Litho vs Digital – which is better?

June 22, 2011

in Print work

There’s only one way to find out….FIGHT!

We’re often asked why we choose some jobs to print digital and others offset litho.   Up to five years ago, the choice was easy…if quality wasn’t an issue and cost was, then print digital, otherwise always print litho.  Nowadays, with the advancement of digital presses, the choice is not quite as clear cut.

So let’s look at the two main technical differences between either process….

With litho, we have to make one metal plate per printed colour and the plate and press set up (or make-ready) costs are fixed.  With digital print, no plates are required and the set up costs are relatively small. 

The ink transfer between the plate and the substrate (paper) with litho is a chemical transfer, with the oil-based inks adhering to the plate, transferring to a rubber blanket and then passed onto the surface of the substrate.  With digital presses, we use toner (either liquid or powder) and the toner transfer to the surface of the paper is created by electro-statically charging the toner particles.

With the basic differences in mind, let’s now look at the criteria we use when choosing a suitable process for your work.

Criteria 1 – job quantity.

The difference in the fixed costs between either process means that digital tends to be more cost-effective for running smaller quantities; as the cost per printed sheet (click charge) remains constant then after a certain volume, litho printing becomes more cost-effective.  As a rule of thumb, we think that any quantity equivalent to and less than 500 x printed A4’s (eg 250 x A3’s, 1000 x A5’s etc) will be competitively priced if printed digital.

Criteria 2 – substrate.

There are greater restrictions on the weights of paper that can be run through a digital press.  On the HP Indigo digital press, for instance, we would only recommend printing papers between 100gsm and 350gsm.  The surface of the paper must be receptive to the toners and in some cases will have to be pre-treated with a special treatment called ‘sapphire coating’.  In our experience, textured stocks can also cause technical issues.

Criteria 3 – job size.

Litho presses come in a wide range of sizes and we are able to print any sheet size from  A4 up to Ultra Quad (which for the less ‘senior’ of you is around 150cms x 180cms).  The range of press sizes available with the digital press market is less expansive and where possible we try and run any job over A3 flat size on litho presses.

Criteria 4 – number of colours.

Digital printing really does only lend itself to printing in black or full colour.  It is possible to print in special colours on some digital presses but the cost of having the toner mixed to order is very expensive.  If your job has a special colour that does not print out of CMYK, then it would have to print litho.  It is not possible to print metallic colours on a digital press.

Criteria 5 – quality.

At the beginning of this post, we spoke about how the technological advances in digital presses means the much higher quality available.  Certainly, in some cases, we think the quality of digital print is superior to litho.  When printing on uncoated papers digital print tends to give a much sharper and brighter printed result over litho (we have discussed a job very well suited for digital printing on one of our earlier blogs)

‘Quality’ is the most subjective of the five criteria and we use our experience in looking at your design to see which process will give the best printed result. If you have questions on any print process or would like to attend one of our mini-inductions to print then please don’t hesitate to contact us through the general enquiry form on this site.

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