Graham Harris Graham | Ink Jet Printing

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With a cheap inkjet printer & a few clicks of the mouse, it is possible to print surprisingly high quality images at home. But the ink cartridges, especially for the home printing market remain so absurdly expensive that I hope to persuade you to consider Type-C printing instead.

(I can't keep up with currency markets so for illustrative purposes only, have stuck with a Pound Sterling/US Dollar exchange rate of 1:1.51)

Inkjet Technology

Inkjet prints are produced from a digital file using either the mature continuous ink jet (CIJ) technology or the more modern drop-on-demand (DOD) technology. Both spray a microscopic layer of pigments or dyes onto a substrate; typically paper for photographs which itself has been coated to hold the ink solution without bleeding until it dries. The dots are so small, that they are invisible to the naked eye but the effect is to produce continuous tones of colour so that we see a photograph.

Ink Spraying

Most home printers use a thermal DOD inkjet process to create copy or an image via one or more ink cartridges in which heat is applied to the HPDesignjet Z6800 printing head causing ink to be ejected onto the paper. A more sophisticated but expensive technology called piezoelectric DOD, delivers drops of ink by using a voltage to change the shape of a Piezoelectric material. This creates a positive pressure that pushes the ink through a hole & onto the paper. Currently, piezoelectric DOD technologies are mainly found in commercial printers & rarely in budget priced home printers due to their higher costs.

Home vs. Business

One other key difference between home inkjet printers & commercial inkjet printers is the number of ink colours used to create an image. For colour photographs, home printers typically use a black ink in combination with cyan, yellow & magenta (CYMK colour space). I show in another article the meaning of CYMK colour space & compare it to other colour spaces like Adobe RGB & sRGB.

Some ink cartridges designed for home use combine the three colours into a single cartridge so that only two ink cartridges are actually required. Some higher priced models, specifically aimed at the home photographic market require two blacks & a gloss enhancer in addition to the three primaries of cyan, yellow & magenta.

Bigger is Better. Right?

But commercial inkjet printing machines can easily use up to eight different colours, sometimes more. E.g. the HP Designjet Z6800 is a 60 inch wide machine that requires eight ink colours to operate -

1. matt black HPDesignjet Z6800 ink cartridges

2. photo black

3. light magenta

4. magenta

5. chromatic red

6. yellow

7. light grey

8. light cyan


Ink Costs

As of January 2016, in rip off Britain, each 775ml cartridge costs about £209 ($316) while the printer will set one back £16,000 ($24,000) before trade discounts. So in addition to the huge cost of the printer, one needs to spend 8 x £209 ($316) = £1,672 ($2,528). And don't forget the additional maintenance cartridge. That's another £209 ($316). Ouch!

Meanwhile Epson's smaller 44 inch wide Stylus Pro 9900 UltraChrome HDR costs "only" £6,269 ($9,466) but it needs 11 different inks to operate. The best price I could find for a 350 ml cartridge is £110.59 ($166.99) delivered. So one will need to spend £1,216 ($1,836) plus £6,269 ($9,466) = £7,485 ($11,302) just to get the printer fired up. Ouch again! 


Although one main advantage of inkjet technology is that many materials, not just paper can be printed; vinyl, aluminium, plastic, etc. & printing  at home is certainly convenient. But regardless of inkjet technology or cost, the principle remains the same; an image is created by coating a substrate with a thin layer of colour made up of EPSONStylus Pro 9900 millions of microscopic ink dots.

And the visual effect can be further modified depending on the substrate. Papers designed for inkjet photographic output are usually treated or coated to alter a number of parameters such as smoothness, gloss & absorption in order to affect the image's colour gamut, colour balance, saturation & apparent sharpness for example.

Gold Standard

But I can't stop thinking about the costs. The best price I can find for the commonly used Canon PG-510, a 9ml black ink cartridge for home document/photo printing, is £11.50 ($17.37) delivered from Amazon. That works out at £1.28 ($1.93) per ml or an eye watering £1,280 ($1,933) per litre.

