All About Print: Part 1.

All about print is a series of educational articles focused on the world of ink and paper, something we’re hugely passionate about here at Left Bank Gallery. Every fortnight, we present a new topic full of helpful information with the aim of helping our clients better understand the vast industry that is printing.

To start the series off, we’ll begin with an overview of the topics we will cover in the coming weeks.


Colour

Colour is by far the most difficult aspect of printing. Not only do different devices, like scanners and cameras, capture colours differently, but every screen/monitor will display colour differently. Monitors will display colour differently depending on the ambient light, so the type of light in the room, and the way it reflects off the walls, can influence what colour is shown. And if that’s not enough, every printer will interpret colour slightly (and sometimes significantly) different to the next.

Let’s not forget that colour is perceptual too! The lovely lime green I see may look more dull and olive like to you.

Another consideration when talking about colour in printing, is the colour ‘mode’. You may have heard the terms ‘RGB’ and ‘CMYK’ thrown around before. These are colour modes - RGB stands for Red, Green and Blue - the colours that are used to display digital images on screens including your television, your computer monitor, and your phone. RGB is not used for printing.

  The RGB and CMYK colour modes. Notice how when two colours overlap, it creates a colour from the opposite mode i.e. Blue and Red in RGB overlap to make Magenta - however it is a vivid magenta, whereas the CMYK Magenta is less vibrant.

The RGB and CMYK colour modes. Notice how when two colours overlap, it creates a colour from the opposite mode i.e. Blue and Red in RGB overlap to make Magenta - however it is a vivid magenta, whereas the CMYK Magenta is less vibrant.

CMYK stands for Cyan, Magenta, Yellow and Black (K so as to not be confused with Blue, or because it is the ‘Key’ colour). CMYK is the colour mode used for most printing we see today. The four colours mix together to create millions of printed colours.

We’ll cover the nuances of colour management and colour modes in more depth when we dedicate a whole topic to it in a few weeks time.


File Types

With the proliferation of the internet and personal computers in the past decade and a bit, almost everyone has access to tools to create designs or artwork. However, most consumer program suites don’t create the correct file types necessary for high quality reproduction on a printing press.

  PDF files are great for printing.

PDF files are great for printing.

The most common filetype in today’s digital world would have to be the JPEG (Jay-Peg) or JPG. This file format is used primarily for photos as it has a great knack of compressing the files size so it is easily downloaded and viewed. The fact that it is a compressed file makes it not ideal for printing.

Another common format is the PDF. This generally is the preferred format for printing in, as the PDF, when saved correctly, does not compress files like a JPG does.

TIFF files are another format great for printing, as they are a ‘lossless’ file type that allows for high quality files to be saved time and time again, without any compression. These are superior to JPGs, but they are generally large files so are quite often hard to send and download.

Vector files are created in professional design programs, and they are a completely lossless file type that can be scaled to any size without loss of quality. For example, vectors are ideal for logos so they can be scaled up and down with ease. Vector files are quite often saved from Adobe Illustrator in the native AI format, but can also be saved as EPS files too.

Bitmap and GIF files are low quality files used on the internet and are therefore not suitable to print from.

There will be a more in depth breakdown of file types in a few weeks time.


Image Resolution

When talking about a ‘raster’ image - which is an image made up of pixels (any photo you take on a camera, or image captured by a scanner) - the main concern is the resolution of the image. Resolution is measured by how many pixels per inch (PPI) the image contains. You may have heard the terms 72dpi or 300dpi before. DPI actually stands for dots per inch and is meant to describe the number of dots a printer is capable of putting down onto the paper, not how many pixels are in an image. However, it has become the common way of describing resolution instead of PPI. We’ll stick with the correct terminology!

  An example of how pixels per inch work and how it effects how an image displays.

An example of how pixels per inch work and how it effects how an image displays.

72ppi images are suitable for on-screen display, as they are generally lower quality because they contain fewer pixels. However, a lot of digital cameras capture images at 72ppi, even when they are set to their highest quality. This is because the actual file itself is about 1000 x 700mm in size, so it is a huge physical image, but doesn’t have many pixels per inch at this size. A simple conversion in Photoshop to 300ppi makes the image 240mm x 168mm. This is the true, high resolution ‘printable’ size of the image.

We’ll divulge more information on Image Resolution in the coming weeks.


Printing Methods

There are many different ways of getting ink on paper, and we humans have been doing it for thousands of years. Without getting too much into the history of printing, and every printing method available, there really are a two mainstream methods used today.

  A cross-section type look at how an offset press works.

A cross-section type look at how an offset press works.

Offset printing, also known as Offset Lithography or Litho Printing, is the most common way to print items such as business cards, letterheads, newsletters, postcards and flyers. It is cost effective on medium and long runs and is a high quality, versatile method of printing. The concept behind offset printing is that oil and water don’t mix, so the image area of a printing ‘plate’ attracts the oil in the ink, whilst the non-image area is wet, and repels the oil-based inks. This plate is then pressed onto the surface of the substrate.

Digital printing has emerged in the last 20 or so years as the newer, more popular way to print. Digital printing is produced on either a inkjet or laser printer, where the image to be printed is sent directly to the printer via a digital file (like a PDF). This eliminates the need for a plate, so the cost savings are huge for smaller runs. Digital printing can be expensive once larger runs are needed, as the costs are fairly fixed, unlike offset printing which has large setup costs, but minimal costs once it is underway.

Other methods of printing like Screen Printing, Flexography, Pad Printing, Letterpress Printing and more will be discussed in a few weeks time.

In conclusion to today’s post, we’ve just scratched the surface on a few of the major topics to do with printing. Over the next couple of months, we’ll release a dedicated post on each of the points covered today, with more detailed information. The design and print team at Left Bank Gallery - myself (Toby), Michelle and Julia, are well experienced in all things print. I’ve worked as a print designer for 12 years now, and have been running small and large format printing machines here in our Southport workshop for around 6 years. Contact us today to discuss how to setup your files for printing or for any general design and print advice.