While waiting for a reply...........

I found out the reason for the image color degrade.

It's the image-re-size being completed by PIWIGO.

When I change the medium file display size ( default ) to a larger file size, the colors and saturation return to normal.

So, for the site admin, and whoever controls PIWIGO etc, during the file re-size on the gallery, its degrading the image quality.


My server settings are below.  Someone mentioned that my GL or Imagemagick is an older version, however this shouldn't be causing the image problem.



Environment
Operating system: Linux
PHP: 5.2.17 (Show info) [2015-03-24 07:46:17]
MySQL: 5.5.42-37.1-log [2015-03-24 07:46:17]
Graphics Library: External ImageMagick 6.7.9-10

Here is a link to a screen capture, of what I am seeing on my end with the smaller re-sized images as the default setting is.


http://i.imgur.com/NlIheqF.png?1

The image to the right is the same file off my HDD in windows explorer.  You can clearly see the reduction in image color saturation and brightness.



After I changed the default medium display size, larger, closer to the LARGE version, the correct colors were returned to the displayed image.

Last edited by JTX (2015-03-24 15:00:36)

Oh Very good.  I will look at that and what lightroom is doing


I noticed in lightroom it was using PROPHOTO RGB. So that is doing it.

I will look at the different settings and find out why it's using this method.

plg wrote:

Here we go:

$ exiftool 20150324060335-11ef22b8.jpg | grep -i RGB
Color Space                     : sRGB
Color Space Data                : RGB
Profile Description             : ProPhoto RGB

ProPhoto RGB is the problem with this photo. On small sizes, Piwigo removes the metadata (including the color profile), which is why your thumbnail looks bad.

If you want to fix the problem without converting your photos to sRGB, add this to your local configuration with plugin LocalFiles Editor :

Code:

<?php
$conf['derivatives_strip_metadata_threshold'] = 0;
?>

and delete all the multiple size cache on [Administration > Tools > Maintenance].

But of course the best solution is to convert your photos to sRGB color profile, this way you are sure everybody (all web browsers on all operating systems) will see the appropriate colors.

Last edited by JTX (2015-03-24 16:38:46)