Why does the same color in a bitmap/raster file not turn out to be the same in a vector artwork file or vice versa?
As strange as it may seem, the same color (for example: R255 G0 B0, which is red) comes out a little bit different depending on what graphics program was used to create the digital artwork in, and/or was imported into.
Furthermore, it is possible that the raster/bitmap art file was create in the RGB color mode and the vector art file in the CMYK mode.
Based on these observations, a vector text for example, placed over a bitmap or raster image that both contain the same 2023 Nude Calendars red, for example,will print out slightly different red colors. This phenomenon is due to the different ways vector-based images and bitmap/raster-based images are prepared for printing by the various digital printing engines.
To overcome this “oddity” it is possible to create all text in the same raster/bitmap program that also created the image file. To assure that the text so created will not be reproduced in a pixelated manner, the resolution of the raster/bitmap file should be at least 300+ dpi’s. In the case of an artwork completely created in a vector program, there are no limitations as to colors nor resolutions, as all vector files are resolution independent.
Why are there differences in appearance from one mug decoration to another using the same digital art work file?
Sometimes there is a slight difference from one decoration on one mug to the same decoration on another mug using the very same digital artwork as their source. This is sometimes more noticeable with full-size raster/bitmap decorations containing continuous-tone images than with vector-based artwork.
These differences can be caused by many factors, as for example by:
the surface differences of the individual ceramic coffee mug itself;
the composition and quality of the mug coatings;
the chemical composition of the white glaze on the coffee mugs;
slight variations of size and circumference of the coffee mugs;
differences in the pigment inks used for the printing of the decorations;
the use of a given printer, as no printer prints the same;
color correction applications produce different outputs;
printer drivers for different operating system and printers generate different print images;
the quality and characteristics of the paper medium the decoration is printed upon.
Since we purchase all of the above (such as blank coffee mugs, pigment inks, paper media and printers) we have absolutely no influence over the final printed mug decoration and hence cannot guarantee the same identical mug decorations from one production run to the next.
Slight differences from one mug decoration to another are unavoidable especially for full-color reproductions of continuous tone images such as scanned photos and/or raster artworks with rather large dark areas. Even some banding has also to be accepted as normal for spot- and full-color mug decorations.