CMYK – Stands for the four colours used in “Full Colour Printing” (also called “Process Printing”). C=Cyan, M=Magenta, Y=Yellow, K=Black. All the colours seen in Full Colour printing are made up of different percentages of each of these four colours layed down as a pattern of fine dots on top of one another. If you look at magazine printing with a magnifying glass you can often see these dots of the four different colours.
RGB – Stands for Red, Green, Blue, and refers to the colours used on computer screens and other electronic devices. RGB provides a greater range of colours than CMYK, but it can’t be relied on for accuracy because colours change from monitor to monitor depending on the settings.
SPOT COLOUR – This is when inks are mixed up like poster paints are, using a range of base ink colours so that nearly any colour can be matched. The colours are mixed according to a guide containing hundreds of colours along with their percentages of the base inks. (One of the most common Spot Colour matching systems is the Pantone Matching System, or PMS.) The main draw back with Spot/PMS/Pantone colour is that jobs using it must be printed individually, so there are no price savings gained from printing many jobs together (Gang Printing).
As with RGB colours, Spot colours do not always translate accurately into CMYK. Graphic designers who do corporate branding will often specify which RGB, CMYK or Pantone colours are to be used for that client depending on where it is being used, e.g. RGB for online, CMYK for brochures, and PMS for Screen printing on a T-Shirt.
BLEED – Most printing is done on Stock (paper/card etc) larger than the finished size, and is then trimmed in a guillotine. Bleed is the term used for the artwork that extends beyond the finished/trimmed size. If artwork only goes to the edge of what will be the trimmed size, the printing could end up not going all the way to the edge of the product printed.
CROP MARKS – Also called Trim Lines. These are provided on artwork to show where the paper/card etc needs to be guillotined.
FILE FORMATS – Most artwork and printing is conducted using four main file types: JPG (Joint Photographic Experts Group), TIFF (Tagged Image File Format), EPS (Encapsulated Post Script), and PDF (Portable Document Format).
BITMAP – Essentially, this is a photo in the computer consisting of pixels. JPGs and TIFFs are Bitmaps.
VECTOR – A shape made of an outline and a fill which can be manipulated. If you draw a box or circle in the computer, usually it will be a vector – made of lines and points which can be moved and changed.
DPI – Stands for Dots Per Inch and refers to the fineness or “resolution” of images. The more dots per inch, the higher the resolution. The standard for producing artwork which translates into good looking printing is at least 300dpi (90,000 dots per square inch) at the size it is being used. So, if you are taking photos for printing be sure to use high resolution settings.
A4 SIZE – 210mm x 297mm. A5 is half that size: 210mm x 148.5mm.
A3 is twice the size of A4: 297mm x 420mm.
DL SIZE – DL stands for Dimensional Lengthwise. It refers to an envelope which opens on the long side and is 220mm x 110mm. When referring to paper sizes it is what fits in a DL envelope, and is usually 210mm x 99mm – one third of an A4.
FOLDING to DL – When folding a standard A4 leaflet to DL size so it is easy to put in an envelope, or display, or carry, the two main options are “U Fold” and “Z Fold”. If you look at a partly folded A4 folded to DL leaflet from the bottom end you will see that it forms either a U shape or a Z shape.
DIE CUTTING – When the shape of a job cannot be cut with the straight lines of a guillotine, it must be Die Cut. This is done using a “Die” which is like a cookie cutter stuck to a board. After a job is printed and dried it goes through another “Press” which stamps out the shape required. Presentation folders are usually die cut, as are fridge magnets with rounded corners.
STOCK – This is what is being printed on. Generally, it refers to the type and weight of the paper or card being used. Most printing stock is divided into Coated or Uncoated. Coated stock has gone through a process in manufacturing when a coating of clay has been added before being run through rollers to provide a smooth glossy or smooth matt finish. Regular bond paper used in an office copier or printer is uncoated.
NCR – No Carbon Required, i.e. paper which is pressure sensitive so it can be used to make a copy without using carbon paper. Often used in Order Books, Invoice Books, and Receipt Books.
GSM – Grams per Square Metre refers to the weight of paper and card. If you weigh a square metre of the stock being used, that is how much it should weigh. Note that it does not refer to thickness unless you are comparing papers/cards manufactured the same. Average letterhead bond paper is 80gsm or 90gsm, sometimes 100gsm. The average glossy leaflet, which is about the same thickness as bond, is 150gsm. The average coated business cards is around 350gsm.
SADDLE STITCH – If you have a multiple page booklet with staples along the folded edge, they are probably not staples as used in a stapler, but are the result of being “stitched” by a machine which stitches with wire. It comes from a time before there were staples when booklets were stitched with thread to bind them.
If you need explanation of any other terms used in printing and artwork, simply contact Frog Print, and we’ll be happy to explain them.