Corel draw color conversion strange behavour
Sakis
After importing the bitmap (scanned via twain or imported as .TIF) i must
convert it to CMYK to use it.
First i copied bitmap to make a simple test.
First copy converted using CorelDraw Bitmaps/Mode/CMYK color (32bit)
command. On second copy i double clicked it to edit it in Photopaint the
same way (.../Mode/CMYK).
Can you tell me why the results where totally different although i use
exactly the same color management and the conversion applied the same
profile ?
Clemens M. Hürten
"Sakis" <s...@in.gr> schrieb im Newsbeitrag news:3bdd08df_1@cnews...
Hello Sakis,
I think I can help you, but you should post all the settings which you
did in colormanagement, the OS and wether you have Windows ICM in use
when printing and what is your output device (printer).
--
Have a nice and successfull day!
Clemens M. Hürten
IdeeCreativ (www.ideecreativ.de)
Advertizing & Marketing
Stuttgart / Germany
Sakis
well these are my CD color magement settings
Corel's internal sRGB
Generic euro positive proofing for separations
My own monitor (SONY F520) installed profile (2.2/6500)
Epson 1290 own monitor for soft proofs
No further color management for i/o or scanner
From internal RGB arrow right to CMYK separations printer. From there arrows
to monitor and inkjet printer.
Kodak engine and automatic rendering intent
That's all Clemens. I've saved those settings under a name and Photo paint
uses the same color management setting.
Whenever i convert an imported or created RGB bitmap directly in CD the
result is totaly different as of its color than the same bitmap edited and
converted in PP and returned to CD page.
I use the same command (Bitmaps/Mode/CMYK) in both programs and i don't
export the bitmap from CD to PP and vice versa. I just double click it in CD
to directly call PP.
Thanks again
Sakis
"Clemens M. Hürten" <clemens...@t-online.de> wrote in message
news:9rk4vo$4kp$04$1...@news.t-online.com...
Clemens M. Hürten
I will respond within the quotes...
"Sakis" <s...@in.gr> schrieb im Newsbeitrag news:3bdf9a29_3@cnews...
> Thank you Clemens for your reply,
>
> well these are my CD color magement settings
> Corel's internal sRGB
> Generic euro positive proofing for separations
> My own monitor (SONY F520) installed profile (2.2/6500)
> Epson 1290 own monitor for soft proofs
What does this mean "own monitor for soft proofs"? Do you run Windows
2000 or Win 98 and use Windows ICM Colormatching? Did you have activated
the Epson ICC-profile in
Start/printers/Epson1290/device-properties/colormanagement/...profile ?
In this case Corel cannot simulate the CMYK-Output of your separations
printer on the Epson because it does not know the values of the Epson
gamut.
You should erase the profile from the Windows / printer settings and
then use the profile for the Epson only in the Corel Colormanagement.
(But perhaps this has not been the main point of your problem.)
> No further color management for i/o or scanner
So I suppose you are operating some kind of office scanner which will
output in sRGB format by default. In this case you should check, which
sRGB is outputted from the scanner. There are different sRGB profiles
with different profiles. The Corel "internal sRGB" is not identical to
that sRGB which comes on Win 98 or Win2000. I recommend the use of the
Microsoft profile, if you want to stay in the "sRGB office
world"-workflow.
> From internal RGB arrow right to CMYK separations printer. From there
arrows to monitor and inkjet printer.
These settings will give you a monitor simulation of the output of your
CMYK separation device and the Epson-printer should also simulate the
colors of your CMYK-device (if you have told Corel, which profile the
Epson should use and if you don't profile your Epson once again at
printer / Colormanagement settings / ....
> Kodak engine and automatic rendering intent
Automatic rendering intend may result in differences when you take a
certain color out of a picture in your layout and then design any grafic
with this same color, especially if you set the grafic color to CMYK (as
it is common practice)
> That's all Clemens. I've saved those settings under a name and Photo
> paint uses the same color management setting.
> Whenever i convert an imported or created RGB bitmap directly in CD
the
What conversion do you mean? Do you convert from RGB to CMYK? If this is
true, Corel will allways applicate the profile you have defined for your
CMYK-device (and never that which is defined for your
composite-printer!)
But why do you convert the bitmaps to CMYK? This will be done
automatically if you generate a EPS or PS or PDF file with the
appropriate settings.
> result is totaly different as of its color than the same bitmap edited
> and converted in PP and returned to CD page.
*Where* is this difference? On the monitor or when printed on your Epson
or CMYK device?
Lets assume, the differences will be shown on the monitor. Let's say it
clear: If you convert the same RGB bitmap to CMYK one time in CorelDraw
and the other time in PP then you would see very different colors,
inspite the colormanagement settings are identical?
That's strange indeed!
