There are lots of things that can go wrong when you send images to be printed by a commercial printer, either stand-alone or as part of a DTP layout (eg InDesign). Here is a list of things to check before you send your files to the printers - read and follow these guidelines and save yourself some potential trouble and expense!
Firstly, TALK TO THE PRINTERS! This may seem like an obvious one, but a phonecall to ask a few questions can save you a reprint and additional cost further down the line.
Be aware that the printers you use are probably using custom colour profiles tailored to their output devices. This is going to differ from the colour profile embedded in your image. It is wise to use a standard colour profile like ‘Euroscale Press’ if you are based in Europe as they will be able to convert the profile to their own easily. Using custom profiles made by yourself is asking for trouble as they don’t have a reference point to being with! Techies love messing around with colour profiles, but believe me - you are much better off using a standard profile that comes with Photoshop that is appropriate to where you and your printers are based. Once again, talk to your printers about this if you are at-all unsure!
It is not always possible to request a proof or ‘wet proof’ from the printers on small jobs due to cost implications - but don’t try and save the money and not have a proof if you can afford it! That way you can check colour and output without having to pay for a reprint if things go wrong! You can also show this to the client and get them to approve it.
Always provide the printers with a high quality proof print of your artwork along with your digital files - either from an inkjet or laser printer. That way they know what you are trying to achive and this can save a lot of trouble down the line. Inkjets in particular can have a wider colour gamut than lytho print, so be aware that some of the colours may not be as vibrant. This is also effected by the paper used, coated paper gives brighter colour reproduction than uncoated paper stock. Your printer should be able to advise you on this.
Don’t supply your printers with the original 500 meg layered Photoshop document, they only want flattened artwork. Save your image as a TIFF with LZW compression. It could save you potential additional print setup costs as they will have to flatten the file (and potentially miss out that all-important layer!)
Always use CMYK colour for normal full colour print, not RGB or indexed colour. There are certain cases that you may use RGB colour for digital output but once again, ask your printer. If you are at-all unsure, stick to CMYK. Stay clear of special colour channels (those that use Pantone inks) unless this is built into the print budget and is absolutely necessary - introducing these will add additional costs to the job.
Ask your printer what resolution, or DPI they wish the file to be setup at. For anything A3 sized or smaller 300dpi should be fine - bigger images can be saved at lower DPI in most cases.
Text can be a big problem in image files, particularly if it is very small. Text should be set in another application like InDesign or Quark for perfect quality output - just remember to either include the fonts if you are on a Mac or turn your type into outlines if you are on a PC. Macs don’t get on too well with PC fonts and professional printers will have big problems with them. If you turn your type into vector outlines you won’t have to worry about this - just remember to save an editable file for you to keep so you can amend the text at your end!
Finally, remove all alpha channels and paths from the flattened file - these will will only confuse the printer, and particularly in the case of alpha channels increase the file size.
Keep it simple and you shouldn’t have too much to worry about!
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