by Ray Robinson

A Decal is a thin clear plastic film, with water soluble glue on the back, so that it can be stuck to surfaces. It is available on A4 paper suitable for a printer. Most Decals can be made using normal black ink with a normal printer. On occasion, there is a requirement for other colours, particularly the colour white. This is possible.

There are 2 popular models that deal with colour, additive and subtractive mixing. The additive model works with emitting light sources, commonly used in colour TV tubes and computer monitors. The 3 primary colours, RGB (red, green, blue) are mixed in varying quantities, and create all colours except black. White is when all colours are ON. Black is when all colours are OFF, however, it is really the unexcited natural colour of the tube or screen, which passes for black.

Figure 1: RGB Mixing.

The subtractive colour model relies on light being absorbed, being commonly used in inks and printing. There are 3 primary colours CMY (cyan, magenta, yellow) that when mixed in varying quantities, create all colours except white. Black is when all colours are ON, although this can commonly be a brown colour. White is when all colours are OFF, and you then rely on the background medium, this often being white paper.

Figure 2: CMY Mixing

Colour printers usually have 4 colour cartridges, the addition being Black, as the colour cartridges are expensive, and instead of using 3 colours to create black printing, only one need be used.

It is difficult to make white with these inks. However, there are special printers manufactured for the printing industry, that actually contain a separate White ink cartridge, but these are for business, have a small market, and are expensive. There was a low cost printer made by ALPS Electric Co. of Japan, which was aimed at small business and hobby users. This was not a Laser or Inkjet or ribbon method. It used a thermal technique to transfer wax ink to the paper or material. It was called MicroDry and was also licensed to the OKI (DP series) and to Citizen (Printiva series). There was also a Tectronix Phaser series that used thermal wax ink.

The ALPS, OKI, and Printiva all use the same ink cartridge. The cartridge is similar to an audio cassette tape, in that it contains a tape that moves between 2 enclosed wheels. There are several cartridges, Black, Cyan, Magenta, Yellow, White, Metalic Silver, and Metalic Gold. The printers were also designed to print photographs, so they had additional cartridges, Photo Cyan, Photo Magenta, Photo Yellow, and Clear Finish. The photo cartridge body is made of blue plastic, whereas the others are a grey plastic, so that they can easily be distinguished. They also have a coding on them, so that the printer can determine which ones are fitted.

The printer I used is an ALPS MD-1300 colour printer. This printer has storage for 4 cartridges in the opening lid, and uses each one in turn, so the printer is slow. The normal fitting is Black, Cyan, Magenta, and Yellow, and the printer driver will complain, if these are not fitted. The ALPS printers use a parallel printer port so they are unsuitable for modern computers that only have USB ports. I have tried a USB to parallel adapter, but these usually pass data only one way, so there is no printer feedback to the computer. There are several printers in the ALPS range, and I purchased mine, second hand from the on-line auction site. ALPS is now out of business, as colour inkjet and colour laser printers are so cheap .You can still purchase new ALPS cartridges. There is an ALPS printer group on Yahoo groups, and there is plenty of information in the group archives. The printer driver is also here.

The normal paper is available from several suppliers. The supplier I used is BEL INC. 10319 N.W. 30 Street, Suite 103, Miami, FL 33172, USA. This is a clear Decal film on a white paper backing. They also supply the same decal paper but with a blue backing, so that white ink can be seen. I used the normal paper, for laser printers.

Use your favourite graphics program to create the artwork for your Decal. I use Microsoft Paint, or sometimes Word, or sometimes Corel Draw, or sometimes Open Office. For single colour printing, make the artwork as normal black lines on a white background. When you make test prints, you will be able to print them on a normal printer. When the artwork is complete, save it. I then load it into Microsoft Word, and this allows me to grab the edge of the artwork and make it bigger or smaller, so that the printed size is correct. Word has a ruler along the top, so that you scale it easily. If creating a complicated artwork with text on a radius, as for dials, I use Corel Draw. If it is simple straight line text, I will use a simple drawing package. In this case, I wanted to copy a dial marking scale. I scanned it first, then edited the image with Microsoft Paint. I converted it to monochrome, then edited each individual pixel, until the dial markings were cleaned up.

Figure 3: original scan

Figure 4: partially edited

Figure 5: Finished artwork

I printed the artwork on a normal printer, to check for mistakes, and to scale the size properly. Once it was correct, it was time to print it on the colour printer. I set the printer up, so that it would print, substituting white ink where it should have used black ink, using the “spot” function.

Spot printing allows you to override the correct colours and select your own. Go to the “Printers and Faxes” menu, and right click the ALPS MD-1300 Icon, which will activate a drop down menu. Left click the “Printing Preferences” entry. This will launch a new window, that will allow you to configure the printer colours. The “Document/Quality” tab, has a “Print Mode” field, at the bottom left hand side. This should be set to “Standard Color” otherwise, the printer will think it is printing photographs, and will want a different set of colour cartridges. Just above this is a check box, labelled “Use Spot Color(s)”. Click this. It launches a new menu, to allow you to select the colour. Choose “Single Ink” and also choose “White”. Press OK. Again press OK. Now, anything you send the printer, will be printed with White ink. Print from your application, in my case, this is Microsoft Word. Set the configuration back to normal when finished (uncheck “Use Spot Color(s)”, and select “Standard Color”, press OK).

Figure 6: Image on screen, and printer open, showing cartridges.

For a modest outlay, white decals can be printed. The process needs an older computer with a parallel port and an out of production printer. These are still available, but their life expectancy is unknown. It is unfortunate that this technology has been bypassed.

Figure 7: C17020 receiver using white decal

I used an ALPS MD-1300 printer, using a parallel port. The computer was a 5 year old Intel based PC. It was running Microsoft XP, Service Pak 3. The printer driver was Alps version 2.2.2 W2K-XP. The supplied Setup installed the program correctly. I used Microsoft Paint and Word.

Ray Robinson VK2NO

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