Commons:Graphics village pump/January 2016

Compression and color-shift?

I recently uploaded five images (File:Montebello Vincentino Atelier.jpg, File:La Scuola dei maestri pellettieri di Bottega Veneta.jpg, File:Intrecciato construction.jpg, File:Collaboration Juergen Teller.jpg, and File:Bottega Veneta Boutique.jpg) and noticed there was a slight compression on the uploads, which seems to have resulted in a change in the colors. The uploaded images appear bolder and more saturated than the originals on my drive. Can anyone provide some insight into this and/or help me alleviate this issue?--FacultiesIntact (talk) 01:06, 23 December 2015 (UTC)

Hello FacultiesIntact, I don't really belief that your images get "recompressed" on the upload. What happens here is a scaling, in which JPEG gets extra compression and "extra sharpening" (much more than PNG). What do you see is also depending on your viewer (browser, or graphic-tool, etc..) because there are several (technical) different scaling-methods. I personally have not the power of a colorful monitor, so I see no difference (except the contrast). I guess we can nothing do here. A successful new Year ↔ User: Perhelion (Commons: = crap?)  00:00, 26 December 2015 (UTC)

Perhelion Thanks for the reply. Would uploading these images as PNGs rather than JPGs mitigate the scaling? If I understand correctly, using a lossless format like PNG would help, but not eliminate the problem entirely?--FacultiesIntact (talk) 18:37, 28 December 2015 (UTC)

@FacultiesIntact Generally not, but in your case maybe yes. The PNG have not that much bigger size, try it out. ↔ User: Perhelion (Commons: = crap?)  23:41, 15 January 2016 (UTC)

Inkscape SVG files failing to render on upload

I recently had a computer crash (Windows 7) so uploaded Inkscape V0.91, whereas I had been using an earlier version. Now when uploading *.svg files to Wikimedia Commons, the files upload OK, but fail to render into .png versions with the message: "The upload succeeded, but the server could not get a preview thumbnail". A bug in Inkscape code is under investigation. Summerdrought (talk) 01:04, 15 January 2016 (UTC)

I looked down your upload list (Special:ListFiles/Summerdrought), and the only only missing a thumbnail was File:Sandy Blight Junction Road v116.svg. It turned out to have an indicated height of 0 in the viewBox="..." attribute of the file header, so it's not at all surprising that no thumbnail displayed... AnonMoos (talk) 03:26, 15 January 2016 (UTC)

Thank you AnonMoos. I notice that you have fixed my file File:Sandy Blight Junction Road v116.svg and it renders correctly. I am not familiar with editing XML or similar files, can you explain how you fixed the viewBox parameters please. I have aborted several attempts at uploading, as it happens every time I try with any *.svg file. Summerdrought (talk) 05:31, 15 January 2016 (UTC)

@Summerdrought: As I have described on the Inkscape bug report,[1] there should be no zero value for height and width of the viewBox. It is fully implausible how this could be happen. You can delete the viewBox or better you can calculate the zero value on bill ratio of existing height/width values. Read the also the answers on the bug report. And maybe answer there!? ↔ User: Perhelion (Commons: = crap?)  16:22, 15 January 2016 (UTC)

Further information. I have been successful in uploading new files with the "viewBox = 0 0 xxx xxx" attributes, however there is no thumbnail generated on the upload wizard page, and the message displayed is "The upload succeeded, but the server could not get a preview thumbnail". On going directly to the file page however, the PNG thumbnails are now displaying correctly. Therefore it is possible that Inkscape is not the source of the problem. See this example where the source code contains zero values. https://commons.wikimedia.org/wiki/File:A_test_v0.91_x64.svg. I have a screendump of the upload wizard message saved on a Word document, but I do not know how to display it. Summerdrought (talk) 22:49, 15 January 2016 (UTC)

Yes I can confirm this behavior since some weeks. I mean this is a Wikimedia bug, we should open a Phabricator task. ↔ User: Perhelion (Commons: = crap?)  23:37, 15 January 2016 (UTC)

Summerdrought -- SVG files are basically text (XML). I just opened "File:Sandy Blight Junction Road v116.svg" in a text editor and looked for dubious code... AnonMoos (talk) 02:29, 16 January 2016 (UTC)

AnonMoos - thank you for the information. Before I downloaded Inkscape V0.91 (5 Jan 2016), I was using V0.48. On checking the source code, none of my SVG files prior to that have the viewBox function in the code. After installing V0.91, new files have the viewBox function, so I presume it was a modification post V0.48. It so happens that some of the new files did render OK, and some did not (all with viewBox="0 0 xxx xxx") so I am not sure if the viewBox is the source of the "fail to render". Summerdrought (talk) 02:49, 16 January 2016 (UTC)

Do a text diff on the "03:20, 15 January 2016" and the "03:11, 15 January 2016" versions of "File:Sandy Blight Junction Road v116.svg", and the only difference is in image width and height specifications: AnonMoos (talk) 17:09, 16 January 2016 (UTC)

10c10
<    width="600" height="760" viewBox="0 0 600 760"
---
>    width="169.37366mm" height="214.52921mm" viewBox="0 0 566.92913 0"

• OK, I now see that the final '0' has caused the fail to render. At some stage while drawing the map, I may have done a page resize using the function "Resize page to content", so that could have caused the upload problem. The bug has been addressed here:[2]. Many thanks to all contributors regarding this item. Summerdrought (talk) 21:50, 16 January 2016 (UTC)

How to rotate a large *.tif file?

San-Francisco 1849

I want to know, please: How to rotate a large *.tif file? Due to band width limitation I cannot download/rotate/upload. --NearEMPTiness (talk) 18:19, 21 January 2016 (UTC)

Thanks, now I understand that {{Rotate|90}} should be typed, if the rotate button isn't available. --NearEMPTiness (talk) 20:28, 22 January 2016 (UTC)

However, it turns out that the file is too big to be rotated automatically: {{rotate|nobot=true|reason='''Reason''': File bigger (77961200 B) than limit (20000000 B). Please wait until someone does a lossless(!) fix by hand.|90}}. --NearEMPTiness (talk) 04:44, 23 January 2016 (UTC)

Also, User:Rotatebot only handles JPEG, PNG and GIF files. Anyway, this one is  done. —LX (talk, contribs) 15:30, 24 January 2016 (UTC)

Thank you very much, indeed. --NearEMPTiness (talk) 17:04, 24 January 2016 (UTC)

File displaying strangely

This file is displaying as corrupt as a thumbnail and on the image page, but not on the [3] orignal upload. Any solutions?Nigel Ish (talk) 15:13, 24 January 2016 (UTC)

Yes, use RGB instead of CMYK. —LX (talk, contribs) 15:37, 24 January 2016 (UTC)

I took the liberty of converting it. —LX (talk, contribs) 15:48, 24 January 2016 (UTC)

PNG darkness at preview sizes (2)

File:Kankrin Egor Francevich.png is much darker in the thumbnail [4] as it can be seen in the article ru:Канкрин, Егор Францевич.

Actually the same situation as here Commons:Graphics village pump/July 2015#PNG darkness at preview sizes.

I can`t get how you resolved it. Can anybody fix this please? The-city-not-present (talk) 22:11, 25 January 2016 (UTC)

Ok, probably I did it, converted to grayscale in Photoshop and it is Ok for me now. The-city-not-present (talk) 22:27, 25 January 2016 (UTC)