I have just tried exactly the same I supposed above (hoping that I have
understood you right). My results: Works nice here! Absolutely identical
results! The differences between RGB and CMYK in CorelDraw conversion
and that of the same conversion in PP were very subtel in the dark areas
of the bitmap. That is easy to understand, because in good CMYK-profiles
there is integrated a black generation information which is necessary
for nearly all printing machines / presses in order to limit the maximum
ink amount and to reduce colors in favor to black.
Then I imported the conveted CMYK bitmap from PP to Draw. No problem
else! There was absolutely no difference between the CMYK bitmap which
was converted in Draw and that which I imported after conversion from
PP.
> I use the same command (Bitmaps/Mode/CMYK) in both programs and i
don't
> export the bitmap from CD to PP and vice versa. I just double click it
in
> CD to directly call PP.
If you do the conversion, there is a dialog´with a control box in it. If
activated it says: For this conversion the Profile.... will be used.
Make sure that you have activated this control box!!!
If you don't, Corel will convert but nobody will be able to tell you
what sort of conversion is performed! :-))
Clemens M. Hürten
I spent my time to help you. Would you please be so kind to spend your
time to give me (and the others in the newsgroup) feedback wether my
proposals did work for you?
This newsgroup does not only live from the tips and hints, people are
giving but also from the feedback, wether the tip worked or not.
Have a nice and successfull day!
Clemens M. Hürten
IdeeCreativ (www.ideecreativ.de)
Advertizing & Marketing
Stuttgart / Germany
----- Original Message -----
From: "Clemens M. Hürten" <clemens...@t-online.de>
Newsgroups: corel.graphic_apps.draw10
Sent: Wednesday, October 31, 2001 5:01 PM
Subject: Re: Corel draw color conversion strange behavour
> Hello Sakis,
> I will respond within the quotes...
>
> "Sakis" <s...@in.gr> schrieb im Newsbeitrag news:3bdf9a29_3@cnews...
> > Thank you Clemens for your reply,
> >
> > well these are my CD color magement settings
> > Corel's internal sRGB
> > Generic euro positive proofing for separations
> > My own monitor (SONY F520) installed profile (2.2/6500)
> > Epson 1290 own monitor for soft proofs
>
> What does this mean "own monitor for soft proofs"? Do you run Windows
> 2000 or Win 98 and use Windows ICM Colormatching? Did you have
activated
----------------------------snipp
Sakis
I'm sorry for my delayed reply but i didn't used net the last days
I read very carefully what you told me. Unfortunately everything here seems
ok as i have CM configured the way you told me but the problem still exists.
Imaging that i have in CorelDraw a scanned 24bit rgb bitmap that i simply
want to convert to cmyk. Just for simplicity assume that i have all color
management options disabled except CMYK (Euroscale) and monitor (my own
monitor icc profile installed in Windows XP).
My first try is to use CorelDraw Bitmaps/Mode/CMYK color (32bit). In the
next dialog i apply icc profile (cmyk)
On a second copy of the original 24bit rgb bitmap i double clicked it to
edit it in Photopaint. In PP i use exactly the same Mode/CMYK menu commands
to convert it in 32bit cmyk. Again i order to apply icc profile using the
same CM options as in CD. When i close PP after convertion and go back to
CorelDraw the last converted bitmap color is somewhat different than the
previously converted (just in CD)
That's my problem.
Thanks for your help and sorry again for my delayed reply
Sakis
"Clemens M. Hürten" <clemens...@t-online.de> wrote in message
news:9s0il0$ksp$07$1...@news.t-online.com...
Clemens M. Hürten
"Sakis" <s...@in.gr> schrieb im Newsbeitrag news:3be688d4$1_2@cnews...
> Hello Clemens,
>
> I'm sorry for my delayed reply but i didn't used net the last days
> I read very carefully what you told me.
OK, no problem!
> Unfortunately everything here seems
> ok as i have CM configured the way you told me but the problem still
exists.
> Imaging that i have in CorelDraw a scanned 24bit rgb bitmap that i
simply
> want to convert to cmyk.
> Just for simplicity assume that i have all color
> management options disabled except CMYK (Euroscale) and monitor (my
own
> monitor icc profile installed in Windows XP).
Just for simplicity...? The internal workspace will always remain RGB
data. And if you open a CMYK bitmap, it will automatically converted by
the internal color-engine (which you can choose between Kodak or Windows
ICM). Even if you will switch off any colormanagement in Corel, there
has to happen a conversion from CMYK to RGB because ther is no monitor
on earth which is able to show you colors by CMYK!
At the max you could prohibit the use of any profiles within the
colormanagement!
> My first try is to use CorelDraw Bitmaps/Mode/CMYK color (32bit). In
the
> next dialog i apply icc profile (cmyk)
Yes, exactly what I did here also.
> On a second copy of the original 24bit rgb bitmap i double clicked it
to
> edit it in Photopaint.
That's a difference but I think it should not make the point. When I
tried this, I had a RGB bitmap on my harddisk. The one time I imported
it in Draw and changed it to CMYK there. The other time I opened it in
PP and converted it there. I did _not_ open it from within Draw to edit
it.
