Ep 3: The truth about printing...EXPOSED! PPI vs DPI vs LPI

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We Explain The Halftone Process, PPI, DPI and LPI. And we show you in detail how to create high quality images that will literally POP off the printed page.

Today we are going to reveal the TRUTH about printing. We are going to expose the fact that printing is really just an optical illusion. What we think are continuous tones and gradients are really just a bunch of tiny dots smoothed by the human eye into the beautiful full color images that we see in print. We explain how the relationship between pixels per inch (PPI), dots per inch (DPI) and lines per inch (LPI) is vital to creating the highest quality images. And we show you in detail how to create high quality images that will literally POP off the printed page.

We’re going to dive into this magical and mysterious process and explain how pixels and dots come together through the halftone process to make the magic of printing happen. And once this is revealed we are going to explain how you can use this knowledge to create photos and images that truly pop off the printed page.

Halftone Process

The halftone screening process was invented over 100 years ago. Although we have made incredible technological advances over that time we still use this basic principle in printing because our eyes and brains haven’t changed. We are still fooled into thinking tiny dots grouped together in a certain pattern form continuous tones.

Here’s a grayscale image that goes from black to white. It was created with a laser printer that only has one color black. Millions of black dots laid down individually trick our mind into thinking we are seeing hundreds of shades of grey.

The printing process is binary. Ink or no ink. The ink cartridge is doing one thing: printing a black dot.

As you can see in the enlarged image to create the shading, small dots placed next to each other in a certain pattern tricked the eye into thinking it is seeing many shades of grey. That’s the basics of halftone technology.

For color printing we just repeat the halftone process for each of the four colors Cyan, Magenta, Yellow and Black. The semi-opaque property of ink allows halftone dots of different colors to create another optical effect, full-color imagery.

CHECK OUT THIS BLOG POST where we outline in detail how the colors cyan, magenta, yellow and black printed at angles create the full color image. Here’s the link if you wanna check that out.

How The Dots Are Created Photographic Halftoning

Before Computers Halftones were made using cameras and screens by re-photographing the original photo through glass with a pattern of tiny screens, onto film which was then exposed onto a metal plate.

Digital Halftoning

Now with computers we use software, lasers and Raster Image Processing (RIP) to create the dots. Digital halftoning has replaced photographic halftoning since the 1970s when “electronic dot generators” were developed. These calculations are made by the RIP. The RIP converts pixels into dots. The RIP will calculate...