We receive so many discs each and every day, the majority of which produce files which we can print from without any problems. Occasionally though we get files which do not print as intended and are not what you, the customer, expected. This guide has been compiled to assist you with the stages of designing and setting up your files for print. It'll go a long way in helping you avoid extra costs incurred, by us trying to rectify your files.
When choosing different colours for your job, try to choose colours from the Pantone© colour palette if your software has it. If the job you require is to be printed in process, make sure these colours are converted to their CMYK equivalent. If your job is to be printed with a spot colour, check to make sure you have just one version of the spot colour. Some packages will have a CV or a CVC version of the same colour. A good way to check how many colours you have in your document is to print separations on your desktop printer. If you have more than the required number of sheets out of the printer, then you have too many colours.
RGB to CMYK
Your scanner, digital camera, computer and monitor use a combination of three colours: Red, Green and Blue (RGB) to create images. The printing process uses four colours to print the same images: Cyan (light blue), Magenta (cerise), Yellow and Black (key colour), commonly referred to as CMYK or process colours. At some stage the production workflow all RGB images have to be converted to CMYK. The conversion from RGB images to CMYK should be done before the file is sent to us in an image manipulation package like Photoshop. If this conversion is not done there is a danger that the standard RGB to CMYK conversion profile we use may make some of the colours appear to be washed out or dull.
Black isn't really Black
You may not realise, but a lot can be done with black to help you to achieve the desired results. To get the best from our process, black can be produced in two ways. The first method is single colour black, made from 100% black ink. This is ideal for small areas such as text.On larger areas of black solid single colour black can often appear grey or washed out. The way to achieve a dense black on large areas of black solid is to print a 40% Cyan underneath the 100% Black. This will give an even and dense colour as the second colour disguises any inconsistencies.
Set-off is the marking of the underside of a sheet by the transfer of ink from the sheet on which it lays. It can occur when pressure is applied during guillotining or simply while the Substrate is stacked. Set-off is caused by the fact that the ink is still wet, and is most prevalent on uncoated stocks. Set-off shouldn’t happen if you are careful about the weight of colours you pick. We have set some guidelines to help you avoid set-off or lengthy drying times. Our recommended ink coverage limit is 225%. This means that, wherever possible, the colours you use should contain less than a total of 225% when you add together cyan, magenta, yellow and black.
As part of our service, you have the option for us to supply you with a colour proof. If this is mentioned in the origination section of your estimate from us, then it is included. If not, for peace of mind, you may wish to request a proof. The proof is produced on our high-end colour inkjet printer which has been profiled to best match our machinery. The proof is not 100% accurate and is meant as a fairly accurate guide as to how your job will look.
If you are scanning photographs yourself, save them as either EPS or TIFF files as this will preserve the colour and clarity of your images. If you are scanning a previously printed item, such as a magazine photo, you will need to ‘de-screen’ the image, blurring it slightly to avoid a moiré effect. GIF or JPEG formats compress the image and actually discard information, causing colour shifts and blurriness. Don’t use either of these file formats – they may actually print in black and white and you won’t like the results.
When you are scanning, consider the final size that your image will be used at. Always scan photographs at 300dpi at the size you are going to use them. There’s no point scanning a postage stamp at 300dpi and then blowing it up to A4 size – use your scanning software to help you calculate the output resolution. Conversely, scanning photographs at more than 300dpi will have little or no effect on the actual printed quality and will unnecessarily increase file size and processing time. Don’t enlarge/reduce your scanned images in your drawing/vector software (such as Illustrator) – it’s always best to use an image-editing application such as Photoshop for this task. When converting photographs from RGB to CMYK, In the ‘edit’ menu choose ‘colour settings’. From the window that appears, choose ‘custom CMYK’ from the list in the ‘CMYK’ section of ‘working spaces’. Scanning flat or black and white line art (i.e. a logo), scan this at 800 to 1200dpi for best results. Any lower, and the logo may appear blurry. Pay careful attention to the CMYK makeup of any ‘black’ in the logo. The automatically created Photoshop black, for example, provides 250% ink coverage. You may need to adjust the colour settings in your application to get a black that is made from 100% black ink. Make sure that any alpha channels are removed and all layers are flattened before finally saving your image.