XnView Software

The Greyscale B&W pictures (8 bits) read by XnView are darker than those read by PhotoShop.
I tried to know why. My diagnosis is the following : XnView does'nt read properly Greyscale pictures.
Indeed, if I compare un greyscale chart read by PS and by XnView, I notice the following results :
read by PS / read by XnView
0 / 0
10 / 6
20 / 10
30 / 14
40 / 20
50 / 26
... / ...
100 / 65
... / ...
240 / 233
250 / 248
255 / 255

That explains the darkening !
The problem is the same with TIF or JPEG format

I located only one post about a similar problem but without solution to fix : http://newsgroup.xnview.com/viewtopic.php?f=36&t=25212

I'm using the last version (1.99.5) but the problem existed with the previous versions

Thanks a lot for your help

I forgot to mention that XnView is running under Windows XP SP3
Sorry

PhotoShop would sometimes apply color profiles...

You should try opening your images in other programs, to be sure.

I've continued to investigate towards PS (thank to MaxSt for the idea!) and I noticed that the problem is only for the greyscale pictures resulted from a RGB to greyscale conversion done with PS. If the picture is originally a greyscale picture, PS and XnView read the picture in the same way!
Therefore, XNVIEW IS NOT RESPONSIBLE.
It's bother for me because I scan a lot of B&W negatives in RGB format and I convert in greyscale format with PS
(the conversion made by scanner is not satisfactory)
That means all my greyscale pictures converted with PS are not usable with other viewers.

Now, I must understand why PS applies such a profile when it converts, profile compensated when it reads the file.

Sorry to have you disturbed useless!

For those interested :
To avoid the above mentionned problem, you must modify the PS gray workspace : from "dot grain 15%" (default value) to "gray gamma 2.2"

floyer wrote:For those interested :
To avoid the above mentionned problem, you must modify the PS gray workspace : from "dot grain 15%" (default value) to "gray gamma 2.2"

Thank you for reporting back, floyer (-:

FYI: Batch processing these samples…

• ew0031477633c-straightup-320-srgb.png
• ew0031477633c-black00.png
• ew0031477633c-black00-srgb1.png
• ew0031477633c-black07.png
• ew0031477633c-black07-srgb1.png

… with PngOptimizer gets rid of ICC profiles as well as gAMA chunks.

(Source files and output were inspected using TweakPNG.)