Contents: ========= * General purpose printer definitions. * Using "Top_Left" to calibrate your printer paper offsets. * Print density variation from RISC OS 2. * Updating !Printers General purpose printer definitions --------------------------------------------------------- The "Text" printer definition file is a very basic raw text printer definition file. It assumes virtually nothing - it uses form-feed (12) carriage-return (13) and line-feed (10) and the normal ASCII printable characters from 32 to 127. There are text highlights. ISO Latin 1 international character mappings are supplied, but every character is simply mapped to the closest available normal ASCII character. You would only use this file when attaching an unusual printer for the purposes of doing text printing only eg. daisy wheel printers, golf ball printers, line printers etc. The graphics resolution in this file is a dummy as all DP printers must have at least one graphics resolution. (It is in fact an MX-80 Type II resolution). The "PostScript" printer definition file should be used if you cannot find a definition file for your PostScript printer. It defines a colour PostScript printer with a resolution of 300 by 300 dpi, with the standard 35 fonts that Adobe provides. The "PstScrptFP" printer definition file should be used if you have a PostScript printer with a fast parallel interface and your computer has suitable hardware. In all other respects, it is identical to the "PostScript" printer defintion file. Using "Top_Left" to calibrate your printer paper offsets. --------------------------------------------------------- The "Printers.Top_Left" printout file can be used to calibrate the position of output on Epson and IBM compatible dot matrix printers. To do this, you should first ensure your printer is in its default state eg. switch it off and switch it back on again, and feed paper into it if necessary. Then send the Top_Left file directly to the printer. The easiest way to do this is to set !Printers up for printing to your printer, and then drag the "Top_Left" file icon onto the icon for your printer on the icon bar. Alternatively, you can use the command line; the command "*Copy Top_Left Printer:" will send the file to the printer, assuming you are in the Printers directory and the print destination has already been set up correctly (eg. by !Printers). On the paper there should be a small vertical and horizontal line (like an inverted "L") close to the top left corner of the paper. Start !PrintEdit and drag the printer definition file you wish to use into the !PrintEdit window. Measure the distance from the left hand edge of the paper to the left hand edge of the inverted "L" mark (do not measure to the middle of the mark). The distance you have just measured is the "Paper X offset" for your printer, so you should enter it into the "Paper X offset:" field in the !PrintEdit window. Now measure the distance from the top of the paper to the top edge of the inverted "L" mark (again do not measure to the middle of the mark). This distance is the "Paper Y offset" for your printer, and should also be entered in the !PrintEdit window. Now click the MENU button in the !PrintEdit window (avoiding the "Graphics modes:" icons or you will get the wrong menu), and use the "Save" option to save your customised printer definition file. It is recommended that you do not overwrite your master printer definition file. Either make sure you have backups, or save your new file somewhere else. Now quit !Printers, restart it, and load in your new printer definition file using the "Printer control" window. Printed output on your printer should now appear in the correct position. Print density variation from RISC OS 2. --------------------------------------- You may find that printouts are lighter or darker under RISC OS 3 than they were in RISC OS 2. This is usually due to a change in the amount of interlacing being performed ie. the number of passes the print head makes over the same section of the paper. For example a Canon BJ-300 printer under RISC OS 2 with !PrinterDM set to "EPSON LQ-850 compatible (360 by 360 dpi)" and the printer set to Epson LQ emulation mode will make two passes over the paper due to using vertical interlacing. The same printer under RISC OS 3 with !Printers using the Canon.BubbleJet file set to 360 by 360 DPI and the printer set to IBM emulation mode will only make one pass over the paper. So the printout will be lighter, but on the other hand it will take less time to print and the quality will be higher since no interlacing is being used. Also the ink cartridge will last longer. In this example running the printer in Epson LQ emulation mode with the Epson.LQ-860 file set to 180 by 360 DPI will give results which are almost identical to the RISC OS 2 configuration. In the general case, if you use 360 by 360 DPI in any printer definition file which gives true 360 DPI vertical resolution (non-interlaced), then this will give lighter print than any of the 360 by 360 DPI standard Acorn !PrinterDM settings, which are all interlaced. The files which use true 360 DPI vertical resolution are Canon.BJ-130e, Canon.BJC-800 (usable with Star SJ-48) and Canon.BJ-130e. Switch to a 180 by 360 DPI resolution in a more standard file (eg. Epson.LQ-860) if you need the interlacing to get darker print. Conversely take an Epson LQ-850 printer under RISC OS 2 with !PrinterDM set to "EPSON LQ-850 compatible (360 by 360 dpi)". This again will make two passes over the paper. The same printer under RISC OS 3 with !Printers using the Epson.LQ-860 file set to 360 by 360 DPI will make four passes over the paper since it is now horizontally interlaced as well as vertically interlaced. (In fact RISC OS 2 never really achieved 360 DPI horizontal resolution since it didn't interlace it and the printer will not print adjacent dots. The only benefit this gave was 360 DPI positional accuracy of left hand edges.) So the printout will be darker and the resolution will be better, but on the other hand it will take longer to print and will wear the ribbon out faster. In this particular example using 180 by 360 DPI in !Printers will give results which are almost identical to the RISC OS 2 configuration. In the general case, if you use any resolution in any printer definition file which is horizontally interlaced, this will give darker print than the same resolution under !PrinterDM. In practice this is 240 DPI horizontal for 9 pin printers (240 by 72, 240 by 144 and 240 by 216) and 360 DPI horizontal for 24 pin printers (360 by 180 and 360 by 360) although not all of these resolutions are available as standard in !PrinterDM. If you need to get the same print density as you did on RISC OS 2, halve the horizontal resolution you are using to 120 DPI or 180 DPI. If the extra positional accuracy of left hand edges that RISC OS 2 gave you turns out to be important, then edit the horizontally interlaced graphics resolution you are using (eg. 240 by 216) with !PrintEdit and change the "X interlace:" field from 1 to 0 which will disable the horizontal interlacing. (Note that you cannot simply disable vertical interlacing in a similar manner. Other changes would be required.) Updating !Printers ------------------ It may sometimes be necessary to update !Printers, either to incorporate upgrades or to modify some support information to drive a new printer. You should refer in the first instance to any release notes with the update. However, the means of updating differs slightly, depending on the version of RISC OS. Some versions may have !Printers on disc (in the Printing directory), and some in ROM (accessed from the Apps icon on the icon bar). For versions of RISC OS with !Printers on disc, you can easily add to or update files within the !Printers directory. For example, a new printer palette could be added to the !Printers.Palettes directory. For versions of RISC OS with !Printers in ROM, updates should be placed in the !Boot.Choices.Printers directory on disc. For example, a new printer palette could be added to the directory !Boot.Choices.Printers.Palettes. You may have to create the directories Printers and Palettes within !Boot.Choices, depending on any updates or choices which have already been made. The ROM-based files themselves can be found in Resources:$.Resources.Printers (accessed from Open '$' on the Apps icon menu).