Tuesday, 15 April 2014

What is ...a Crow's foot?

What is ...Number 4
Regular followers of this blog will know that in the middle of the month, I publish a "What is ....? post. The article covers various aspects of paper, printing and finishing in greater depth. However, many of these subjects are complex, so these posts are only intended to be a brief introduction to the topic.
What is ...a crow's foot (in printing)?

Crow's feet
When the term "crow's foot" is thrown into a print related conversation, it leaves many who haven't been immersed in printing terminology baffled. Most people have heard of the term "crow's feet" applying to those narrow lines around the outside corners of your eyes which becomes more prominent as you grow older (don't worry, I haven't started writing a beauty hints blog!)

In the world of print and print finishing, the term "Crow's foot" refers to the creasing that you can get on a folded sheet which looks rather ugly, as the picture below: 
showing detail

A real crow's foot
Needless to say, the term is derived from the shape and pattern of a Crow's foot, a Crow, unlike some other birds, having a three toes. The problem of this ugly creasing appears to be caused by two factors which can either happen individually or in tandem. Firstly, there is the distortion caused by folding paper on itself and on itself again and again etc. The problem is that paper roughly doubles in size with each fold and this makes it harder to bend and results in the distortion (creases) on the inside sheets.
This effect happens whether paper is folded by hand or by machine. The second factor that causes or more particularly accentuates the "rippling" generally making more creases is mechanical folding. The increase in the creases is caused by air escaping, as it has nowhere to go (-readers familiar with printed sections being folded for binding will know that a rough perforation is made along the fold to allow the air to escape).
So, as you can see, this is clearly a problem - although it is one of those issues which generally rears it's ugly head when you are least expecting it! Many people think by using a lightweight material, such as our Offenbach Bible in 40, 50, 60gsm it will solve the problem - sadly the lighter weight material won't solve the problem on it's own!
How to get round it? - if producing an item which requires folding down, the best thing is to concertina one way and then concertina the other way. This means that the paper is never folded on itself and on itself again. It reduces the stress, prevents distortion and means that you never see a crow's foot! There are many examples of this already on the blog, here's a couple of perfect examples by NB:Studio and Studio8: http://justinsamazingworldatfennerpaper.blogspot.co.uk/2010/09/d-new-blood-2010.html, http://justinsamazingworldatfennerpaper.blogspot.co.uk/2009/07/shop-london.html
However, I can also show you a perfect example of just how not to do it! This folded down poster is a project for D&AD. Unfortunately there is no design or printer credit, so I can't reveal who was responsible, but it's the perfect example of a great idea but executed with lack of thought and poor production!
A5, portrait in size, reveals this amazing spectacle on the first spread...
close up detail
I'm sure that because of the quantity that would have been printed, the likelihood is that it would have been machine folded as this looks like the creasing that happens when air is trapped. The point is that it could still be machine folded but in a concertina which would have prevented this unsightly effect:
The whole poster:
...as many of my school teachers would have said about me ..."could have done better"!

Posted by Justin Hobson 15.04.2014

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Thanks for your comment! If I like it, I'll add it on. Cheers J