[NTLUG:Discuss] color printing question - additional information

[Steve Baker]

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.

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