An HP 773C Photo Black used in the Designjet Z6800 mentioned above, costs £208.90 ($315.44) for a 775 ml cartridge. That works out at £0.27 ($0.41) per ml or a more reasonable yet still mystifyingly expensive £270 ($408) per litre. The Epson Stylus Pro 9900 shown on the left, uses smaller 350 ml cartridges than the HP and its unit costs work out at £0.32 ($0.48) per ml or £320 ($483) per litre. That's £50 ($76) more than the HP but still £960 ($1,450) per litre less than the Canon ink designed for the home.

Moving down the wish list there's the 6-colour, Canon PIXMA iP8750 retailing for about £230 ($347). I've found the coloured inks from Canon retailing for about £12 ($18.12). Each cartridge contains 12ml while the standard black holds 25ml. So the coloured ink for this little beauty costs only £1.00 per ml or £1,000 per litre.

Unit Cost Comparison

  Ink Cartridge Ink Volume Unit Cost Cost per ml Cost per litre
  Model (ml) (£) (£/ml) (£/l)
Canon PG-510 9 11.50 1.28 1,278
Canon PGI-550PGBXL 12 12.00 1.00 1,000
Epson T596100 350 110.59 0.32 316
HP 773C 775 208.90 0.27 270


The Rip Off Model

What appears to be happening is that commercial printers are sold at near full cost or above. And the inks are sold at near 'normal' market rates although quite how anyone can still justify charging low margin print businesses up to £316 per litre is a mystery. 

Canon PG-510Only £1,278 per litre  Price Fixing

The domestic market is the complete reverse. Manufacturers are effectively selling their printers at or below cost but then gouging their customers by forcing them to buy their own inks. They also attempt to stop 3rd party ink suppliers from getting in on the action by embedding microchips in the ink cartridge to make it impossible to reuse them. Sound familiar?

But no matter which business model you look at it, the price of ink is outrageous. Consider that an oil company intending to extract from the North Sea, has to invest hundreds of millions of dollars just to take a risk to find the stuff. Yet the retail price of a litre of unleaded, even in the notoriously expensive UK, only costs about £1.05 ($1.59) per litre.

I get it; the volume of oil extracted is huge but it also has to be piped to shore, refined then distributed to retailers with everyone in the supply chain needing a cut of the profits, including the greedy government. Think about that for a moment. One commercial litre of ink, costs above 200 times the price of one litre of petrol. While one litre of ink is sold to the home market at above 1,000 times the price of a litre of fuel.

The Secret Formula (Sshhh ... it's water!)

Perhaps the high costs might be explained away because ink is actually made up from rare & exotic materials? Well, I'm going to break some bad news; water makes up at least 50% of the volume & is often more than that. The remaining 50% is made up from colourants (dyes or pigments), co-solvents, humectants to keep things CANON-PGBK-550Only £1,000 per litre ! moist, fixatives to minimise smudges & smears, surfactants to help keep the cartridge nozzle clean, resins to carry & disperse the colourants, biocides/fungicides to give the ink a longer shelf life & buffering agents to stabilise the pH. So no Kryptonite or ground up ivory then.

Cost Of Goods

Now, I spent the first 25 years of my life in global manufacturing so I have a good idea how much it costs to make a cartridge & that the difference in cost of goods sold (materials, labour, storage, overhead expenses & depreciation) between a 9ml cartridge & a 775 ml cartridge is negligible. Furthermore, highly automated cartridge production is achieved in low labour cost economies, so COGS will be relatively small compared to the combined unit costs of R&D, sales & marketing, admin (HR/IT etc), rent, debt & finally dividends & taxes.

Why Bother?

It's blatantly obvious then that inkjet printing is needlessly expensive. The costs are simply not reflected in the prices which means that the market is wholly & artificially distorted. Furthermore, each different type of paper one prints on, whether at home or via a commercial lab, needs its own colour profile if one has any hope of reproducing an accurate image. So test prints & cartridge cleaning cycles consume a significant amount of ink & paper. A commercial lab spreads this cost across all its customers. But at home, one eats the whole cost all by one's self.

Yes, home printing is very convenient but once the yield (what one ends up with after test prints & ink is deducted) is factored in, one might easily conclude that it is more economical to have a lab produce a proper, silver halide photograph instead.