But still I think, that should not make any difference! Perhaps you try
it again my way?
> In PP i use exactly the same Mode/CMYK menu commands
> to convert it in 32bit cmyk. Again i order to apply icc profile using
the
> same CM options as in CD. When i close PP after convertion and go back
to
> CorelDraw the last converted bitmap color is somewhat different than
the
> previously converted (just in CD)
> That's my problem.
The main difference is, that any bitmap which is imported to Draw, will
be changed to a Corel proprietary format within the layout. If you are
going to edit it in PP it may be that it is converted again and when
closing PP it will come back to Draw again. Might be that this is the
cause for deviations. But I never have seen deviations before.
I generally work with CD 9 instead of the weak CD10. For you I tried all
the things in CD10. In CD9 I never have seen differences.
>
> Thanks for your help and sorry again for my delayed reply
>
> Sakis
>
---------snippp
Sorry but I think I cannot give you more help. But we are interested
here, wether you will still find differences, when you proceed the way I
did.
--
Valdas Vilutis
This happens, because is bug in Draw color engine. Guilt is rendering
indents in color management. By default, in rendering indents Draw uses
Automatic mode from old old times. Automatic mode means, that for vector
objects must be active by default saturation rendering indent, for
bitmap objects - perceptual. But due bug in color engine for all objects
Draw in Automatic mode uses saturation rendering indent. Paint by
default uses proper perceptual rendering indent.
If you change in Draw color engine rendering indent from Automatic to
Perceptual, you must get same result with bitmaps directly in Draw as in
Paint. But this means, that for vector objects perceptual will be active
too, what in some rare cases may do problems...
Valdas Vilutis
Vilnius, Lithuania
Valdas Vilutis
"Clemens M. Hürten" wrote:
> Just for simplicity...? The internal workspace will always remain RGB
> data. And if you open a CMYK bitmap, it will automatically converted by
> the internal color-engine (which you can choose between Kodak or Windows
> ICM). Even if you will switch off any colormanagement in Corel, there
> has to happen a conversion from CMYK to RGB because ther is no monitor
> on earth which is able to show you colors by CMYK!
> At the max you could prohibit the use of any profiles within the
> colormanagement!
Under my knowledge internal RGB color space is active only for RGB mode
and maybe few others modes. CMYK mode don't have any common with Draw
RGB internal color space and here is no internal conversions from CMYK
to RGB at all. But maybe I am mistaken. Where yuo get your data about
it? I'm not shure, but seems, that even PhotoShop 6 in CMYK mode uses
special CMYK internal spaces...
In monitor case here is no direct CMYK-RGB conversion too. Draw
(exactly, Kodak or Windows ICM engine) converts at first from CMYK to
independent LAB and after this from LAB to monitor RGB color space.
Valdas Vilutis
Vilnius, Lithuania
Sakis
issue.
I think that Valdas is right. After switching from automatic to perceptual
CoreDraw converts RGB bitmaps to CMYK tha same way as PP. I think that's OK
although it's still another CD bug.
Thanks again folks
Sakis
"Valdas Vilutis" <val...@itpa.lt> wrote in message
news:3BE72216...@itpa.lt...
Clemens M. Hürten
"Sakis" <s...@in.gr> schrieb im Newsbeitrag news:3be79575_3@cnews...
> Thank you both for your help. You helped me a lot to bypass the
described
> issue.
> I think that Valdas is right. After switching from automatic to
perceptual
> CoreDraw converts RGB bitmaps to CMYK tha same way as PP. I think
that's OK
> although it's still another CD bug.
>
> Thanks again folks
>
> Sakis
>
Hello Sakis,
do you remember my posting from 31th October? There i wrote:
> Automatic rendering intend may result in differences when you take a
> certain color out of a picture in your layout and then design any
grafic
> with this same color, especially if you set the grafic color to CMYK
(as
> it is common practice)
I think you did not try out to change the rendering intent?
Further:
It is NO bug in Corel color engine! If you set rendering intent to
automatic, and you will get no good results by that, how can you accuse
Corel? It was you who made this setting.
And a word to Valdas:
I have checked all these workflow about two years ago and did read many
literature about this. Thats the reason, why I can say that Corel's
color engine can only work with RGB workflow, becaus eit is by design.
If you want to look at it in sophisticated manner, then I can tell you
that every color calculation which comes from internal RGB is calculated
via Lab and Lab is like a bridge in this process.
You can open any input / output and monitor profile and you will allways
find, that they translate from CMYK to Lab or RGB to Lab but never
directly from CMYK to RGB or vice versa. And then there are profiles
which are internally defined as "spac" type. These are color space
definition profiles which describe a workspace like sRGB or ECI-RGB.
As I did not want to write "books" here in my postings, I simplified my
posting and did not mention the Lab conversion step in between, because
I want, that people can understand me.
--