Re: [Gimp-print-devel] Gutenprint and Epson Pro 7900

[Alvaro K. <ku...@gm...>]

To print 6 colors on EPSON Stylus Pro 7890 I need to use <InkName
translate="text" name="PhotoCMYK" text="Six Color Photo" InkID="CcMmYK">

To swap the Ink Channels on 7890 we need to modify the
pro_ultrachrome_k3v.xml file.

If I want to change the Yellow Color to Light Black I would need to change:

   <channel name="standard_yellow" index="3">
    <HueCurveParam name="YellowHueCurve"/>
    <subchannel color="4" name="Yellow" text="Yellow" translate="text">
     <ChannelDensityParam name="YellowDensity"/>
    </subchannel>
   </channel>

To:

   <channel name="standard_yellow" index="3">
    <HueCurveParam name="YellowHueCurve"/>
    <subchannel color="0" subchannel="1" name="Yellow" text="Yellow"
translate="text">
     <ChannelDensityParam name="YellowDensity"/>
    </subchannel>
   </channel>


The color is the low 4 bits of the hex value; the subchannel is the high 4
bits.
So LightBlack has a hex value of 0x10 and Yellow has a hex value of 0x28.

Well, That is in theory. I have searched this mailing list for all the bits
I could find about this.

Is this right? I am missing something?

I could not test it yet because I do not have all the inks on the printer,
I am waiting for them to be delivered.

Meanwhile I am learning as much as I can from Gutenprint. I am trying to
gather information as much as I can.

When I finish this I will try to write a tutorial of sorts because this
topic seems to surface from time to time in the mailing list.

Thanks for your patience and good work!

On Mon, Feb 15, 2021 at 5:24 AM Alvaro Kuolas <ku...@gm...> wrote:

> I have a 7890 (same as 7900 but with 8 colors instead of 10: no Orange, no
> Green channels).
>
> I have a busted Yellow Channel, and possibly the LLK as well.
>
> It is possible to make it print in 6 colors? Like CcMmYK ?
>
> I could reorder the channels as described in this thread, but, How to make
> it behave like a 6 color printer?
>
> Thanks!
>