Computer Laboratory

Producing posters using gum

The Computer Laboratory (T&R) has an HP DesignJet T1200 inkjet printer/plotter (gum) capable of producing colour images on paper from A4 to A0 in size. This printer has two paper rolls permanently loaded, usually these are 42 inch wide (slightly wider than A0) and 36 inch wide (slightly wider than A1), although other sizes may be loaded depending on the availability of paper rolls from our suppliers. The printer will automatically select the correct width for your print. Thus it is not necessary to continuously swap paper rolls around as with our previous large-format printer. Reloading paper rolls is straightforward – follow the control panel instructions. The paper format we buy is always HP Coated paper.

NB. Some other printers (eg sycamore, mulberry) can print A3 in colour, and others (eg palm, poplar) can print A3 Black and White, so if you need A3 please use one of them instead – it's cheaper and easier.

General advice

We operate an access control list for gum to prevent people from accidentally printing the wrong sort of job (eg code listings). If you wish to be added to the access control list, contact printing@cl.cam.ac.uk.

Printing artefacts can appear if printing from Unix. Specifically, large areas of dark colour (particularly blue, purple or dark green) suffer from banding – horizontal stripes with slightly varying colours. If your image does not include areas of flat dark colour larger than a 3 or 4 centimetres then you can print from Unix. Otherwise you will get far better results printing from Windows.

Printing from UNIX

You get better results from Windows, it is strongly recommended you use Windows instead. Unix users should consider printing from a Windows environment, use cl-rdesktop if you do not have direct access to a Windows machine. However, if you insist on using Unix, read on...

If printing PDF it is best to print directly from acroread, see 2.1 Printing PDF files under UNIX.

Windows application formats (.doc, .ppt, etc) can be printed directly from Open Office if you have it installed. It is straightforward, and similar to printing from acroread.

Postscript can be printed directly from the command line with lpr. If your document is A4 then you can pick the size you want by giving options to lpr. To scale the output to A2:

lpr -Pgum -A2 filename.ps

Likewise for -A0, -A1 and -A3. Note, however, that the Unix scaling options are severely limited, so if you want a non-standard scaling (eg if your poster was produced at a "custom" size rather than A4, or if you start with something which is already scaled up) then it can be extremely difficult to get the scaling right. It is also difficult (but not completely impossible – one for a CUPS guru!) to access the other less common options (eg rotation, colour manipulation) directly from the command line.

Printing PDF files under UNIX

It is difficult to give general advice here as what you will see will vary from Linux distribution to distribution, and across versions of Adobe Reader (acroread). The following works on a recent Adobe Reader 9 version (Ubuntu):

  • Select Print... from the File menu
  • Select gum in the Print popup. It should say "gum is ready" under Status.
  • Click on Properties
  • Under Options select Print Document on and then whatever size you require under Choices
  • Under Options (scroll down) select Media Size and then whatever size you require under Choices
  • Click OK (or go on selecting options if you wish, although these are probably best left to experts)
  • If your PDF file is already scaled to a particular size then you should set Page Scaling to None, otherwise you should set Page Scaling to Fit to Printable Area. Either way you should now see your poster displayed properly in the Preview area with no areas grayed out and the correct dimensions displayed for the size of paper that you want
  • Select Auto Rotate and Center
  • Select Portrait or Landscape
  • Click on OK

Printing from Windows

  • From within whatever application you are using select Print... (usually from the File menu).
  • Select gum in the Print popup. It should say "Ready" under Status.
  • Click on Properties – this will bring up the gum Document Properties window
  • Select the Paper/Quality tab
  • Set the Document size to whatever you want. Note that if you select "More..." you get a large selection of possibilities, including some with "no margins", e.g. A1 no margins. Some of the sizes you can select will conflict with the defaults so you may get a popup window complaining about these conflicting options – tell it to fix the conflicts (which is probably what you want) by clicking OK, or cancel. (Note that it is safe to print with no margins as the paper we buy is larger than A1, A0 etc – so printing with "A1 no margins", for example, will not come right up to the physical edge of the paper.)
  • Select the Printing Shortcuts tab
  • Select the GIS printing shortcut (other selections may work just as well although you might see warnings about incompatable options, which you can ignore).
  • Set the Orientation to whatever you want
  • Set the Paper Type to "HP Coated Paper"
  • For most documents set the Print quality slider to somewhere half way along the line (the default). However, if your document features large areas of flat colour, particularly black or dark blue, then move the slider along to the Quality end. Black or dark blue can be prone to banding - increasing the Quality puts more ink on the page which gets rid of the banding but will take longer and can make the paper so wet that it cockles (wrinkles and creases).
  • Click on OK, the gum Document Properties window will go.
  • If your file is already scaled to a particular size then you should set Page Scaling to None, otherwise you should set Page Scaling to Fit to Printable Area. Either way you should now see your poster displayed properly in the Preview area with no areas grayed out and the correct dimensions displayed for the size of paper that you want
  • Select Auto Rotate and Center
  • Click on OK

If the result has incorrect colours (this happens sometimes with PDF files in particular) then add the following step to the above procedure:

  • on the gum Document Properties window, select the Color tab
  • Select the Application managed colors button instead of the Printer managed colors button

Lamination

We have a large format laminator capable of laminating posters up to A0. The laminator takes some skill to use and works at a high temperature, and as such is not suitable for use by untrained lab members. If you wish to laminate a poster please email printing@cl.cam.ac.uk and allow enough time for the poster to be laminated by one of the trained systems staff during usual office hours. It may take half an hour or so for the laminator to heat up to the required temperature, thereafter it is quite quick. DO NOT UNDER ANY CIRCUMSTANCES ATTEMPT TO USE THE LAMINATOR YOURSELF.

Note that our facilities are available only to members of the Computer Laboratory. If Google has bought you to this page from somewhere else in the University then you need to contact the Computing Service Printing and Illustration Service (PandIS) http://www.cam.ac.uk/cs/media/pandis/