Question about nozzle test pattern

[Music Image]

Hi,
Can some one explain to me why the vertical squares or more correctly, oblongs are all in various shades of black. Which ink tank actually prints these.?

Thanks
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[d86cfv]

Do you mean the small ones on the left hand side of the nozzel print?

If so these are a mix of CMY to "make" black. If your magenta wasnt functioning the blocks (and the letter eg "C/Y/M") would be green, just using the C and Y.

Sometimes they are not a True black and print slightly greeny or bluey, this is more evident sometimes with using compats/refills that arent a 100% match to the origionals. With genuine ones in it tends to be a pretty close match to black.

Regs,

Dan

 

[Music Image]

Thanks Dan,

yes I did mean those ones on the left, and now I understand.

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[d86cfv]

No worries, always a pleasure to share my limited knowledge lol.

Regs,

Dan

 

[digitalartist71]

Black (K) is added to CMY since even when all 3 are mixed together will result in a muddy dark brown due to impurities no matter what. Even with genuine top quality Canon Inks. To get a CMYK mixture Black (RICH BLACK), a percentage of each color is used...not necesarily 100% of all 4 colors... would be too saturated, and depended on the media, would either bleed badly, not dry, or run. When printer profiling is done, a process called INK LIMITING is used to control that. A test patch is printed using percentages of all the inks, and you choose which one held up the best to the media being profiled. That is key to get good color instead of blotchy thick runny non-drying prints.

Most desktop PC printers are RGB based printers...basically they take RGB values sent from the software program and convert them out to CMYK to the printer. Apple POSTSCRIPT (and PC) printers are CMYK printers.... so they can take CMYK values directly. I.e. In Adobe Illustrator, if you specify a object to be 100% blacK, 0% Cyan, 0% Magenta, 0% Yellow. It will print ONLY Black, nothing else. RGB printers would convert those process values to RGB values (well technically first to CIE Lab), then back out to CMYK which would be a RICH BLACK result opposed to a 100% Process blacK. Postscript printers are used for COLOR SEPERATIONS in order to create films for process printing such as screenprinting.

 

[d86cfv]

digital - i believe that when the printer is mixing the cmy to make black on the nozzel check it is not using the ink from the black cartridge, i've had situations where the black head has been totally blocked and the cmy prints out in black but the bk doesnt. Also this would be why, like i said it is a slightly off black colour, usually a dark green, or indeed i have seen it a muddy brown as you said.

Its also not possible for the bci3bk to be used on photo paper, the printer simply doesnt use it because the ink will not dry on photo paper and it will cause big issues with the other dye based inks as they all sit on the surface of the paper as you will see if you try to print a photo and dont tell it its on photo paper.

The ip3000 and 4000 are good examples of how this all works, the 3000 has BK c m & y the 4000 has bk c m y and a dye based black. When printing photo's with the 3000 all of the dark patches have a slight colour cast to them, blacks not black, even though they look perfect, if you hold them next to a print that the 4000 has done there is a big difference, the printer is actually using true black when printing.

N e hoo, slightly off tangent there - probably should go to bed as its 1:00 AM!

Regs,

Dan

 

[Music Image]

Thanks digitalartist71 for your explanation which has furthered my understanding. How interesting!!! I wondered how you could get black out of CMY.
Arnt there some very low end printers that dont even have a true black, and they just use a composite of CM&Y?

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[Music Image]

d86cfv, I didnt see your post B4 I posted so Heh, youve pipped me at the post again !!!

Thanks for your thoughts again, which are very interesting and arnt off topic.


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[d86cfv]

There is a Lexmark printer that uses a "Number 1" cartridge, this only has cmy and it prints black fine, but its fairly slow. Infact the majority of Lexmark printers will let you print with just the colour cartridge making black with cmy.
Also the HP's that take the 56 57 58, if u use just the 57 it will print black too. The old Canon BC 05's were the same, they used to print a horrible greeny colour and the text would change colour as the cartridge ran out!

 

[d86cfv]

lol, and you managed to get that one in just before my other post, darn!

Anyway, night guys!

D