There are several types of printing methods in the graphic arts sector. Each of them consists of three processes: pre-press, printing and post-press.
To get a high-quality product not only the printing needs to be taken care over but also the arrangements and the finish of the printing need to be kept in mind.
2.1. Most popular printing finishes for large format
1.Printing processes in graphic arts
With the aim of having a better context of the types of special finishes that the industry offers, it is necessary to deal with the differences among every printing process.
The description of each stage that is made further on is of a general nature, in order to avoid expanding on every type of printing system.
However, we will give special importance to digital printing and we will handle the last process more in depth: post-press, most commonly known as finish.
1.1.Pre-press
It is the stage that precedes the printing, the process where the job is optimised. Tasks such as scanning, colour test, image setting, etc.
Regarding digital pre-press, the tasks are specialised in image digitising, text processing, digitising of the originals if needed, page layout, assembly of digital publishing, typesetting, etc.
All in all, this stage is for optimising and preparing the printing, keeping resolutions, dimensions, format, content and media in mind.
1.2.Printing
Among the most common printing systems there is: offset printing, gravure printing in rotary presses, flexographic printing in rotary presses, screen printing and digital printing.
The equipment, techniques and media are different for each system. Digital printing differs from other techniques mainly because it does not use a matrix to do the printing job.
In this sense, its low cost and printing speed are their main advantages. There are different technologies which embrace digital printing and each of those techniques is different according to the format that is used.
The versatility of the digital printing allows to print on different media such as paper, canvas, banners or vinyl.
As regards banner printing there are three main materials: frontlit banner, PVC mesh -also known as mesh fabric-, blockout banner and backlight banner.
1.3.Post-press
The finish plays a practical, functional and quality role in the printing processes.
Once the printing is done, the material must be punched, folded and varnished to be ready for installation.
For example, when printing documents like books, it is meant by 'post-press finish' the binding, sewing, ring-placing, creasing, punching or half-cut.
It is meant by special finishes in graphic arts on paper the following types of finishes: lamination, encapsulation, varnish, stamping, false relief, embossing, safety ink, etc.
As regards sign digital printing on banners, the finishes are related to the way that the banner will be exhibited.
In any event, with the aim of obtaining an excellent finish it is necessary to take three factors into account: the quality of the support, the perimeter reinforcing webbing and the right choice of eyelet type.
2.Printing finishes for large format
In the visual communication sector, large format printing of posters and advertisements is a very common technique which offers great results in terms of printed advertising media.
They are used for shops, malls, fairs, shows, festivals and events in general. The most common supports that the industry uses are vinyl, banners, flags, advertising display boards and large format paper.
It is important to assess the type of support and technology to be used, according to the production volume and keeping in mind if the part is displayed outdoor or indoor.
2.1.Most popular printing finishes for large format
Bleed trimming
Once the banner is printed, it is necessary to cut it to get the chosen dimensions. It is commonly used in fairs and shows, being the most basic way of finishing the banner.
Banner edge reinforcement
This system is recommended to add the maximum resistance against tear. The edge is reinforced whether by folding the banner itself or by using webbing along the edge, which allows to increase the thickness of the banner where the fastening system will be set, that is, the eyelet. With the aim of adding this load webbing it is necessary to weld with high frequency techniques, hot air, hot air wedge or ultrasound techniques.
This system is needed for all kinds of fastening; however, for very small banners that will only be used during one or two days and which will not be exposed to the inclemency of the weather this option could be omitted.
Hems
Also known as trim, they are an alternative to eyelets. It is often used on lamp post banners or indoor spaces. This reinforcement is obtained folding the material of the banner with the purpose of sewing or welding it. Once the fold is done, a pole is placed into it in order to hold the banner.
For indoor spaces maybe one single pole is needed on the upper part, whereas for outdoor spaces it is recommended to use another lower hem to increase the tightness.
One of the disadvantages of this system is that if the sewing technique is used, the material suffers significantly as it is constantly punched; so the resistance to the pull tension is affected. At a visual level, sewing makes the aesthetics of the banner poor, remaining quite visible on the image.
Banner hanging with eyelets
Setting eyelets allows hanging the banner properly. Eyelets are necessary to protect the banner from the tension that is exerted between the media and the frame.
Without this piece, the banner would break easily. The choice of the eyelet will depend on the type of banner and finish. To set the eyelets, it is necessary to use specific machines that punch and set the piece.
Hoop & Loop and tapes
They are another kind of reinforcement for the perimeter of a banner. Double sided tape could be used for sticking the material together on the front and back of it.
They are recommended for print shops which do not have any welding equipment or for applications such as banner stands. Sometimes adhesive hoop & loop is used as it is the case of pop-up or display banners.
Refuerzo de lona adhesivo.(Ref. PSRFA40)
The graphic arts sector includes a complete system of solutions for visual communication. It is an industry that is undergoing constant changes which depend on the technology of the moment.
Becoming familiar with the different processes allows us to have an overall view of the graphic arts and large format signage.
At PLASTGrommet we are manufacturers specialised in finishing solutions for digital printing, from commitment to quality.
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