Epson P900 using excessive amounts of Gray Ink

[Peteprints]

Hello,

Printing images (photos of my paintings) on my Epson P900 is using excessive amounts of Gray and Light Gray ink cartridges. I'm having to change these two at a rate probably 3:1 of any other color. When I order ink, I'm buying 3 or 4 times more Gray and Light Gray cartridges than the others.
1. My images have a broad range in the color spectrum. If anything they're mostly shades of blue or cooler colors. I'm not printing any black and white photography or anything like that.
2. I print mostly on roll paper (luster photo paper) and (matte) canvas, and occasionally borderless on pre-cut paper sizes.
3. I'm printing 150-200 prints per week ranging from 8x10 to 16x20, the large majority are 11x14 or smaller.
4. This is my second P900 and they've both had this situation.
5. I'm using Lightroom Classic in Adobe CC for printing. I rarely make any adjustments or use any "Develop" panel tweaks.

I haven't been able to pin point something that would explain the high usage of the Gray and Light Gray ink. I've looked through the printer settings and print dialogue and haven't found a setting that might explain it... searching online I haven't really seen a big contingent of people with the same problem either.

Any suggestions that may narrow it down would be helpful! If it's not something I can change I'd at least like to make sense of it and maybe minimize it. The cartridges aren't cheep!

Thanks for your time!

www.petekornowski.com

 

[Ink stained Fingers]

If it's not something I can change I'd at least like to make sense of it and maybe minimize it. The cartridges aren't cheep

There is a simple answer to it and a more detailed one,

- you should not just look to the usage volume of the gray inks but to the total volume you are using with your printer , you can assume that the usage of gray inks actually reduces the total ink volume and does not increase it, and there is nothing you can do about it , it is all driven by the driver in combination with the firmware.

- You can define a color with 3 variables - e.g. the pretty common R G B values - or the CMY values or separating the lightness and the color values with the L a b parameters - it's all with 3 independent variables, and there are more of such color spaces like the HSL color space - hue - saturation - lightness. None of these color spaces use more than 3 variables but you have plenty more actual inks on your printer which requires the driver to separate the color input from your images into many more - 6 or 8 or 10 ink channels, a process you don't have any control over. Just assume a simple example - a medium gray - RGB = 128 which prints as a neutral color with 3 inks on a simple 3 color printer. A printer with gray inks can separate the lightness value of such gray and just print it with the gray ink - and no other color. This already indicates that the overall ink volume of gray - 1 ink - is less than printing such gray with 3 inks as an RGB combination. And now assume any non-saturated color - you can separate that into a lightness value and print that with gray and just add the color as needed - just to create the color impression and not the lightness of that color. It is obvious that you cannot separate lightness and color values completely in the actual printing process but to a high degree. You find an expression 'UCR' - undercolor removal - used in the printing environment - a function you typically can do if you convert RGB data into CMYK data - K - there is suddenly an addtional color value - the black channel printing/dithering the necessary lightness of a color.

Printers like the P900 are even more sophisticated and do not just use a black ink channel but one or more gray ink channels which gives more variables for the driver to split a color into.
You can do that all for yourself with RIP software which bypasses the driver altogether but I'm not sure that there is much benefit for you with the P900 using OEM inks.

If the cost of ink is your concern you may have a look to refill, but that might be blocked in your region, or you look to a larger printer with larger cartridges like the Epson P5000, the actual ink price drops on printers with larger cartridges. Your print volume is quite high already so the P5000 might be a good alternative for you.

 

[Peteprints]

Thank you for a thoughtful reply. So essentially grays are used to make nearly every color variation. Makes sense.

I'd love to upgrade to a larger printer in the future for multiple reasons. Right now I have some physical space limitations. Trying to maximize what I've got!

Thank you again for the great info!

 

[Ink stained Fingers]

So essentially grays are used to make nearly every color variation. Makes sense

you can - but most drivers would not go to the extreme with the gray color replacement , there are color ranges - those with less color saturation - but Canon or Epson don't publish any information in which color ranges they do it and to which extend. But you don't have any control over it unless you would use RIP software.