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Contents: ========= * Using "Top_Left" to calibrate your printer paper offsets. * Using !ChangeFSI for colour bit image printouts. * Print density variation from RISC OS 2. * Upgrading from RISC OS 3.00. * Changes to dot matrix printer definition files since RISC OS 3.00. * Using RISC OS 3.00 printer definition files with newer software. * Using new printer definition files with RISC OS 3.00. 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 (in App1) 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. Using !ChangeFSI for colour bit image printouts. ------------------------------------------------ The colour matching of the printer drivers is not always quite what it could be, and how good it is varies depending on the image being printed. If you are printing bit images (ie. sprites) to colour dot matrix pinters, an alternative is to use !ChangeFSI on the Support disc. This tends to give better colour matching (it is certainly different and vision is very subjective) and it gives you more control. Doing this requires care to ensure that !ChangeFSI and the printer drivers do not fight with each other. It also requires lots of memory for large images eg. you will need 8MB of memory to print full A4 at 360 by 360 DPI, and to print full size A3 at 360 by 360 DPI 16MB of memory is just about enough. Obviously lower resolutions and smaller output sizes will take less memory eg. 180 by 180 DPI full size A4 can be printed on a 2MB system and 180 by 180 DPI full size A3 can be printed on a 4MB system. Halving the resolution divides the amount of memory needed by four. There are two very important steps. The first is to set the "Output" window of !ChangeFSI to "Mode" 27 (or 31 ie. 4 bits per pixel, square pixels), "Use current mode" off, "Ignore pixel aspect" off, and select "Special:" and enter "D" in the special box. For the technically minded this tells !ChangeFSI to produce output in terms of 1 bit of each of red, green and blue ie. saturated colours. There is an exact mapping from this to the CMYK (Cyan, Magenta, Yellow and Key black) colour space used by the printer drivers and hence they can accurately print the output from !ChangeFSI. The other important step is to get the output from !ChangeFSI to be exactly the pixels that will be printed on the paper, so that the printer drivers do no scaling. You will use !Paint to print the output from !ChangeFSI, and in !Paint there are 90 dots to the inch (90 DPI). So for example if you are printing to a 9 pin colour ribbon printer at 120 by 72 DPI, you need to set the "Scale x" to 90:120 and the "Scale y" to 90:72 in the !Paint print dialogue box. For a 24 pin printer at 180 by 180 DPI it would be 90:180 and 90:180, and for the Canon BJC-800 bubblejet printer at 360 by 360 DPI it would be 90:360 and 90:360. Obviously to be able to do this the image needs to have been scaled correctly in !ChangeFSI otherwise it will be the wrong size, and will be distorted on a 9 pin printer. To get the scaling correct in !ChangeFSI, you need to look at how big in pixels your source image is, work out how many printer pixels you want to turn that into, and scale it appropriately. It is worth scaling something up in size, particularly if there are a lot of colours in the original (eg. a 24 bit master) as this will give !ChangeFSI more pixels to play with in the error diffusion and hence the colour matching will be better. For example you have a 24 bit master image which is 1384 by 1760 pixels in size. You are going to print this on A4 paper to a 9 pin printer at 120 by 72 DPI. A4 is 8.269 by 11.694 inches. To cater for the fact that the printer can't print to edges of the paper, knock 10% off which gives 7.517 by 10.631 inches. Multiplying those sizes by the 120 by 72 DPI resolution gives 902 by 765 pixels required as the output sprite size. In the "Scaling" window of !ChangeFSI, set "Ignore pixel size" to off and select "Custom" scaling. The top size (for horizontal or X scale) should be set to 902:1384 and the bottom size set to 765:1760. You may select either (or both) of "Mirror L/R" and "Mirror U/D" without affecting anything else, but if you select "Rotate" you will have to think carefully about the affect this will have on the pixel sizes. Print it straight first and then experiment later. The only other thing you need to do is apply whatever "Processing" you want in !ChangeFSI. It has been found that on 24 pin colour ribbon printers and high resolution inkjet printers (eg. Star LC24-200 at 180 by 180 DPI and Canon BJC-800 at 360 by 360 DPI) "Gamma correction" turned on and set to 3.0 works quite well. For a 9 pin colour ribbon printer (eg. Citizen Swift 9 at 120 by 72 DPI) the gamma correction needs to be less; around 1.6 to 2.0 works well. To lighten the image increase the gamma correction and to darken it decrease it. Changing it in increments of about 0.4 seems to get the right balance between changing too quickly or too slowly. You are unlikely to need any of the other "Processing" options unless there is something actually wrong with the original image which needs correcting, in which case it would also need correcting even if you were going to just use the printer drivers to do all the work instead of using !ChangeFSI. Set the printer drivers up to be the highest colour resolution you have enough memory for eg. 120 by 72 for 9 pin printers and 180 by 180 for 24 pin printers. You may use either "Colour, small halftone" or "Colour, dithered" for the "Quality:" field. In practice it has been found that "Colour, dithered" tends to give more pleasing results particularly at higher resolutions as it tends to smooth out the graininess introduced by using "Special:" of "D" in !ChangeFSI. You should try both and see which you prefer. "Colour, dithered" takes longer and needs more memory however. 