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#1 2017-05-17 02:52:41

todd
Member
Registered: 2014-11-27
Posts: 21

100% image quality instead of 98%

hello,

I'd like to have 100% image quality but in the photo size settings, it caps it at 98%. How do I change this?

Thanks,
Todd

Piwigo version: 2.9.0

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#2 2017-05-18 23:25:48

Knitter
Member
Location: Denmark
Registered: 2016-05-26
Posts: 58
Website

Re: 100% image quality instead of 98%

Also what I want. I edit my photos the way I want them, so I don't need another program to tamper with them.

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#3 2017-05-19 10:15:06

plg
Piwigo Team
Location: Nantes, France, Europe
Registered: 2002-04-05
Posts: 13072
Website

Re: 100% image quality instead of 98%

JPEG 100% doesn't really make sense. Let's take an example. I have taken an original photo, 3.7MB, 2592x3888 pixels from my Canon 40D (yes, it's starting to be quite old...). I put it this photo in Piwigo and set the quality to 95, then 98 then to 100 (directly in the database because Piwigo admin screen forbids it).

Code:

[pierrick@pierrick-desktop] /tmp/jpeg-quality
$ ll -h
total 4.5M
-rw-r--r-- 1 pierrick pierrick 3.7M 2017-05-19 09:56 sample-original.jpg
-rw-r--r-- 1 pierrick pierrick 170K 2017-05-19 10:00 sample-large-jpeg95.jpg
-rw-r--r-- 1 pierrick pierrick 239K 2017-05-19 10:01 sample-large-jpeg98.jpg
-rw-r--r-- 1 pierrick pierrick 354K 2017-05-19 10:05 sample-large-jpeg100.jpg

The "large" size is 504x756 pixels. As you can see, quality 95% is 170KB while quality 100% is 354KB. Exactly twice as heavy. Now, let's compare the resulting quality, visually speaking.

I don't tell you which photo is 100 or 98 or 95 per cent. You guess, before looking at the file name. Good luck ;-) As you might imagine I look at many photos, for my work, and I can't see any difference with my eyes.

http://piwigo.org/forum/showimage.php?pid=167533&filename=sample-large-jpeg95.jpg
http://piwigo.org/forum/showimage.php?pid=167533&filename=sample-large-jpeg100.jpg
http://piwigo.org/forum/showimage.php?pid=167533&filename=sample-large-jpeg98.jpg


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#4 2017-05-19 11:24:13

Knitter
Member
Location: Denmark
Registered: 2016-05-26
Posts: 58
Website

Re: 100% image quality instead of 98%

I use Photoshop CS6 to edit my photos, and I reduce the quality to level 7 (middle) and I don't want them  further reduced. Which level should I use to compensate for this further reduction?

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#5 2017-05-19 18:33:36

todd
Member
Registered: 2014-11-27
Posts: 21

Re: 100% image quality instead of 98%

I most often resize my photos to 1280px wide or 1156px wide at 90% quality before uploading to Piwigo, and have sharpened how I want and don't want any further changes.

Occasionally I resize to 1500px or 2000px wide to enable zooming into details, but even then I've already sharpened and reduced the output quality and don't think I need the forced extra management, as it does seem to change the appearance from the processing I applied before upload, usually dulling the sharpened look a little bit.

Granted 2% is minor, but I'd still like to be able to turn it off (to 100%) and compare things for myself.

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#6 2017-05-23 09:01:55

cache
Member
Registered: 2017-05-20
Posts: 11

Re: 100% image quality instead of 98%

Same question, where to disable this setting?!

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