Understanding Printer Drivers and Bits per Channel

[Gerry LOncle]

I will start this thread with an expression of gratitude for Cambridge in Color for their forums and amazing information and technical knowledge. I am truly overwhelmed as I did not expect to see anything so comprehensive on Photography anywhere.

So for my first post inquiry: I have been reading here ravenously on Bits per Channel or Bits per Color (BPC) and it is a fascinating topic and well explained here as it pertains to displaying colors on display devices, and I pretty much understand that.

What I don't fully understand is the BPC as it pertains to the printer drivers and what is finally sent to the printer, and how the output might vary with different images.

For an example, I am on a Windows Machine (Win 10 Pro-64) with a Canon Pro-100 printer.

Canon provides a Pro-100 driver which, I understand, is an 8 BPC driver.

Canon also provides a driver called XPS, which they claim is a 16 BPC driver and can only be installed if the original 8 BPC driver has already been installed. I have no idea how they work, but I am just looking for best printer output results for any specific image.

Now, what I have been led to believe from elsewhere (and I don't believe it) is that the Canon Windows 16 BPC driver is not a true 16 BPC driver, but interpolates data it gets from the application, even if the application is using 16 BPC, and that even the XPS driver is really 8 BPC.

Also it has been stated to me from elsewhere that the Mac printer drivers are native 16 BPC, and I won't dispute that since I have no idea and don't have a Mac, but it was also stated that neither Epson nor Canon has developed a 16 BPC driver for Windows (which again I don't believe), and I know for sure that the Windows OS at least has that capability for 16 BPC since it released Windows 3.1.

So can anyone here enlighten me on the Canon Windows XPS Pro-100 driver, or Epson Windows printer drivers at they pertains to 8 or 16 BPC capability?

[Manfred M]

First of all I think you don't seem to understand how printing differs from screen displays

An individual screen pixel can be lit up (on an 8-bit system) with 256 discrete channels. In a printer, either the printer deposits some ink or does not deposit any ink; there are no degrees of variation and there aren't any specific colour channels. On my Epson P800, I can deposit up to 8 different droplets of ink; black, gray, light gray, magenta, light magenta, cyan. light cyan and yellow. There is a special condition where no ink is deposited as well, so really 9 different ink / no ink combinations here (9! = 362,880 combinations). I don't need even 8-bit data to describe this amount of colour.

I get no choice of bit depth for my output to printer via the Epson print dialog. The driver makes all those decisions for me.

[DanK]

So can anyone here enlighten me on the Canon Windows XPS Pro-100 driver, or Epson Windows printer drivers at they pertains to 8 or 16 BPC capability?

The standard driver is 8-bit, and the XPS driver is 16-bit. The standard driver is installed automatically when you install the printer. The XPS driver must be installed separately. once it's installed, you'll see two canon Pro-100 printers in the Windows print drop-down box, one of which will be labeled XPS. Select that if you want the 16-bit driver.

I routinely use the XPS driver to play it safe. When I had a problem with a previous Canon printer, I discovered in doing test runs that the printer does behave differently with the two drivers. That said, I doubt you'll see appreciable differences in practice most of the time. Some of Canon's own printing software can only use the standard driver, but Lightroom, Photoshop, and other applications will give you the choice.

[Gerry LOncle]

Thank you Dank, for confirming the XPS Driver is 16 BPC.

I have had these drivers installed for some years and can confirm the installation requirements.

I generally use only the XPS driver especially when I have an image with a large expanse of a gradually changing color. I find it easier not to have to think about if the 8 BPC driver is good enough or if I need the 16 BPC driver.

[DanK]

Thank you Dank, for confirming the XPS Driver is 16 BPC.

I have had these drivers installed for some years and can confirm the installation requirements.

I generally use only the XPS driver especially when I have an image with a large expanse of a gradually changing color. I find it easier not to have to think about if the 8 BPC driver is good enough or if I need the 16 BPC driver.

Exactly my view. I see no reason to bother with the 8-bit driver. I have all of my print templates all set to select the XPS driver automatically.