In DLP 3D-printing, each layer is built by projecting an image consisting of on- and off-pixels onto a photopolymer bed. In order to control the photopolymerization process and the quality of the print as accurately as possible, you’ll want to have a sharp image with a high contrast.
In optics, the ability of an optical system to faithfully transfer the contrast of an object onto the image plane is measured through the CTF value.
CTF stands for Contrast Transfer Function. The higher the CTF, the sharper the image.
When looking for a UV DLP projector for your 3D-printing system, you want to make sure that the CTF value is high enough to ensure the precision of your printer.
See a detailed definition of CTF and how it is calculated in our technical handout.