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02. Preparation of Materials to be Printed
Preparation for the exposure room
Advertising material must be prepared for exposure - separation must be performed, as well as a copy to a file in the PS or PRN format.
- For this purpose, bitmap images in the CMYK mode (not RGB!!!) should be used;
- All the decorative font types in the text should be converted into curves;
- If a folder includes a paragraphed text (in boxes) and a non-standard font has been used there, fonts should be placed in a separate folder and submitted together with the leaflet;
- Each design should be accompanied with a .TXT file with the information on the leaflet size, exposure (ruling and resolution), and the data of the person who has made the design (phone number, e-mail address);
- While designing a leaflet, the standard settings of the CMYK colour palette should be applied. If PANTONE colours are used, information should be enclosed that such colours have really been applied to the design;
- Each design should be accompanied by a file with an image of a given design, in the .JPG format, which will serve for checking its conformance with the printout on films;
- Preparation for exposure is free of charge.
- Our exposure room shall not bear responsibility for errors in the design submitted.
Exposure in the CTP System
Procedure of preparation of files for exposure in the CtP system (using the Corel Draw application):
- In the design to be processed, the ‘Publish as a PDF file’ should be selected from the ‘File’ menu;
- In the newly-opened window, the ‘PDF for printing works’ item should be selected from the ‘PDF style’ list. The Corel application will set optimal values of particular parameters, so only two things have to be done:
- The ‘Export all texts as curves’ option from the ‘Objects’ menu should be activated: then all the other text options will become inactive;
- The ‘Use colour profile’ function should be unchecked in the ‘Advanced options’ menu.
- At this moment, all the options have been defined appropriately and all you have to do is to save the .PDF file by clicking OK. If the options have been set as described above, you can press the ‘+’ button available at the PDF styles on the first menu, and the selected options will be recorded as a ready-made profile. The Corel application will remember the last profile used, so the whole task will boil down to selecting the location and name of the file and setting the range of the pages to be published.
Please, note that as a result, you will obtain a composite, on which certain important elements, such as overprints, are invisible, unfortunately. A serious problem is related to this fact. In the case of post-script files, Corel used to offer the ‘Black always overprinted’ option, whereas nowadays this option for overprinted objects must be set manually, by right-clicking on the given object and selecting ‘Overprint the inside/contour’. This can be done in another, simpler way, but it is one of the professional secrets of our graphics experts, which we might reveal in the future.
Pictures to printed
Resolution and colours are retained best in the .TIF or .EPS formats. GIF and .JPG files are met most frequently, as they occupy much less space, but unfortunately they simplify colours and decrease resolution. Usually, they are found in the Internet, where their basic resolution is 72 dpi, whereas in the case of a printout, this value should amount to 300 dpi.
Therefore, please pay attention to the source of your materials and remember that what looks good on your computer display will not always look the same as a hard copy. In conclusion: pictures from the Internet are not good enough for professional printing.
Scanning is the main method of obtaining a picture for an advertisement. Please, remember that after scanning an image at a resolution of 300 dpi you cannot magnify it using your typesetting application, as you will lose the basic resolution and the picture will be out of focus.
Pictures from digital cameras or video cameras may be used. If they are recorded correctly, at a large resolution, they will satisfy the requirements for printing. If you have a picture at a resolution of 72 dpi, you can calculate that this constitutes 24% of 300 dpi, whereas your camera shot pictures at a resolution of 1024x768 (i.e. 36.12 cm by 26.04 cm). Consequently, you will have to diminish the size of that picture by 24% to obtain 300 dpi resolution.
Furthermore, images may be downloaded from various royalty-free Internet services, where after you have paid a charge, depending on the type of the source and the intended picture use, a file at an appropriate resolution is sent to you. Such pictures are the best, as most frequently they are provided in the .TIF or .EPS formats.
Numerous typesetting applications offer a selection of a colour palette suitable for a given mode of operation. However, it must be remembered that the colour spaces in particular modes are not fully equivalent. If colour conversion is effected during a late stage of designing or at the very end, it may turn out that the final effect is not satisfactory. Anyway, if we want a printout, conversion from the RGB mode (applicable to computer displays, digital cameras and TV sets) to the CMYK mode is necessary. As a result of a change from the RGB to the CMYK mode, the ‘Colour space alert’ warning may be displayed. Such a situation means that there is no precise counterpart for an RGB colour in the CMYK mode. Very often, a change in the graphic mode will not be disadvantageous, as the differences may be insignificant.
To avoid colour-related problems and unpleasant surprises, it is worth buying the CMYK Process Colours Guide, which will enable us to see how a change in the ratio of particular paints influences the colour of the printout.