Paint Shop Pro support - Color space not set for PNG files ?

Author

Color space not set for PNG files ?

Guillaume Dargaud

2006-03-14, 6:16 am

Hello all,
I'm continuing to discover how color spaces and profiles work, and found
something: if I choose to work using AdobeRGB color space, TIF and JPG files
are saved with the proper colorspace information in them. Not so with PNG
files where no info seems to be saved.

Is that a bug, a limit of the PNG format (I doubt it), or something I
overlooked ?

I don't think they are set to sRGB because I don't get the warning message
when I open them from a PSPX in AdobeRGB mode.
--
Guillaume Dargaud
http://www.gdargaud.net/Antarctica/
"I love cooking with wine. Sometimes I even put it in the food."

Fred Hiltz

2006-03-14, 6:21 pm

Guillaume Dargaud wrote:
> Hello all,
> I'm continuing to discover how color spaces and profiles
> work, and found something: if I choose to work using
> AdobeRGB color space, TIF and JPG files are saved with the
> proper colorspace information in them. Not so with PNG
> files where no info seems to be saved.
>
> Is that a bug, a limit of the PNG format (I doubt it), or
> something I overlooked ?
>
> I don't think they are set to sRGB because I don't get the
> warning message when I open them from a PSPX in AdobeRGB
> mode.

The standard provides for embedded color spaces, see
http://www.libpng.org/pub/png/spec/...-Contents.html. However,
that does not require programs to support them. To my knowledge,
none of the popular image editors does. It is not a bug. Like many
standards, PNG is so large that few, if any, applications implement
all of it.
--
Fred Hiltz, fhiltz at yahoo dot com

redwoodtwig@gmail.com

2006-03-15, 6:22 pm

How do you know your JPG files have colorspace information in them?
Are reading the EXIF or have you some method for finding out what
colorspace information is actually there?

Brandon Smith
http://brandonsmithgallery.com

Guillaume Dargaud

2006-03-15, 6:22 pm

Hello Brandon,

> How do you know your JPG files have colorspace information in them?
> Are reading the EXIF or have you some method for finding out what
> colorspace information is actually there?

Easy: in PSPX (which I just download for trial a few days ago), if you
select a colorspace in [File][Color Management][Color Working space] and you
load an image with a different embedded colorspace, it tells you so and asks
if you want to convert it. If there's no colorspace info in the file _or_ if
it's the correct one, it just loads it quietly. FYI, JPEG and TIFF embedded
colorspaces work fine.

Now about something different, I see with pleasure that PSPX supports 16
bit/channel files... partially. For instance 48/64 bits PNG are not
supported but TIFFs are. Some operations (color levels for instance) work on
16 bits images, but others do not (what, no histogram correction ?!?). Is
there a list of the supported 16 bits operations ? And the upcoming ones in
the next subversions ?
--
Guillaume Dargaud
http://www.gdargaud.net/Climbing/
"Faith can move mountains but let them happily fall down on the heads of
other people. What's the point in moving mountains when it's so simple to
climb over them ?" - Boris Vian, surrealist French writer and singer, En
verve.

David Gilbert

2006-03-15, 6:22 pm

On Wed, 15 Mar 2006 18:14:04 +0100, "Guillaume Dargaud"
<USE_MY_WEBSITE_FOR_MAIL@gdargaud.net> wrote:

>
>Now about something different, I see with pleasure that PSPX supports 16
>bit/channel files... partially. For instance 48/64 bits PNG are not
>supported but TIFFs are. Some operations (color levels for instance) work on
>16 bits images, but others do not (what, no histogram correction ?!?). Is
>there a list of the supported 16 bits operations ? And the upcoming ones in
>the next subversions ?

See:
<http://support.corel.com/scripts/ri...lwZT0zJnBfcHJvZ
F9sdmwxPTE1NSZwX3Byb2RfbHZsMj0xODAmcF9zb3J0X2J5PWRmbHQmcF9wYWdlPTE*&p_li=>
--
Regards
David: NorthWest, England