[NTLUG:Discuss] color printing question - additional information

[Fred James]

Thank you for your thoughtful reply.  I can accept this difference in 
colors on screen and paper, one being from the additive, and the other 
from subtractive, color system.

I now have only two questions left and they are about the test page 
itself, and so not really important - I just have to assume there is 
something wrong with the test page if (a) the "red" hat prints red, and 
the red color swatch print brown, and (b) the purple swatch print red. 
These two colors print as expected from GIMP and other sources.

Thanks again for you input.


Steve Baker wrote:

> Fred James wrote:
> 
>> In an attempt to get a point of reference, I opened GIMP, produced the
>> same eight color samples, and sent the results to the printer in
>> question.  Here is the comparison.
>>      Color name    RH test page    GIMP
>>      ----------    ------------    ----
>>      Blue          dark, purplish  dark, purplish
>>      Red           reddish brown    red
>>      Yellow        yellow          yellow
>>      Purple        red             purple
>>      Brown         brown           brown
>>      Gold          orange          orange
>>      Cyan          cyan            cyan
>>      Green         green           green
>> Conclusions:
>> (1) Blues print very dark, almost purple
>> (2) There may be something wrong with RH's test page for the colors:
>>      (a) Red
>>      (b) Purple
>> (3) The other five colors seem to be pretty much OK.
> 
> 
> These are not un-typical findings.  Remember that your printer doesn't
> have Red, Green and Blue inks - they are Magenta, Yellow, Cyan and Black.
> 
> To get a good Red (remembering that your monitor has Red, Green and Blue
> phosphors), requires mixing Magenta and Yellow - but this does produce
> a muddier colour than your monitor represents.  Similarly, there is no
> true Blue - it's Cyan plus Magenta - which is certainly much darker and
> somewhat purple-ish than you might hope. I find that Green (which is
> printed as a mixture of Yellow and Cyan) is more vibrant than on the CRT.
> 
> I can't tell the extent of your problems from your description - but my
> Canon BC7004 produces similar results to those you describe...no matter
> whether I print from Ghostscript, GIMP, XV or Mozilla.
> 
> You just have to realise that there are colours you can display on a CRT
> that you can't print - and colours you can print that you can't display
> on your CRT.
> 
> Generally, I find that photographs need to have their Gamma settings
> cranked way up before I print them - to the point where everything looks
> terribly washed-out on the screen.
> 
> Getting reliable colour reproduction is a VERY deep subject - even getting
> colours to match from one CRT to another is difficult.
> 
>> I should still be interested in other peoples' experience with the RH
>> test page on color printers.
> 
> 
> I don't have RedHat - but I see similar results to yours if I paint the
> pure colours you describe in GIMP and print them.
> 
> ----------------------------- Steve Baker -------------------------------
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