Commons:Graphics village pump/December 2012

Cropping jpeg increases file size

I cropped the frame from File:Maker_unknown,_India_-_Krishna_and_Radha_-_Google_Art_Project.jpg to make it a PD image, using jpegcrop on Windows. I didn't notice until I uploaded it that the file size had actually gone up, from 9.52 to 11.18 MB. I loaded the images up on separate layers in difference mode and it seems as though there is no change to the content of the image. Anyone know what causes the change in size? —Moogsi (talk) 22:14, 3 December 2012 (UTC)

Actually I'm going to answer my own question :) I did jpegtran -optimize on the image and that made it smaller than the original. Poking around in the preferences for jpegcrop, the default setting for "Entropy encoding method" is "Huffman default". I imagine changing that to "Huffman optimized" would optimize the file in the same way —Moogsi (talk) 22:29, 3 December 2012 (UTC)

Sometimes if you losslessly transcode from progressive JPEG to non-progressive JPEG, then the size can increase, because certain parameters of the progressive side of the JPEG standard give better compression results than the corresponding parameters of the non-progressive side of the JPEG standard. Obviously not in this case, however (and not usually 15% smaller anyway)... I also use jpegtran -opt -copy all after applying jpegcrop to sometimes reduce filesize ("-copy all" means that metadata is preserved). AnonMoos (talk) 02:31, 4 December 2012 (UTC)

-copy all seems like a good idea, I didn't know about that.. it seems like it's always best to preserve data from an archival standpoint. I actually took the time to rtfm and it turns out you can -copy exif, which preserves only the EXIF data and comment markers, which seems better for some situations (discards thumbnails and extra data added by Photoshop or what have you, which can sometimes be big). Thanks :) —moogsi^(blah) 18:57, 5 December 2012 (UTC)

Inkscape problems

Hello, I was working with this image: File:Bohr atom model Catalan.svg. You will notice two black zones in the upper text. I edited and translated the image with Inkscape. Do you know how to fix this? "Convert to text" doesn't work. I saved the image in Simple SVG. Thank you in advance.--Arnaugir (talk) 15:25, 2 December 2012 (UTC)

Mysterious black rectangles are almost always due to stupid Inkscape "flowtext" nonsense, which I've fixed in many, many files (see also Commons:SVG Check discussed above). I fixed it, but this left the mysterious letters "cre", which I'm not sure are supposed to be there (I can remove those too). AnonMoos (talk) 01:34, 3 December 2012 (UTC)

Yes, can you remove them please?? I know about the flowtext problem, can you tell me how did you fix it for future cases? what I do is just "Text"->"Convert to text", but this time it didn't fix the black rectangles... anyway thank you very much for your help. If you can remove the "cre" letters that would be awesome. Now that we are in it: do you know if in Inkscape there is a way to list all the objects? ie. I can't see those "cre" letters in the image, how will you erase them? --Arnaugir (talk) 12:15, 3 December 2012 (UTC) update: I myself removed "cre" letters.

I fixed the problem by opening the SVG file as text and editing it in a text editor (I very rarely use Inkscape to edit SVG files at all -- only to test and convert SVG files). The official Inkscape method is apparently to "Unflow Text", but it seems that it can be almost impossible to select, unflow, or delete an empty flowed text element within Inkscape (i.e. a "flowtext" without any actual text contained within). AnonMoos (talk) 15:42, 3 December 2012 (UTC)

Thank you very much, will try this next time. Your help is very much appreciated. Cheers--Arnaugir (talk) 11:52, 4 December 2012 (UTC)

Wrong shades of green displaying

I need help with this file—

On my monitor and iPhone, it displays fine, with slightly washed out green. On other monitors it has an ugly bright oversaturated green.—Kelvinsong (talk) 03:09, 6 December 2012 (UTC)

It looks OK on my monitor. If everybody is viewing the SVG in the form of a rendered PNG file, and everybody is viewing the same PNG, then it's hard to see how the problem is at the Wikimedia end. (I downloaded the 622px PNG thumbnail, and it doesn't contain any crazy Gamma or anything.) -- AnonMoos (talk) 05:25, 6 December 2012 (UTC)

Help converting .jpgs to DjVu book format

Need help converting the Cheyenne Catechism .jpgs into book format. Is there someone here who can convert .jpgs to DjVu book format? Djembayz (talk) 17:13, 21 December 2012 (UTC)