We explain some of the most common graphic designer terms to help you understand your dpi from a pdf, and the bleed from the crop marks?
Colours : What are RGB and CMYK
RGB stands for each of the primary colours of light that make up an image. RED, GREEN, and BLUE – your monitors, TV screens, and phones all display images using RGB.
CMYK is for printed material with ink – the letters stands for CYAN, MAGENTA, YELLOW, and BLACK. These collelate to the standard coloured plates on a printing press.
The K actually stands for Key. In traditional printing the Key Plate is the plate that holds the most detail in the image (usually black). The remaining plates (Cyan, Magenta & Yellow) are carefully keyed, or aligned, with the Key Plate.
In general designers tend to create artwork, regardless of its end use, in RGB. This is because programs like photoshop have more flexability and functions available for use in RGB compared to CMYK.
When a project is ready for print, the files will be converted to CMYK.
There are occasionally some drawbacks of working this way – some colours, especially the vibrant colours do not convert perfectly to cmyk ,so you may notice some colour shift to the closest matching cmyk colour when this happens.
High and Lo res
The terms graphic designers use to talk about the quality of an image is normally the res, or resolution. This relates to the quality of the image. A low res image will be a small image with poor definition, whereas a high res image will be large in size with good definition (assuming the original image is sharp and in focus)
DPI stand for dots per inch, and relates to the resolution of an image in print. The higher the dpi the better the resolution.
It is however worth remembering that whether an image has a high enough dpi depends on the end use of the image. The question isn’t “is the image high res”, but is it high res enough for your use?
Pixels refers to the size of a digital image for use on screens. These are not talked about in graphic designer terms of dpi (as they have no physical size), but in terms of pixels. An image for use on a mobile phone screen and a wide screen TV may have the same number of pixels covering the width, and therefore the pixel size will be the same for each.
A common mistake on specs sheets for online imagery, is when a pixel size is given along with a DPI size. Eg: 2000×3000 pixels @ 72dpi. This terminolgy does not make sense in design terms.
Whilst an image to be printed will have an equivelent pixel size on your computer, a final use screen image will not have an equivilent print size.
In printing, bleed is the printed area that goes beyond the edge of where the sheet will be trimmed. In other words, it is the image area that bleeds past the edge of what is needed that will be cut off. This area gives the printer a small amount of space to account for movement of the paper, and design inconsistencies.
The dashed line on the image below shows where the design will be cut by the printer. Any thing outside of the line is the bleed and will be removed.
These are printed marks on the paper that the printer will use as a cutting guide to be able to crop the paper. Only the final print ready files should have these marks on them.
When working in photoshop the document is made up of lots of different groups of layers that form the image. Different layers can be turned on and off to show different parts of the image as it is built.
The layered file is therefore simply the photoshop psd file. Some people confuse this graphic designer term to mean the full artwork files (see below), as it is often used as a shorthand to mean that.
Once complete a layered psd file will be converted to a flat cmyk file to get it ready for print. Typically the psd file is flattened to a single layer, and the colour mode changed to CMYK. This file is then saved as a .TIFF file. Should you need to alter anything on the psd file you will need to repeat the above steps to create a new flat file.
Artwork files refer to all the files that work together to make a final design. Designs are often created using a page layout program called Indesign. This program is where the image is imported into, and then the text and logos are added and styled within it. Creating a final print ready pdf from Indesign is often the best way to make your final print files.
There is a function in Indesign called “collect for output” where the indesign file ( INDD) is collected into a new folder along with all the images and fonts that make up the layout. This folder full of all th efinal artwork files can then be sent out to those who need it.
If the imagery had been made as a layered psd file, and then saved as a flat CMYK file for print ( see Flat Files above) , then the indesign collection function will not collect the original psd file, as it was not part of the final design. If this is the case then the layered psd file will need to be supplied seperately.
Print Ready Files
One of the most common graphic designer terms is for when a design has been approved. A designer will prepare your files to get them ready for print. This process includes around a dozen checks and changes to the files to get them prepared. It includes things like converting the images to CMYK, or changing all the fonts to outline. All this needs to be done in order to make sure there are no errors on press.
There are dozens of different standard paper sizes dependant on your needs and final use of the deisgn – we have written a post specifically about all these options here.