How to print a kit
(or the path from electrons to paper)
What printer to choose?
We have three choices:
- Laser (works by baking a fine powder - toner - into the paper). In most cases, laser gives the best colours, sharpest outlines and glossiest surfaces (good for cars or planes, bad for architecture). Another advantage is that the colours don't change over time and they don't dissolve in water. A disadvantage is that the toner layer is not very flexible and it can crack or fall off when cut, scored, bent or burnished (that's my experience; maybe with a high-quality glossy paper it would be something completely different). And the glue doesn't catch on it very well. And the print is quite expensive.
- Inkjet (works by spitting tiny ink droplets onto the paper). Sort of sweet spot middle class used by most modelers. An advantage of ink over laser is that it soaks into the paper, so it doesn't mind bending, cutting or gluing. The surface is usually matte and the quality varies with both the printer and the paper used (high-end photo paper is the best). Disadvantages are poor resistance to water and sunlight and the ability to warp the paper (tested many times with large dark areas on 80 g/m2 office paper). And one last caveat: if the printer sits idle for some time (several months is enough), ink in the jets may dry up and clog them.
- Pin (works like a typewriter, just with pins instead of types). If the printer is good enough (at least 180 DPI), it can work like charm for "white" models (intended for later manual painting), prototypes, drawings, templates and so on. The print is monochromatic and water-resistant; besides that, it has all properties of ink print. An advantage is its cheapness. A disadvantage is its unability to print textures or generally any large dark areas, because the pins terribly warp the paper. And, of course, the monochromaticity and quite low resolution. Also pay attention to aspect ratio, some printers can stretch the page by several milimeters in one direction.
Xero-copiers are actually just laser printers, but the print quality is not that good, so if you want, for example, to rescale a model, it's better to find a good scanner and printer.
Print quality depends on brand and type of the printer and paper, but also on the settings. Every printer has different possibilities, predefined options and profiles. It's always better to print a test page (or even something smaller) and fiddle with the settings until it looks good. For example, the usual choice "fast - normal - high quality". First option means unusably low quality, second one is usually a good choice and the third one is just more consumed ink and longer printing time without any perceptible improvement (at least on HP brand). Also, be careful about automatic colour enhancement, resizing or orientation - it is better to turn all these "useful" functions off than to end up with a twenty-page model having different scale and colours on every page.
How to set print scale?
It depends on file format of the kit:
If you want to print at the scale the kit is designed for, then it's easy: in the File - Print dialogue, turn off "fit to page" option and you're done (it's also a good idea to set page borders in such way that nothing gets cropped).
If you want to change the scale, it's sort of problem. Acrobat Reader normally can't do it (rumor has it that some newer versions can, but I've tried all from 4 to 9.4 and they can't). You can print multiple pages per sheet (inaccurate), create a custom page size as the desired percentage of A4 and then turn "fit to page" on (quite crazy, but might work), or you can install a virtual printer that turns the printed PDF into a bitmap and then continue as in point 2. Easier way is to download Foxit Reader, which can set the scale as you need - older versions (tested up to 3.0) only in certain predefined steps, newer ones should be able to set any percentage.
- Bitmap image (PNG, BMP, JPG etc.)
Rescaling is usually not a problem here (with an exception of integrated image viewers in Windows XP and newer, which usually can't set anything at all). Print size can usually be set either absolutely in centimeters or inches, or relatively in percents. But the percents can be used only if the computer knows what they are counted from. That's determined by an important number: resolution. It's expressed in DPI (Dots Per Inch) and it says how many pixels will fit into one inch (25,4 mm) on the paper. If this number is not set (GIF format doesn't support it at all, with other formats the authors sometimes forget to set it), relative size has nothing to catch on, so you have to specify size in length units. In some viewers (for example my favourite IrfanView) you can set the DPI as you want. Generally it can be any number - it is only a factor for recalculating pixels to inches, it has nothing in common with resolution of the printer (which is expressed in DPI as well).
- Vector drawing (DWG, DXF, SVG, CDR, PDO etc.)
Scale is usually no problem here, because the files use the target length units (milimeters, inches or the like) directly, instead of pixels. You usually need a special viewer or editor and it should have no problems with scale settings.
Some printers (I tested it with one HP and heard about some Canon, but don't know about other brands) let you set print scale in the print properties dialogue. That means you set 100% in the program from which you print and the final scale is adjusted in the printer.
How to calculate how many % do I need?
If you want to go from scale 1/A to scale 1/B, divide A by B, multiply the result by 100 and round it to the nearest whole number so the printer understands it. If you don't want to do the math manually, look at the Programs section and download the scale calculator.