Physical and aesthetic properties of Graphic materials Technical aspects of designing and making Physical and aesthetic properties of Graphic materials

Aim of the lesson To understand about the properties of materials- hardness, toughness, strength, flexibility, impact resistance, strength to weight ratio and aesthetic qualities • Recognise the importance of understanding the physical and aesthetic properties of graphics materials when selecting a material for a specific use. The purpose of self and applied finishes protecting, preserving and/or enhancing the appearance of products, including laminating, varnish, UV lacquer, embossing and foil application

PROPERTY DESCRIPTION EXAMPLE HARDNESS the ability of a material to resist pressure, not easily scratched or dented acrylic sheet is considered hard and foam board is relatively soft TOUGHNESS the ability of a material to absorb energy on impact and change shape without snapping self adhesive vinyl is tougher than acrylic sheet STRENGTH the ability of a material to withstand forces without breaking, this can be pulling, squashing or bending FLEXIBILITY the ability of a material to bend without breaking plastic ruler are quite flexible, they bend quite a bot before they break IMPACT RESISTANCE the ability to withstand a sudden force without breaking STRENGTH TO WEIGHT RATIO materials that are strong but don't weigh much have a good strength to weight ratio important for spacecrafts and racing cars AESTHETIC QUALITIES the appearance of the material, three areas to consider are colour, texture and surface finish

Quick Questions 1. Describe what is meant by the following properties: tough opaque flexible 2. Suggest a product that needs to have: good impact resistance have a high strength to weight ratio 3. Suggest a graphic product for which strength is important and say why. 4. A student is designing a kite that will be made by covering a frame. He is deciding whether to make the covering from paper, plastic or fabric. a. what physical properties does the covering material need to have b. he thinks that the aesthetic properties of the material used for the frame are not very important. Is he right and why? 5. What physical properties does a material need to have to be used to make a bag to carry shopping?

Answers 1. Describe what is meant by the following properties: tough – can absorb impact without snapping opaque – light can't travel through it, its not see through flexible – can bend without breaking 2. Suggest a product that needs to have: good impact resistance – an aeroplane window have a high strength to weight ratio – a spacecraft 3. suggest a graphic product for which strength is important and say why. -protective packaging needs to resist squashing forces to keep its contents safe 4. A student is designing a kite that will be made by covering a frame. He is deciding whether to make the covering from paper, plastic or fabric. a. what physical properties does the covering material need to have – strong, flexible b. he thinks that the aesthetic properties of the material used for the frame are not very important. Is he right and why? - yes, the frame will be covered by another material and won't be seen 5. What physical properties does a material need to have to be used to make a bag to carry shopping? - strength, flexibiltity, strength to weight ratio, protective

SURFACE FINISHES

LAMINATING This also produces a high gloss finish on card and provides good protection against damage as it is normally water proof. The printed card is placed inside a plastic film/sleeve. It is then placed in the ‘in tray’ of a laminating machine which pulls the card and film through its heater and rollers. The heater warms up the film almost to melting point and the rollers press the film sleeve until it is sealed. When the card reappears in the ‘out tray’, the finished item looks glossy and professional. However, laminating is much more expensive than varnishing but gives more protection to the card. Adds gloss; Provides strength; Makes the document waterproof; tear-proof; and tamper-proof

EMBOSSING Embossing is the process of creating a three dimensional design/image on paper or card. Dies are used to squeeze the fibres of the material and raise the image. Can be used with ink – called colour register embossing or without ink – called blind embossing.

VARNISHING Fine varnish can be sprayed on to the surface of card. When dry this gives a gloss finish and helps protect the printing underneath. The printing and colour work must be completed before this process takes place. Also, folding a package takes place after the varnish has been applied. Different types of varnish are available. The most popular are oil and water based varnishes. In either case, the varnish takes at least two hours to dry. This may be a disadvantage, especially if the card is being used for a package as it means it can not be folded straight away. Produces a gloss or a matt finish Speeds up the drying process Locks in the ink under a protective coat to prevent the ink rubbing off

UV VARNISHING ULTRA VIOLET VARNISHES Special varnishes dry almost straight away if they are exposed to ultra violet light. (UV light). The varnish is sprayed on to the paper / card in the same way as other varnishes. However, after spraying the card passes underneath UV lights which dries the varnish almost instantaneously. One disadvantage is that this type of machinery is expensive to purchase. However, it produces an excellent gloss finish to the card / paper.

FOIL APPLICATION Means using heat and pressure to print metal foil onto certain areas of a product Often used to produce silver or gold letters on cards. Expensive The foil comes on a roll that when sandwiched between the item being printed and the plate it releases the foil in the areas that the plate touches.

Quick Questions 2 1. A colour leaflet promoting the Valley Leisure Centre is to be distributed in the local area. The leaflet is to have a gloss surface finish to the paper. a. Name two effects that could be used to give a gloss finish b. Explain two reasons why a gloss finish to the paper may be needed. 2. A printed brochure advertising a local company is to be produced. It must have a high quality appearance. Name one effect which may give this appearance and describe how it is achieved. 3. Name the industrial machine used to cut and shape batches of card with straight edges.

Answers 1. a laminating and varnishing 1. b high quality finish, visual impact, improved durability, menu will be handles by a lot of people 2. laminating / varnishing / embossing 3. guillotine / rotary trimmer

DIE CUTTING Die cutting or stamping is the process of cutting and creasing sheets of material. The die cutters are like pastry cutters mounted in a press which are then forced down onto a material. The main processes are: Cutting – separating the material completely Creasing – making an indentation that will allow the material to fold Hole punching – making a window or an opening Die cutting is a fast and efficient process, replicating the same shape over and over again. Paper card and sheet plastic can all be die cut.

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