Search found 21874 matches

by fmw42
2017-10-21T22:18:36-07:00
Forum: Bugs
Topic: Incorrect use of user-defined channels converting PSD files
Replies: 19
Views: 5711

Re: Incorrect use of user-defined channels converting PSD files

As I understand it, as it is today, IM treats the extra channel in the PSD file as an alpha channel (transparency). If as you say, PS turns off the extra channel when it closes the file and IM did not do this, then there would be no way to save the transparency (alpha channel) when convert to a PNG ...
by fmw42
2017-10-21T19:43:08-07:00
Forum: Bugs
Topic: Grayscale Linear vs Non-linear documentation Bug
Replies: 1
Views: 35

Grayscale Linear vs Non-linear documentation Bug

At https://legacy.imagemagick.org/script/color-management.php and https://www.imagemagick.org/script/color-management.php Normally, the conversion to separate each channel of an sRGB color image produces separate linear grayscale images. However the same concept can be applied, if it is desired to k...
by fmw42
2017-10-21T19:36:58-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

Normally, the conversion to separate each channel of an sRGB color image produces separate linear grayscale images. However the same concept can be applied, if it is desired to keep the separate channels as non-linear grayscale. For example, the following produces non-linear grayscale channels. con...
by fmw42
2017-10-21T17:18:50-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

Where are you reading your quote about linear grayscale. That was during a time from about 6.7 - 6.8.5. It could be still a remnant in 6.8.9, but I thought that version was past it. This works fine for me on IM 6.9.9.20 Q16 Mac OSX, since IM assumes non-linear grayscale and -separate and -combine as...
by fmw42
2017-10-21T16:17:42-07:00
Forum: Bugs
Topic: Incorrect use of user-defined channels converting PSD files
Replies: 19
Views: 5711

Re: Incorrect use of user-defined channels converting PSD files

Please note that IM has limited capabiities with regard to PSD file. Currently, it does not know about extra channels in PSD files or TIFF files. However there has been some effort to develop the capability for TIFF files, but it is not complete. No effort has been made yet to my knowledge for PSD f...
by fmw42
2017-10-21T16:14:59-07:00
Forum: Bugs
Topic: Incorrect use of user-defined channels converting PSD files
Replies: 19
Views: 5711

Re: Incorrect use of user-defined channels converting PSD files

I got your attachments from dropbox. Reviewing with GIMP. Your PSD file shows the second character as a tomato with white background with the extra channel off. It shows the second character as a reddish tomato with a mostly reddish background when the extra channel is on. Your PNG file shows the se...
by fmw42
2017-10-21T14:47:43-07:00
Forum: Bugs
Topic: Incorrect use of user-defined channels converting PSD files
Replies: 19
Views: 5711

Re: Incorrect use of user-defined channels converting PSD files

I still do not understand. What is going wrong? What is currently happening when you convert a PSD with extra channels to PNG or JPG? Does it include the extra channels in the PDS flattened [0] layer or is it corrupt in some way? Perhaps it would be best if you provide a PSD file that has an extra c...
by fmw42
2017-10-21T13:15:51-07:00
Forum: Bugs
Topic: Incorrect use of user-defined channels converting PSD files
Replies: 19
Views: 5711

Re: Incorrect use of user-defined channels converting PSD files

When you convert the psd file to png or jpg, what should happen to the extra channels and what is currently happening that is not correct.
by fmw42
2017-10-21T11:17:57-07:00
Forum: Users
Topic: I don't understand color calculation [solved]
Replies: 7
Views: 109

Re: I don't understand color calculation

'((u[1]*255/231-u[0]/u[1]*255/231+u[0])+1)/2
Parenthesis problem. Divides happen before adds or subtracts. In the above you have u[0]/u[1] which is not what you want. So you need to put paretheses around your subtracts before dividing.

Code: Select all

'((u[1]*255/231-u[0])/(u[1]*255/231+u[0])+1)/2
by fmw42
2017-10-21T10:30:30-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

Where does logo.gif come from? These all work for me. convert logo: -channel b -separate -colorspace RGB logo.tif convert logo.tif -channel b -separate -set colorspace RGB -rotate 90 test1a.tif or convert logo.tif -channel b -separate -set colorspace RGB -rotate 90 -colorspace RGB test1b.tif or conv...
by fmw42
2017-10-20T18:01:53-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

If you separate and then combine, you need to tell IM what the colorspace is before combining and change it to what you want afterwards or it will assume sRGB. convert image1 image2 image3 -set colorspace <whatever it is> -combine -colorspace <whatever you want> result see http://www.imagemagick.org...
by fmw42
2017-10-20T11:07:13-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

That is possible. IM assumes that it is non-linear, I believe, since gamma does not seem to be stored in the TIFF meta data. You can see this by comparing the output from: convert logo: logo.tif and convert logo: -colorspace RGB logo.tif The latter will be darker since the data is actually linear. B...
by fmw42
2017-10-20T10:57:17-07:00
Forum: Users
Topic: I don't understand color calculation [solved]
Replies: 7
Views: 109

Re: I don't understand color calculation

try adding 1 and dividing by 2, so that the range is 0 to 1.
by fmw42
2017-10-20T09:58:40-07:00
Forum: Users
Topic: input Linear RGB specifiy output RGB or sRGB
Replies: 14
Views: 273

Re: input Linear RGB specifiy output RGB or sRGB

I do not think TiFF supports linear RGB. See https://www.awaresystems.be/imaging/tiff/tifftags/photometricinterpretation.html. convert logo: -colorspace RGB logo.tif identify -verbose logo.tif Colorspace: sRGB Gamma: 0.454545 Using -set colorspace, just sets a colorspace flag to tell IM what the col...
by fmw42
2017-10-20T09:34:41-07:00
Forum: Users
Topic: I don't understand color calculation [solved]
Replies: 7
Views: 109

Re: I don't understand color calculation

try (u[2]-u[0]) / (u[2]+u[0]) If the index can be negative, then you need to use HDRI imagemagick and file format such as PFM or TIFF that supports negative values. Or as snibgo said, add a bias of 0.5. Also convert d0-0.png d0-1.png d0-2.png -fx '(u[2])-(u[0]) / (u[2])+(u[0])' d0ndvi.png You do not...