Which color inks are used to print pure black?

[oldabelincoln]

I am aware that under most circumstances, Canon 5 color (CMY+photo black+pigment black) printers will use differing amounts of colors in addition to photo black when printing black in a photo. I thought I had seen the details some years ago in a Canon Service Manual for the ip4000, but no, it's not in there. And I need that info to figure out what seems to be a clogged nozzle problem.

Here's my problem.

My wife's iX6520 (225/226 inks) was in the shop with a paper jam. So she printed a flower photo with a very dark background on my MX892 (also 225/226 inks), and it came out odd looking in 2 areas of the dark background. Using the original JPG file and Paint Shop Pro's eyedropper to get color values, I determined that the dark parts that printed OK were NOT pure black in the original, but were slightly off-black in the random ways one would expect in a photo. The two fairly well defined parts of the dark background that were pure black in the original did not print OK, and these two parts printed as a rich medium purple! And I do mean purple, not magenta. If it had been magenta, I'd be looking for the green nozzle to be clogged, except there is no green ink on a 5 color Canon, and anyway, it's purple at issue, not magenta. The result was easily duplicated, so it was not a one-time glitch. And I used different programs to initiate the print, so it wasn't program-dependent. Definitely an issue with the printing process, and not the file or the program used to print the file, or the monitor (the original looks the same on two different monitors).

The inks are from Precision Color, refilled into in their carts. The paper was Costco Glossy printed as Canon Photo Pro Platinum, my wife's usual setting for that paper. Print Quality was set to High.

I'm used to weird colors from clogged nozzles, but this was a new one. What the devil is the complement of purple?

To see what was going on, I printed with unchanged settings using plain paper and got an identical result - not some sort of issue with the paper itself, then. Eventually with different settings, I found that if I used anything (or at least the decent subset of anything that I tried) other than a Photo Pro Platinum paper setting, the problem went away. That told me that the particular way that the printer prints pure black on Photo Paper Platinum setting has something to do with it, and presumably that is the mix of inks used to make pure black under the circumstances.

Just to tie this all up, my wife's iX6520 is now back from the shop, working OK, and using the settings that started all this, produced a perfect print, underlining that my MX892 is the issue, presumably a clogged nozzle(s?).

Does anyone have either a solid idea about how purple came about, or at least the details of which inks were most likely used to print pure black under the circumstances?

 

[PeterBJ]

Could you upload a scan of the misprinted flower photo? A crop clearly showing the misprint and a part that prints OK is sufficient. Could you also upload a nozzle check from the failing printer?

Photo (dye) black isn't truly black but a very dark purple, so some cyan and maybe also yellow is added to compensate for this. My guess is that the printer has a problem with cyan and possible also yellow.

To see the complementary colour of the purple you could use an image handling program to invert the scan of the flower photo. The purple areas will now be the complementary colour, and so show what is missing.

 

[The Hat]

OK the first thing I have to say is STOP printing your documents/Photos immediately and don’t print any more till you can resolve this issue.

Yes you have a problem but you’re going about it all the wrong way and getting your printer into bigger problems, like permanently damaging your print head.

Let’s deal with your clog issue first if it is at clog at all, what you need to do is to print a nozzle check which looks like this.

By examining this printout you will see clearly which colour is failing to print, now run a deep head clean (One only) and then print another nozzle check.

Then compare both of these nozzle prints and see if there is any differences in them (Improvements of missing segments). (Your missing Yellow)

If not you will need to replace the cartridge of that missing colour with a new one and then run a normal head clean followed by another nozzle check.

You should now have all the colour working normally again but if you don’t you may have other issues, like a difficult ink clog or worse a damaged print head, you should post all 3 nozzle prints on here to get a better diagnosis.

To print a black photo, your printer will use Cyan Magenta and Yellow to achieve this and will use the photo black sparingly as a highlighter but it won’t use the pigment black at all.

The only time pigment black is used is to print plain text documents like Word, it is reserved for that single purpose but you can however print a single B&W photo on plain paper using this pigment black..

 

[martin0reg]

Grey and black is mixed from all colors (mostly from C M Y, with addition of photoblack K) - if the printer is set to any higher quality than plain paper.
If set to plain paper, deep blacks are printed with "text black" (the bigger PBK cart). Because this is only for text and graphics, the black areas in a photo could come out "too black", but definitely not colored.
Post a nozzle check.
PS: the Hat was first...stop printing until the nozzle check is flawless..

 

[oldabelincoln]

All,

Thanks for the advice.

I did nozzle checks throughout the course of the testing I described, and all were perfect. Or so I thought at the time.

But I did one again just now, and finally noticed that - duh! - the photo black strip at the bottom wasn't printing anything at all. Completely blank. Most likely that was the case before, and I missed that before, multiple times, just as I almost did this time. I've been looking at Canon nozzle checks for over 10 years, so I have no excuse.

Sure enough, the LED on the photo black cartridge is blinking, although no error shows up on the LCD panel or the software, now or earlier. We checked the cartridge LEDs when we first noticed the error, and it wasn't blinking then. But we've had a lot of problems with the resetter giving a good result, no blinking cartridge after inserting the cartridge in the print head, only to end up with a blinking LED and front panel error after the printer was closed up, so likely I missed that one as well.

I'll have to get a working photo black and test, but at the moment it looks like the complement of purple is photo black.

I'll post again when all is allegedly working well and my blush has subsided.

Thanks again to all.

 

[oldabelincoln]

Putting a functioning photo black in place completely solved the problem. True black in the original prints as purple if photo black is not functioning, at least for an MX892. Interestungly, slightly off-black portions in the original printed ok with a non-functioning photo black.

Thanks to all for the reminder that it's not enough to do the basics - you have to do them with thoroughness.

 

[PeterBJ]

Thank you for the feed-back