Back in the early days I worked at a glass factory and the imprint size was around 2.75”tall x 7-8”wide depending on the item. THis was at the entry of the desk top graphics programs. Photoshop and Illustrator etc. Most smaller shops were using desk top printers such as a 300dpi toner printer. This is about the time of converting from Stat camera’s and shooting film positives filling areas with zipitone sheets of halftone dots that you would rub and transfer into areas as fills for various shades or “tonal fills”.
As we started into using graphics programs like Illustrator, Photosho, Corel and Aldus Freehand, the printer technology was not yet as advanced. Many were 300dpi printers and the quality of the line art and halftone dots (on paper) were not good.
As a work around, (for our shop) due to having a much smaller print area, (on glasses and coffee mugs), we could now create the art in the computer and do so much more with it. All art had to be created at double the size needed. A 2.75”x 3”wide area (for a one sided print) would be created at 2 times that size. Then once you printed the separations onto paper, you could send it back to photography and have it reduced 50%.
This Photo reduction also provided a clean up process of the halftone tones. When printing on the paper, the paper is very fiborous and you could see bleeds and spreads that added to the poor qualit yof the 300dpi output. With the camera, this was able to be burned out (literally). Any of the non solid spreading areas would be harder to capture thus burning out during exposure. This cleaned up the dots.