The-Golden-Image-Ratio

The Golden Image Ratio of Image to Screen Size

Winner of the prestigious 2016 Swormstedt Award and 2016 Best of Class Award for excellence in technical writing presented by the Academy of Screen and Digital Printing Technologies (ASDPT) of the Specialty Graphic Imaging Association (SGIA).

A good portion of the problems of those long and tedious registration times, where you settle for something less than perfect, the images that are distorted and with uneven and inconsistent color integrity are easily resolved.

It has long been understood that every screen has a printable image area, often referred to as the “sweet spot” in which the image must be placed. If the printable image area is exceeded the printed image will suffer in a variety of ways. The most pronounced problems will be with the ink deposit and registration – as they will not be consistent from the center to the edges of the image.

There are a number of theories about how to evaluate the printable image area. All of which propose that the printable image area is rectangular or square in shape, however, the printable area is actually an oval when using a rectangular frame or a circle in the instance of a square frame. This is due to the tension of the mesh which is concentric from the center of the frame outward.

The purpose of this work is to eliminate the confusion by providing a mathematical reference that offers a visual guide as to the proper image to screen size ratio.

The discovery of the Golden Image Ratio came about from mapping the known variables that exist within the screenprinting process with regards to the consistency from image edge to edge in relation to the registration, and the consistency of the ink deposit. While problems with both of these variables can be worsened or lessened with tension, off contact and squeegee size, they all depend on an image size that does not exceed the correct image to screen size ratio.

The Golden Image Ratio is proportional to the Standard Operating Procedures in place within a given shop, dependent upon the required tension levels, off contact distance dependent upon the rheology of the ink, and the degree of registration required.

The screenprinting technologies have struggled with problems arising from the printing of images too large for the chosen frame size, simply because there is no given rule of the image to frame size to follow. The image to frame size has always been one of the suggestions that vary widely.

With over 500 known variables within the screenprinting process, there is no need to add to the myriad problems already in existence. It is obvious that the screenprinting technologies needs a guide which can be adhered to by the frame and equipment manufacturers, as well as the screenprinter. With a rule in place to know the maximum image size of a given inside dimension of the frame, the confusion and often the ultimate failure of the printed image would not be the problem that it is today.