Interested in writing a cups driver...

Collin Day dcday137 at
Thu Sep 4 23:26:12 PDT 2008

Hello all,

I own an HP Photosmart Pro b8850.  I am using it to print photos.  I know that there are PPD's and drivers out there that work with this printer, but none seem to have everything that I want.  For example, the HPLIP does not yet support using just the gray inks for photos (but they are working on it) and they have no plans to support 16 bit images - everything has to be moved to 8 bit.  I prefer to edit and do work in 16 bits.  After a little research, it seems cups would support a 16bit/channel input (I think - please correct if I am mistaken).

Anyway - point is I figure if I want it done how I want it done I should just do it myself, and then share the results with the world.  I have been trying to read the documentation and follow with how CUPS, PPDs, etc. all glue together and it is clearly not trivial.  I will probably have more questions in the future, but for now I was hoping I could ask a few and maybe see if someone would be interested in just pointing me in the right direction.

Q1.  HP says that the printer uses PCL3 GUI, but a lot of the drivers I see indicate PS driver types.  Should I try to use PCL or is PS the preferred method?  Does anyone know the advantages and disadvantages - all I can read right now is that PS is good for mainly vector images while raster is the way to go if you are interested in printing photos (that would be me).

Q2.  I can't seem to figure out how/where you would tell the printer to use only certain inks - I see RGB and CMYK mentioned a lot, as well as ICC profiles for different numbers of inks.  Just for simple purposes, does anyone know approximatley hoew you would go about printing a B/W photo with just gray inks so that you are not using any of the CMY colors?  Right now, when I print grayscale out of something like Cinepaint, it has a slight green cast which is common with CMYK printing.  With the HP supplied driver on Windows(which I hate using, and it only supports 8 bit images unless you have Photoshop, which I do not) I can seslect gray inks only and get something that looks more like a true B/W print.

Anyway - sorry for the long post - thanks for your help!


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