Search found 19 matches

by Albert25
2016-10-24T03:51:55-07:00
Forum: Users
Topic: 48 bit tiff: no-op convert results in pixel noise
Replies: 11
Views: 6855

Re: 48 bit tiff: no-op convert results in pixel noise

Also Debian bug 818360 which suggests the same workaround for Debian Jessie: installing the 4.0.6 version from Stretch:

Code: Select all

wget ftp://ftp.debian.org/debian/pool/main/t/tiff/libtiff5_4.0.6-2_amd64.deb
dpkg -i libtiff5_4.0.6-2_amd64.deb
by Albert25
2015-05-27T12:43:34-07:00
Forum: Users
Topic: how to speed up convert with label?
Replies: 7
Views: 4010

Re: how to speed up convert with label?

Well, it looks like there is no simple rule to remember and use when needed. For my label test, -quality 18 is almost two times slower than -quality 21. So apparently, it must depend on the image content. But it's good to know that this is worth experimenting with before starting a convert of thousa...
by Albert25
2015-05-27T06:55:58-07:00
Forum: Users
Topic: how to speed up convert with label?
Replies: 7
Views: 4010

Re: how to speed up convert with label?

Nice tip about -quality. I wasn't aware of that, and indeed, "-quality 21" makes .png creation twice as fast as the default.
by Albert25
2015-05-27T05:56:18-07:00
Forum: Users
Topic: how to speed up convert with label?
Replies: 7
Views: 4010

Re: how to speed up convert with label?

In case anyone is interested, here is what I found after playing with it for a while. The different image formats give very different speed results. * PNG is very slow, but makes the smallest files * TIFF uncompressed is fast, but makes huge files * TIFF compressed slows down proportionally to the c...
by Albert25
2015-05-20T06:36:46-07:00
Forum: Users
Topic: how to speed up convert with label?
Replies: 7
Views: 4010

how to speed up convert with label?

I'm generating pictures with text on a neutral background, to convert to video. Originally, I used something like this: time for i in `seq 0 50 `; do \ convert -background "#666666" -fill "#99CCFF" -font "$font" \ -size 1920x1080 -gravity center -pointsize $((1080/8)) \ label:"image $i" $(printf "te...
by Albert25
2015-05-16T10:22:43-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

Just in case someone comes across this thread through Google, there is a newer version of the "any2srgb" script here: http://alma.ch/scripts/linux/any2srgb
by Albert25
2012-11-20T17:54:18-07:00
Forum: Digital Image Processing
Topic: Convert 3D LUT to hald image
Replies: 35
Views: 78442

Re: Convert 3D LUT to hald image

I do understand what the 1D and 3D LUTs do. The Wikipedia page is a good start. But that page then leads to trilinear interpolation , which seems to be mathematics quite beyond the level I left school with (or maybe not, but I should have listened more carefully instead of concentrating on the girls...
by Albert25
2012-11-20T15:47:09-07:00
Forum: Digital Image Processing
Topic: Convert 3D LUT to hald image
Replies: 35
Views: 78442

Re: Convert 3D LUT to hald image

What tools do you have to process images with your existing LUTs? None. That is my problem. As far as I know, GIMP cannot import a text LUT and apply it to an image. (Or can it?) What is the format of your lut? Is it an image or just text? Text files in various formats. For example "After Effects" ...
by Albert25
2012-11-20T08:07:20-07:00
Forum: Digital Image Processing
Topic: Convert 3D LUT to hald image
Replies: 35
Views: 78442

Re: Convert 3D LUT to hald image

Maybe I could convert the hald image to a text representation of RGB values of each pixel? (Can IM do that? Some other tool?) So I could get the hald image in text form, modify the values using my LUT, and convert back to a hald-with-lut.png image?
by Albert25
2012-11-11T04:01:52-07:00
Forum: Digital Image Processing
Topic: Convert 3D LUT to hald image
Replies: 35
Views: 78442

Convert 3D LUT to hald image

I have stills extracted from Alexa LOG-C material, and would like to apply a 3D (or 1D) LUT to them. ImageMagick can take a hald image and apply that. But how do I make the hald.png image I want? I can get various LUT file formats from the Alexa LUT Generator . I don't have any of the proprietary so...
by Albert25
2010-07-04T01:29:21-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

Can you give me a hint on what specific aspect you feel needs "better script writing"? If something specific can make the script more portable, or if comments are unclear for you, or there is something else you think needs to be improved, I would be happy to use your advice. If it is to add more opt...
by Albert25
2010-06-22T03:54:12-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

In case it's useful to others coming across this thread, here is a script with plenty of comments, which should be easy to adapt to various needs: #!/bin/bash ## convert (essentially from AdobeRGB or CMYK) to sRGB jpg ## and optionally resize # paths to profile files srgb=/docs/photos/icc/sRGB.icm c...
by Albert25
2010-06-20T05:58:38-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

You might either remove -profile "$profile", or precede it with +profile '*'. That's the part that was both quite clear in the documentation, and also clearly explained in this thread. I somehow still managed to make that mistake. Must have been really too late for me last night... You could compar...
by Albert25
2010-06-19T15:52:15-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

Yes, it does change the colors, and also the brightness and contrast. Using a different cmyk profile also changes the brightness and contrast. I tried USWebCoatedSWOP and USWebUncoated. I will have to go watch the movie to know which is the "correct" conversion. Anyway, here is the temporary script ...
by Albert25
2010-06-19T13:37:43-07:00
Forum: Users
Topic: Converting anything to RGB correctly
Replies: 45
Views: 83666

Re: Converting anything to RGB correctly

I uploaded one of my originals and the various conversions here: http://freneticfilms.ch/temp/cmyk/ Firefox displays the original exactly like the simple -colorspace RGB conversion (but of course IE doesn't display it at all, which is why I'm here, bothering you all for help learning this stuf). Tha...