TIFs appear less focused than JPG equivalent
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Description

Author: M8R-udfkkf

Description:
It appears that TIFs are slightly less focused (more blurred) than their JPG equivalent.

My bot uploaded these two files:

https://commons.wikimedia.org/wiki/File:071017_NRCS_Sterling_003_-_Ohio_%28717110%29%28NRCS_Photo_Gallery%29.tif

https://commons.wikimedia.org/wiki/File:071017_NRCS_Sterling_003_-_Ohio_%28717110%29%28NRCS_Photo_Gallery%29.jpg

The JPG one was converted from the tif with imagemagick (python):
call(['convert', 'currentfile.tif','-quality', '97', 'currentfile.jpg'])

Although the jpg is 97% of the tif quality, it appears to have better quality.

Am I mistaken or is there a reason for this?


Version: 1.21.x
Severity: normal

bzimport added a subscriber: wikibugs-l.
bzimport set Reference to bz45212.
bzimport created this task.Via LegacyFeb 20 2013, 11:11 PM
Reedy added a comment.Via ConduitFeb 20 2013, 11:13 PM

In the thumbnails of those images?

Bawolff added a comment.Via ConduitFeb 21 2013, 12:03 AM

(In reply to comment #1)

In the thumbnails of those images?

And do you mean the png or the jpg thumbnail of the tiff (we support both. Jpg is the default).

Its possible that different sharpening is applied to tiffs than to jpgs (not sure off the top of my head. I would be surprised though). Its also possible that different scaling algorithms may be used for the different formats or something like that.

bzimport added a comment.Via ConduitMar 9 2014, 5:17 AM

mcdevitd wrote:

*** Bug 18014 has been marked as a duplicate of this bug. ***

bzimport added a comment.Via ConduitMar 9 2014, 5:18 AM

mcdevitd wrote:

This is also true of .jpg thumbnails of PNG uploads, I assume for the same reason (see duplicate bug report).

Bawolff added a comment.Via ConduitMar 9 2014, 7:10 AM

(In reply to Dominic from comment #5)

This is also true of .jpg thumbnails of PNG uploads, I assume for the same
reason (see duplicate bug report).

We dont do jpg thumbs of png files (png files get png thumbs), but yes, pngs are not sharpened. Only jpgs get sharpened.

I believe comment 2 is incorrect...

bzimport added a comment.Via ConduitMar 9 2014, 9:54 PM

mcdevitd wrote:

(In reply to Bawolff (Brian Wolff) from comment #6)

(In reply to Dominic from comment #5)
> This is also true of .jpg thumbnails of PNG uploads, I assume for the same
> reason (see duplicate bug report).

We dont do jpg thumbs of png files (png files get png thumbs), but yes, pngs
are not sharpened. Only jpgs get sharpened.

Yeah, I misspoke. I should have said JPG versions of PNGs.

Multichill added a comment.Via ConduitJun 7 2014, 4:21 PM

The current tiff thumbnails are of such poor quality that Commons users are uploading duplicate jpegs. This is a lot of extra work and puts and extra strain on the Commons community because everything needs to be done twice. Raising the priority of this bug.

Bawolff added a comment.Via ConduitJun 7 2014, 4:24 PM

I would like to fix this bug at the same time as bug 52045, since we're be changing the rendering config with that bug, so might as well do it all at once.

Gilles added a project: Multimedia.Via WebNov 24 2014, 3:21 PM

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