose resampling method. The simple version of what works better is to use mapping through a gamma space (with a matching pair of -gamma commands, like -gamma 3 -distort Resize 800% -gamma .33333333333333 ) to reduce t...
- 2014-07-09T23:37:55-07:00
- Forum: Announce
- Topic: Windows/Linux/OSX ImageMagick GUI
- Replies: 9
- Views: 128194
Re: Windows/Linux/OSX ImageMagick GUI
Will it try to load and save as 32-bit float tiff? Whatever it loads (unless a depth command is issued?) will generally be stored, internally, in a floating point format. If this is not acceptable, stick to the standard Q16 version. There may be ways of controlling this behavior, but I don't have t...