The preferred and safest format is a print-ready PDF which has ideally been exported from design software such as Adobe InDesign or Adobe Illustrator.
Files from Illustrator (.ai, .eps) and Indesign (.indd, .idml) are acceptable as long as all fonts and linked elements are included in a zipped package.
Word files are not print ready and usually require extra work and cost to make them suitable files to print from.
As a general rule if you ensure that all of your photos and graphic elements are high quality when creating your design and ensure that you save at a resolution of at least 300 dpi the results will be good. Try not to be tempted to use software that claims to increase the quality of a low res image as the results are often not as you would expect.
When happy with your design, convert all fonts into curves or outlines. This will ensure that your type stays exactly as you have designed, otherwise there is a risk that a different version of your font will be picked up and used when the file is sent to print. Or worse something will move!
Vector Graphics are great for use in logos and icons because they are scalable, which means no matter how large they are printed they will always look nice and sharp.
Bitmap Graphics are made up of pixels. When using a bitmap image be sure to check the resolution is at least 300dpi as once they are scaled up they will become pixelated and look poor quality on the printed item.
If your photos or lines bleed off from the edge of the print then allow 3mm of bleed around all edges as a minimum, otherwise you could be left with an ugly uneven white edge or worse the job has to be trimmed smaller than you’d like.
Most applications make adding crop marks easy, it will appear as an option when saving the file. Crop marks ensure your job is trimmed to the correct size and position.
All artwork should be supplied in CMYK format. Artwork supplied in RGB mode will need to be converted to CMYK and this always creates colour differences.
If you are using spot colours remember to use a colour from a Pantone swatch and remember that not all pantone colours convert to CMYK and remain exactly as the original colour you have chosen. Spot colours are really only relevant if your job is going to be printed on a litho press so please have a chat with me prior to creating your design if you are unsure.
If your artwork has drop shadows or a blur then remember to flatten transparency as these elements can often be unpredictable. Have a chat with me if you are unsure how to do this.
If your print job requires a cutting forme then please remember to set the cutter guide to magenta and have these as a separate layer.