Why are light cyan and light magenta used in a 6 ink system?

[Ink stained Fingers]

You are listing a Canon G5070 with your personal data, is this still correct ? This Megatank printer uses 4 inks - black pigment and CMY dye inks, it might be difficult to extract the inks from the tanks to swap them, it is pretty important that no air gets into the tubing. You may need to wait with the ink swapping until the colors run empty. A CIS printer in my understanding is a cartridge type printer with a CISS retrofit by the user, after installation. There are as well quite some larger printers with cartridges which don't move but feed the ink via tubes as well , models which I wouldn't call a CIS printer - sorry for the misundertanding that you use a Megatank printer and call it a CIS printer.
Printers with this 4- ink configuration have a limitation - with the black ink, the pigment ink is only used for the normal and matte/inkjet paper setting, and not for photo printing on glossy paper, the black parts of an image are mixed with the CMY inks which is not really black but pretty dark with a color cast - mostly violet. And it could be that the pigment ink is not used as well on normal or matte paper if boderless printing is activated - I don't know if that's available on this Megatank printer model, and the pigment black is not used by Canon printers if full duplex is available and selected. Could this black issue be one of your print quality concerns ?
There is a work around on Epson 4-color printers that you use a dye black ink instead and just print with the matte paper setting on glossy paper to activate the use of the black ink channel. Epson does not block that when printing borderless.

 

[aCuria]

You are listing a Canon G5070 with your personal data, is this still correct ? This Megatank printer uses 4 inks - black pigment and CMY dye inks, it might be difficult to extract the inks from the tanks to swap them, it is pretty important that no air gets into the tubing. You may need to wait with the ink swapping until the colors run empty. A CIS printer in my understanding is a cartridge type printer with a CISS retrofit by the user, after installation. There are as well quite some larger printers with cartridges which don't move but feed the ink via tubes as well , models which I wouldn't call a CIS printer - sorry for the misundertanding that you use a Megatank printer and call it a CIS printer.
Printers with this 4- ink configuration have a limitation - with the black ink, the pigment ink is only used for the normal and matte/inkjet paper setting, and not for photo printing on glossy paper, the black parts of an image are mixed with the CMY inks which is not really black but pretty dark with a color cast - mostly violet. And it could be that the pigment ink is not used as well on normal or matte paper if boderless printing is activated - I don't know if that's available on this Megatank printer model, and the pigment black is not used by Canon printers if full duplex is available and selected. Could this black issue be one of your print quality concerns ?
There is a work around on Epson 4-color printers that you use a dye black ink instead and just print with the matte paper setting on glossy paper to activate the use of the black ink channel. Epson does not block that when printing borderless.

The “blackness” of text on regular office A4 copier paper is significantly less “black” compared to a print from one of my laser printers on the same paper. It is more of a grey shade rather than black to my eyes.

A fresh print on Canon photo paper does yield darker blacks in the photo as compared to the text in copier paper, so I suspect either the pigment black is or poor quality or the copier paper has something to do with it… but it doesn’t make a whole lot of sense to me to spend extra on paper for documents

The text looks the same regardless if duplex is active or not, so i think the pigment black is used for text in both cases. We do print duplex whenever possible, and the black ink levels diminishes far faster than the color so I am pretty confident the text is printed using pigment black ink

The fact that pigment ink is not used for photo printing is new to me.

Given that the photo prints on canon paper are visibly fading while the pigment black text prints on regular paper are not, it does make sense that the pigment black is not used for photo printing. Otherwise the black parts of images should not fade.

However it now sounds fairly pointless to fill the G5070 printer with G570 inks given the limitations with black ink. G570 inks will also make printing documents more expensive

Borderless printing IS available on the G5070, I have successfully printed A4 and 4R images borderless.

 

[Werwolf1985]

Epson does not block that when printing borderless.

Tried this with an ET 15000. I was wondering why printing borderless was giving me wrong colours on matte paper when using ICC profiles that were prepared before printing not borderless. And black was only a mix of CMY when printing borderless. Thought, it was a printer error... So using a black dye ink instead of a pigment ink and printing on glossy papers with matte setting and borderless would not work for me on this Epson

 

[pharmacist]

Actually the best colour configuration with optimal gamut, good gloss and minimal amount of colour inks would an 8 colour print head (likewise used in R3000/Epson Pro 38800/P800):
matte black, photo black, vivid magenta, cyan, yellow, gray, chromatic red and gloss optimizer
combined with the variable droplet technology you will have good compromise between optimal ink colours (both matte and photo black loaded, gloss optimizer for superior gloss, gray for neutral ABW prints and chromatic red for better skin tones, deeper reds, oranges and even blues and purples) and using only 8 ink channels. No light colours needed.

 

[Ink stained Fingers]

The fact that pigment ink is not used for photo printing is new to me.

Pigment blacks come in 2 versions - a photo black which printers uses on glossy papers, and a black ink for matte papers - inkjet papers - normal copy papers. The 4-ink printers typically use CMY dye inks and a matte black for the print on copy paper depending on the paper type selection in the driver. But this may vary with additional driver settings - like borderless or duplex or the quality setting, and this varies between Epson and Canon. The Epson printhead can generate diffferent droplet sizes for different quality settings - Canon printers only print one droplet size per nozzle row , a pretty large size since there is only one nozzle row for black. And there are mulitple nozzle rows for C and M with different smaller droplet sizes.
Thanks for the input about the ET-15000 behaviour.

The GI-53 inks of the G550 printer would fix the fading problem , this issue is separate from the black ink issue.

 

[James Mike]

Pigment blacks come in 2 versions - a photo black which printers uses on glossy papers, and a black ink for matte papers - inkjet papers - normal copy papers. The 4-ink printers typically use CMY dye inks and a matte black for the print on copy paper depending on the paper type selection in the driver. But this may vary with additional driver settings - like borderless or duplex or the quality setting, and this varies between Epson and Canon. The Epson printhead can generate diffferent droplet sizes for different quality settings - Canon printers only print one droplet size per nozzle row , a pretty large size since there is only one nozzle row for black. And there are mulitple nozzle rows for C and M with different smaller droplet sizes.
Thanks for the input about the ET-15000 behaviour.

The GI-53 inks of the G550 printer would fix the fading problem , this issue is separate from the black ink issue.

Not sure if it's appropriate to lump my question into here but would intermixing between GI-53 and HP GT52 inks considered safe or would it be more prudent to stick to canon inks in a canon printer/Flush the carts? i think i've read somewhere here that those have similar fading performance to the GI-53 but is priced similarly (atleast for C/M/Y) to the cheaper GI-50 set.

 

[Werwolf1985]

Not sure if it's appropriate to lump my question into here but would intermixing between GI-53 and HP GT52 inks considered safe or would it be more prudent to stick to canon inks in a canon printer/Flush the carts? i think i've read somewhere here that those have similar fading performance to the GI-53 but is priced similarly (atleast for C/M/Y) to the cheaper GI-50 set.

Mixing of the GT52 and GI53 worked for me in a HP 344/348 3-colour cartridge on my old HP 6840. The Gamut of the GT52 was a bit smaller for me. Check the Gamut plots at L50, comparing the GT52 in green vs GI53 in black on a cheap CC labelheaven paper.

 

[James Mike]

Mixing of the GT52 and GI53 worked for me in a HP 344/348 3-colour cartridge on my old HP 6840. The Gamut of the GT52 was a bit smaller for me. Check the Gamut plots at L50, comparing the GT52 in green vs GI53 in black on a cheap CC labelheaven paper.

That's reassuring to hear, makes me wonder if substituting yellow would make up the difference.