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.) Upgrading from RISC OS 3.00. ---------------------------- When upgrading from RISC 3.00, you should re-assess which printer definition file to use. In some cases you will find that there is now a more appropriate printer definition file. If you choose to use the same file, you should use the new version of it (and the new !Printers of course) rather than the RISC OS 3.00 file. If you find that the file you were using under RISC OS 3.00 is no longer supplied and there isn't a more appropriate file in RISC OS 3.10, refer to the following table: RISC OS 3.00 file File to use with RISC OS 3.10 ----------------- ----------------------------- Epson.MX-80-IIa Epson.MX-80-II Star.Gemini-10 Star.Gemini-10 from RISC OS 3.00 Star.LC-10 Epson.EX-800 Epson.LQ-850 Epson.LQ-860 Epson.LX-86 Epson.FX-80 Changes to dot matrix printer definition files since RISC OS 3.00. ------------------------------------------------------------------ 1) The graphics "Line end 4:" field has become a "Zero skip:" field, and an associated "Skip resolution:" numeric field has appeared. These fields are usually 27,"$" and 60 for Epson compatibles and 27,"d" and 120 for IBM compatibles. This is used to perform leading zero suppression. 2) A "Set lines:" field has appeared in the graphics modes. This is almost always 27,"C". This is output BEFORE the "Page start:" sequence and is used to set the form length correctly on A4 fanfold, A2 and similar paper that the printer's DIP switches cannot accommodate. Previously this only worked for text printing, which always had a "Set lines:" field. 3) The graphics "Page end:" sequence has been split into separate "Form feed:" and "Page end:" sequences. This is so that if "Roll" paper feed is selected, the "Form feed:" can be omitted to prevent the paper from advancing. The "Page end:" sequence is output after the "Form feed:", and should set the printer's "top of form" (eg. with 27,"@"). Failure to do this may cause the printer to perform an auto perforation skip or other inconvenient actions later on when "Roll" paper feed is in use. 4) The character mappings have gained mappings for the Welsh characters WwYy circumflex, as character codes 129, 130, 133 and 134 respectively. These are almost always mapped as "W", "w",8,"^", "Y", and "y",8,"^" because they are not in any printer character sets. 5) The printer definition files are now compressed (!Squash format). 6) "Paper X offset:" and "Paper Y offset:" fields have appeared. These two numbers should be set to the amount of paper that has already gone past the print head before the printer can print anything at all. Thus they represent the section of the paper upon which it is physically impossible to print. The "Graphics margins" in the "Paper size" window in !Printers on the other hand are that section of the paper upon which you do not wish to be allowed to print. Note that if the "Top" and "Left" graphics margins are set to less than the "Paper Y offset:" and "Paper X offset:" respectively and you actually try to print something right up to the top left of the margins, then the image on the paper will be shifted down and to the right of where it is supposed to be, since you have tried to get the printer to print on the section of the paper that it physically cannot print on. Also note that the paper offsets are allowed to be negative, which they would need to be for a printer whose natural initial print position is above the top and/or to the left of the top left corner of the paper. Using RISC OS 3.00 printer definition files with newer software. ---------------------------------------------------------------- RISC OS 3.00 printer definition files will work with later versions of the software. However you should use a new file if possible, otherwise you will not get the performance benefits of leading zero suppresion, the form length will not be set properly for graphics printouts, the "Roll" paper feed option will not work properly and the Welsh text characters will not be mapped. Additionally the output will appear too far down and to the right on the paper due to there being no paper offsets in old files. If you created your own printer definition file with !PrintEdit, then you can edit your file with the new version of !PrintEdit and upgrade it to use the new features documented above. Be aware that not all Epson compatible printers support 27,"$" (used in "Zero skip:"). Also you must go into every graphics resolution window and click "OK" in them all before you enter any paper offsets. Otherwise the paper offsets will not work for any resolution that you do not click "OK" in, since the data format will not have been upgraded for that resolution. Using new printer definition files with RISC OS 3.00. ----------------------------------------------------- The printer definition files are now squashed internally, so first of all you will need to change their filetype to Squash, and then run the files through !Squash which will then give you unsquashed printer definition files as output which can be used by RISC OS 3.00 systems. The most likely problem you will encounter using the files is that you will not get a form feed at the end of each graphics page, because the RISC OS 3.00 printer drivers don't know about the separate "Form feed:" string. This can be resolved by using !PrintEdit to put the "Form feed:" string at the START of the "Page end:" string. Either an old or a new !PrintEdit will do, but if you use an old one the graphics definitions you edit will be downgraded to the old format, losing most of the new data. If you use a new !PrintEdit, you will get a squashed printer definition file as output, regardless of whether the input file was squashed. The RISC OS 3.00 printer drivers will ignore all of the new fields documented above, except for the Welsh text character mappings. (Actually using the Welsh characters on RISC OS 3.00 could be tricky.) The Apple ImageWriter II printer definition file will not work on RISC OS 3.00 since it uses a new module called PDumperIW which was not supplied with RISC OS 3.00. PDumperIW does not work on RISC OS 3.00.