Epson SC P900 what is going on

drfihl · Monday at 7:31 PM

Hi,

I got this printer several years ago – almost for free. It originally had an issue with colored streaks when printing black and white. An Epson technician couldn’t fix it, so the former owner received a replacement, and I got this one.

Since then, I’ve only used it for black and white printing. China cartridges. The color cartridges were filled with water and window cleaner and at least one was dried out. Now I’ve refilled the printer with pigment inks because I’d like to pass it on to the local community. Unfortunately, magenta is still the problem.

Symptoms:

Nozzle check: poor, and the magenta channel actually prints as cyan. Streaks. Not magenta.
Windows 11 (see pictures 1 and 2):
- High resolution → prints well, correct magenta.
- Low resolution → bad output, cyanish tint instead of pure magenta.
- Epson Print Layout → prints as with win11 driver
Linux Mint with Gutenprint (see picture 3):
- Magenta prints as cyan.
- At higher resolutions, more cyan appears, with a faint magenta “halo” around it.
QTR (see picture 4):
- Magenta is still cyan.
- At 5700 dpi, 100% = 0 (strange behavior).

The line patterns look similar to those shown in the Epson P900 service manual I found on Scribd.

Since I never saw this printer run with its original cartridges, it may have been faulty from the start. (The original owner did get a replacement, after all.)

Despite this, I think my local community can still make use of it for posters or occasional prints. But what exactly is going on here?

Any insights are welcome.

Sincerely,
Carsten Fihl

thebestcpu · Monday at 8:35 PM

Hi Carsten, I too have an Epson P900, and the color of the tubes is the same in mine, and mine is working.
The problem lies in the regular magenta channel, whose issue remains unresolved.

I would not spend any time on the six color test patterns. Those patterns do their best to reproduce the intended colors, yet my understanding is that since the Epson P900 is a ten-ink system, it will mix different inks to achieve those six patterns. The amount used of each is unspecified, yet these do not represent individual color / ink channels. It's sending you on a wild goose chase.

Just my quick thoughts
John Wheeler

thebestcpu · Monday at 9:22 PM

Also, can you share an image of the nozzle check pattern?
John Wheeler

drfihl · Tuesday at 2:10 PM

thebestcpu said:
Also, can you share an image of the nozzle check pattern?
John Wheeler

drfihl · Tuesday at 2:15 PM

thebestcpu said:
Hi Carsten, I too have an Epson P900, and the color of the tubes is the same in mine, and mine is working.
The problem lies in the regular magenta channel, whose issue remains unresolved.

I would not spend any time on the six color test patterns. Those patterns do their best to reproduce the intended colors, yet my understanding is that since the Epson P900 is a ten-ink system, it will mix different inks to achieve those six patterns. The amount used of each is unspecified, yet these do not represent individual color / ink channels. It's sending you on a wild goose chase.

Just my quick thoughts
John Wheeler

I agree (partly) with you on the 6 color test. But wonder about the difference between low and high resolution. And what happens when i go Linux and Gutenprint.

I have used QTR to flush channels in the past. Its the best option. The second best is individual purge file.

x64 · Tuesday at 3:03 PM

Looking at your nozzle check you definitely have a hardware problem. Yellow has some issues, no vivid magenta coming through, and instead some cyan leaks through the vivid magenta channel.

The nozzle check is pretty 'raw', done by the firmware. So before investigating software, the nozzle check should be near perfect. This check is also revealing why you are getting different results across different settings/operating systems: some are composing the 6 color print with the VM channel while others are not.

My recommendation is to first identify why the VM channel is leaking cyan. Then investigate the missing VM throughput (probably related). Finally address the yellow channel.

thebestcpu · Tuesday at 4:42 PM

I agree with x64 about focusing on the nozzle check issues and clearing those up first both the VM and Y ink channels.

I'm not sure about being able to discern the cyan leakage from the image, given its off-color, and it is a JPEG image, which can significantly alter fine colors due to its compression algorithm.

The oddities in all the other images, no doubt, could eventually be explained; yet, they are distractions from the obvious root cause issues revealed by the nozzle check.

John Wheeler

drfihl · 2025-09-24T08:40:31+0100

x64 said:
Looking at your nozzle check you definitely have a hardware problem. Yellow has some issues, no vivid magenta coming through, and instead some cyan leaks through the vivid magenta channel.

The nozzle check is pretty 'raw', done by the firmware. So before investigating software, the nozzle check should be near perfect. This check is also revealing why you are getting different results across different settings/operating systems: some are composing the 6 color print with the VM channel while others are not.

My recommendation is to first identify why the VM channel is leaking cyan. Then investigate the missing VM throughput (probably related). Finally address the yellow channel.

Is it still patience and TLC. Cleaning with a lint free cotton as described by Arthur Entlich? I have his manual.

Still I am very confused with the QTR. The Magenta channel, spewing Cyan, suddenly increases at 20%. I wonder if that was the initial problem that caused Epson to replace the printer with another printer to former owner. As I remenber there were cyan streaks in her B&W pictures.

Rigt now I am depleting the Magenta and the yellow by printing solely magenta/yellow with QTR. It seems to deplete the Cyan.

If nothing works I have at great B&W printer working on several channels.

x64 · 2025-09-24T14:52:44+0100

It is pointless and wasteful to continue diagnosing with software printing long as your FIRMWARE printing has obvious problems. The prints you get from QTR are meaningless for diagnostic. It is like you are trying to diagnose an car engine problem by looking at how the wheels are spinning, while ignoring the report a technician just gave you (the nozzle check)! You need to either get in there and solve the hardware problem or find someone experienced that can do that for you. Printing anything until the nozzle check is OK is pointless.

thebestcpu · 2025-09-24T15:18:00+0100

I agree with @x64. You are seeing software issues with Quad Tone RIP and it is distracting you.

To help you understand, here are the Windows reelease notes for QuadToneRIO version 2.8.2 (most recent I believe).
Note that it mentions not supporting all ten inks of the P900, simulating black, and that the VM is not supported. I think that is a pretty good indication that you cannot depend on QuadToneRIP to do what you think it is doing:

QuadToneRIP version 2.8.2 and 2.8.2 Release Notes

This is a bug fix for version 2.8.1 or 2.8.1.1 -- all users with either should upgrade.

The release also includes new versions of Print-Tool and Data-Tool

!! --- Windows Caveat --- PC users must read !!

The PC front end QTRgui unfortunately cannot support 10 inks. So due to the

importance of MK ink I've decided to simulate the switching of blank inks as has

been done for many previous Epson printers. The violet ink is not supported with this.

To accomplish this I've created to additional printers named P708 and P908 that

are usable as 8 ink printers. They will use the Black Ink selection in printing to

give you matte of photo ink. So inks are: K, C, M, Y, LC, LM, LK, LLK

Note that K represents either Photo or Matte black ink depending on the printing dialog,

just like it's always been before.

Important:

This has several side effects that one needs to be aware of. The .quad and .qidf files

are mostly the same but incompatible for using matte black ink.

This is the general idea:

Use QuadP700 and QuadP900 if you have 10 ink curves made somewhere else i.e. on a Mac,

Piezo, Boutwell. You can't use QTRgui on these.

Use QuadP708 and QuadP908 if you want to Create curves/profiles yourself using QTRgui.

It's all similar to what you might have done with previous printers

NOTE!: So I would not even count on it flushing the correct inks either

Epson SC P900 what is going on

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