Digital DVD Printing
This method of DVD printing utilises pre-manufactured printable DVDRs. The discs will either have a white or a silver printable surface which is receptive to an inkjet printer. Printable DVDRs are widely available in high street stores or online and even high quality discs are inexpensive.
A Digital DVD printer works on the same principle as a desktop inkjet printer. The cyan, magenta, yellow and black ink cartridges are loaded into the printer and a printer head makes a series of passes over the printable disc surface depositing the ink according to the artwork file. It is possible to print extremely detailed high resolution images using this printing method but it does have a couple of drawbacks:
- The digital DVD printing process is slow compared to other printing processes – Commercial digital DVD printers are only capable of printing up to 200 DVDs unattended and each print can take up to a minute depending upon the complexity of the artwork.
- Each disc needs to be finished with a layer of clear lacquer – this is to protect the printed surface from potential moisture damage when handled. This adds more delay to the process.
However, this DVD printing process does not have any fixed set up cost which makes it ideal for short runs of less than 100 DVDs which is a service that is very much in demand with the advance of the digital download.
DVD Screen Printing
Screen printing is a tried and tested printing method that has been used in the commercial printing industry for decades. DVD screen printing is an adaptation of this process, modified to allow printing onto a disc. This process is great for printing areas of solid colour using vibrantly coloured inks mixed from various proportions of base cyan, magenta, yellow and black ink. There are also fluorescent and metallic inks available for use with this process.
A screen printing machine has a large rotating platform. The platform is split into 5 printing stations with a UV lamp between each station and the next. DVDs with a base coat of any colour can be printed on, which allows for a maximum of 6 different colours in the artwork design.
The printing screen, from which the process gets its name, is a very fine mesh screen which is initially covered with a thermally reactive emulsion. A separate screen is required for each of the colours featured in the final artwork and a celluloid film is also made for each colour. The film is black in the areas where the colour is required on the disc, and clear where it is not required. The film is attached on top of a screen and placed into an exposure unit. A hot, bright light is then briefly switched on over the top of the film. Where the light and heat go through the clear portions of the film to the screen beneath, the thermal emulsion on the screen is hardened. Where the film is black, the heat and light do not pass through the film and so the emulsion remains unchanged.
The screen is then transferred to a spray booth where it is sprayed with a fine water jet. The water washes away the emulsion which has not hardened leaving a screen where ink can pass through the mesh only in certain areas where that colour is required according to the design. The screen is then fitted to its station on the DVD screen printing machine. The other 4 screens are prepared in the same way and the machine is then ready to print.
The DVDs are loaded onto the printing machine automatically. They are presented on spindles and each disc is lifted by a robotic arm with soft rubber vacuum cups. The DVD is placed into a metal jig which holds the disc securely to prevent any movement whilst it is being printed. The metal jigs are lined up around the machine and the DVDs are loaded, printed and then removed once printing is complete. A DVD that has been printed and then removed is replaced at the next machine rotation with a fresh unprinted disc. This process continues until the production run is complete.
At each station a different coloured ink is applied to the disc when a rubber squeegee blade passes over the screen. The screen is pressed down onto the disc surface and the ink is forced through the mesh by the blade. Once the ink has been applied the blade returns to its starting position ready for the next disc. The machine platen rotates one position and the freshly printed disc passes under a UV lamp. The UV light from the lamp cures the ink instantly and the disc moves to the next station where the next coloured ink can be applied without any possibility of smearing of the previously applied ink. The printing and curing process is very fast and a modern DVD screen printer is capable of printing more than 3,500 DVDs in an hour.
The requirement for screens and films for each different ink colour in the design to be printed onto the DVD, means that there are fixed costs associated with this process. These costs can be minimised by limiting the number of colours involved in the DVD print design. It is perfectly possible to design an attractive disc using just a single colour print onto a printable silver DVD. The fixed cost, however, does make it a less viable process for very small orders of less than 100 DVDs.
Lithographic DVD Printing (Offset printing)
This process, as with DVD screen printing, is a popular printing method for producing high resolution images on paper or card stock and has been adapted to suit DVDs. Lithographic printing is the best process for producing DVDs with a photographic print or artwork involving a subtle colour gradient but is not great for printing artwork that has large areas of solid colour due to potential coverage issues which may result in a “patchy” print.
The lithographic DVD printing process involves making a metal printing plate which is curved around a roller. The basic principle at work with this process is that printing ink and water do not mix. The printing plate surface is treated in some areas so that it attracts ink, the remaining areas are treated to attract water and not ink. The result is a printing plate that can be introduced to ink which only adheres to it where required. The ink on the printing plate is transferred or “offset” to another roller which has a rubber blanket wrapped around it. The rubber blanket roller applies the ink to the DVD which is held firmly in place in a metal jig on the machine bed.
This process is equally as fast as the screen printing process and so many thousands of DVDs can be printed every hour that the machine is running. Once again, there are fixed set up costs involved here and so the cost to print orders of less than 100 DVDs is high.
DVD Printing Process Summary
In a nutshell, if your project is only for a small run of discs then digital DVD printing is the way to go. There is certainly no print quality compromise with digital printing over the other 2 processes and even though it is the slowest process, this is not really relevant if you’re only having 50 discs printed. There are many companies specialising in 24 to 48 hour turnarounds on short runs of discs who use this printing method exclusively and have it down to a fine art.
For projects where the amount of discs required is more than 100 and the artwork features bold, solid colours, then the DVD printing process of choice has to be screen printing. The metallic and fluorescent inks available for this process make for some truly eye-catching and distinctive designs. If the artwork for the discs is a photographic image or contains a subtle colour gradient, then the printing process best suited to this type of artwork would be Lithographic printing. For screen and lithographic printing, the more units ordered, the cheaper the unit cost becomes.