Why do some inkjet printers insist on using all inks for cyan,magenta, etc.?

[Enrique]

This is just a general wondering of mine, sometimes to calibrate my inkjet printer I'll print out a grid of PMS tones, including straight CMYK. But when I look at it with a loupe, the CMYK squares have specks of other ink colors in them (i.e. there's cyan in the 100% magenta square).

I've noticed this on different brands of printers... why does this happen?? Do all inkjets do this? I haven't tried this on higher end printers like HP Designjet, Epson 9600, etc., only consumer and prosumer printers.

 

[Cliff]

Vutek Pressvu and Ultra Vu as well as Fuji/oce do not do this,.. no printer should do this,... for fun print the patch then turn off all other heads ( if possible) and see if there is a differance but I am sure its you cal in the rip or printer settings. a 100% C, M Y or K will be just that, but light mixed colors will be just that mixed. Usually the rip cal and or linerisation will take care of that. That said ,... it is normal for pure ink colors to have another tone such as a yellow bias Magenta but you will not see yellow and magenta dots in a pure Magenta patch.

 

[Maximus323]

Question: Do you send this test from a computer or directly from the printer itself (built in test)?

If it comes from the computer, there is probably a colour conversion performed from either the print driver or the RIP software and it adds some level of colour to even the pure hues. If it comes directly from the printer, it is probably programmed this way or there is definitely a problem with the printer.

 

[Enrique]

This would be a test pattern I created. I did at some point think it was some driver glitch, I'm not sure what difference it makes because the prints came out the same but I've tried it with "Let printer manage colors" both on and off.

This isn't really ruining anything for me btw, it's just bizarre that I make a big square with 100% yellow and there are magenta and cyan dots within, and things like this burrow into my brain

 

[Cliff]

This would be a test pattern I created. I did at some point think it was some driver glitch, I'm not sure what difference it makes because the prints came out the same but I've tried it with "Let printer manage colors" both on and off.

This isn't really ruining anything for me btw, it's just bizarre that I make a big square with 100% yellow and there are magenta and cyan dots within, and things like this burrow into my brain

Exactly the rip and or driver is creating a color conversion. There should be a print solid color in the menu of the printer or at least you should be able to run a relinerisation or cal from the rip software. basically it sound like the color profile is messing up your color.

 

[M&M Displays]

Most digital color printers do this UNTIL you have built the proper profile. Our QS2000 would add about 3-4% magenta to make process yellow. Profile the machine using the proper software and the issue goes away

 

[Cliff]

Most digital color printers do this UNTIL you have built the proper profile. Our QS2000 would add about 3-4% magenta to make process yellow. Profile the machine using the proper software and the issue goes away

Thats more or less whats happening, built your profile, If using efi rip there are also dozens of check boxes as well as the ones in you app software. ie ICC etc

 

[Maximus323]

Well, then what happens is that either the print driver or the RIP is modifying the colour of your file to adapt it to your printing condition. Most inkjet ink manufacturers produce ink that have amazing hues that exceed most standards of colour management. To make sure you don't obtain prints that are overly saturated, they tone down these pure colours through colour management. That is why you are seeing a bit of extra ink in totally pure hues.

 

[M&M Displays]

You might also want to try a file using PS "LAB" color, instead of CMYK or RGB. You can tweak the LAB file and get amazing color.

 

[Cliff]

Sure that could work , but you really need to strip off anything the printer is adding otherwise you will be dealing with too many variables caused by multiple conversion being applied. Get that printer to a known point, ie, no printer applied correcting, then build a good profile for each material and or qualities ( res etc ) . then use that profile applied in your app. Normally it takes some time but its worth it.

 

[Mac-S]

I think your problem is this:
100 % cyan in your desktop application ( photoshop...) is not the same as 100 cyan on your printer.
I find that this is easiest to see in the yellow areas. Very often you see meganta drops in there. Because your printer / RIP is trying to simulate the yellow of you Photoshop ICC.( A warmer yellow )
If you can disable all icc usage in your RIP the problem will go away. This is offcourse not the right solution. Good profiles is as always the answer.

 

[imagesetting]

Something is adjusting the outout colour for you, RIP, Printer software, etc, the ink in the cart is 100% of its colour.
As explained you will get very light tints of other colours in your primary patches as it adjusts colours to fit a profile, for example most inkjet yellows are far more vibrant than Litho yellow, so profiled printers will add tints of other colours to dull it down so it matches when trying to match a litho print. Some inkjet inks can be far too saturated - and hence the speckles to adjust by just a few % - or what ever value is deemed necessary to match whatever target is measured.

Exhibition Display Services, Cromalin Proofing & Prepress

 

[Enrique]

Thanks guys, you've given me a lot to go on I'll see what happens.