This instructable is designed to give users tips on how to achieve best color results when designing models to print on the Davinci Color 3D Printer by XYZPrinting.
Step 1: About the Printer
The PLA Filament for the Davinci Color is a speciality blend designed specifically for the absorption of droplets of ink, which is what makes the da Vinci Color able to print full-color prints. It is a semi translucent filament that once printed is a cloudy white. 3rd party filaments are not compatible with the 3d printer and the colorization process.
The Printing Process
The Davinci Color 3d Printer uses 4-color (CMYK) inkjets during the coloring process. The printer deposits ink on the outer shells of the print which helps to conserve ink.
Step 2: RGB or CMKY Image Map
Though you can design a colormap in RGB, you can sometimes achieve better results by using CMYK image files. Using a CMYK color map over a RGB can result in darker and more vibrant colors. Where as using a RGB color map allows the printer do the color conversion for you and some colors can become lighter than intend.
Step 3: Use Web Safe Colors
Web Safe Colors are an informal standard of 216 colors that are generally considered web safe. In the early days of personal computers, most displays only supported 256 colors. Out of these 256 colors, monitors/operating systems/browsers generally represented 216 colors in a relatively consistent manner. Hence, these 216 colors were deemed to be web safe.
It is not required to limit your color designs to use 216 color pallet, but some colors can be very hard to reproduce in CMYK. Safe Colors fall into a reduced color gamut that should be attainable with most typical color printers including the Davinci Color 3D printer.
Step 4: Use Contrasting Colors
Contrast plays an important role in the success of a color print. Colors that are too low in contrast or similar to surrounding colors can be hard to interpret and create by the printer.
While it may be easy to determine which colors do not work well together, it can actually be very challenging to decide what colors work well in contrast to others when designing color maps. One solution to tell if colors will print is to desaturate your color map in a image editor and add about 25% lightness (compensate for the translucent filament the 3d printer uses).
For example in the provided image a small amount of blue (cat eye in top colored map of the image) can be misinterpreted by the printer and not print properly when surrounded by a large amount of a grey that is of similar contrast. On the bottom part of the image the colored map for a character has contrasting colors and a higher success rate for printing colors correctly.
Photoshop or GIMP
Add a Hue and Saturation filter to your map. Change Saturation to -100 and lightness to +25.
Step 5: Create UVW Maps
UVW mapping is a mathematical technique used to "wrap" a 2D image texture onto a 3D mesh. "U" and "V" are the names of the axes of a plane, since "X", "Y" and "Z" are used for the coordinates in the 3D space. For the Davinci Color, the printer takes the design's UVW map and reads where to apply appropriate colors on the current layer.
A UV map is useful for determining resolution of details in a color map. For example if you want text to appear clean and printable on a small design you should give the area where the text lies more UV space (or its own color map). And on the alternative side smaller UV space can be granted to areas with less detail such as the eyes of the bear in the reference images.
You can use 3d softwares such as Blender (Free), MeshMixer 3+ (Free) ,3ds Max (Comercial), Maya(Comercial), Zbrush (commercial) and many more to create UVW maps.
Step 6: Bonus: Post Processing
To darken the color more, you can use a light lacquer such as the spray paint from a craft store or cheap clear coat nail polish (my preference). I don't recommend XTC-3D as it will make the colors run and look more faded.