What is Prepress?
Prepress, also known as colour separation in Malaysia, is a vital stage in the printing process. Historically, it referred to the process of preparing artwork for printing by separating colours into the four components of CMYK – Cyan, Magenta, Yellow, and Key (Black). This separation was necessary for offset printing, where each colour was printed using a separate plate.
During the 1990s, colour separation was a thriving industry in Malaysia. At the time, the machines required to produce films for printing were massive and highly expensive, making colour separation companies essential players in the printing process. These companies often employed over 40 people and required significant expertise to operate the equipment. However, the landscape changed dramatically with the invention of direct-to-plate (DTP) technology and the introduction of more affordable printing machinery, particularly from China. These innovations significantly reduced costs and led to the decline of large colour separation operations.
Today, most colour separation businesses in Malaysia are smaller, typically employing fewer than 15 people. Despite the shift, their role remains indispensable to the offset printing process, as printing cannot commence without proper prepress preparation.
Why do prepress?
Prepress is critical for ensuring that the transition from digital design to print is smooth and error-free. It involves several steps to optimize artwork, adjust colours, and prepare printing plates. In the past, this was an arduous and time-consuming task. Designers and art directors often had to visit colour separation companies at odd hours, such as 2 a.m., to inspect calibrated monitors and printed proofs.
The colour separation experts would then create a printed proof for review, and any identified issues would require reworking the films and proofs, often involving multiple rounds of adjustments. While these methods were effective, they were labor-intensive.
Today, technology has streamlined the process significantly. Designers can now create high-quality PDFs and send them directly to printers, who handle the prepress tasks, including digital colour proofing and plate production. However, many designers overlook the importance of understanding the prepress process. Familiarity with prepress ensures better Final Artwork (FA) preparation, saving time, reducing costs, and improving the overall quality of the printed material.
The Main Steps in Prepress
1. Colour Quality
Images must be converted to CMYK, as RGB is suitable for screens but not for offset printing. Tools like Photoshop are standard for making colour adjustments. Using features like Curves or Auto Contrast can enhance image quality for print.
When using stock images, it’s often sufficient to convert them to CMYK without further adjustments, as most professional stock images are pre-optimized.
2. CMYK Black vs. Solid Black
Black areas in CMYK can appear muddy or “fattened” if other colours (Cyan, Magenta, Yellow) are inadvertently included. To avoid this, ensure black text or graphics use 100% K (black) for a clean, professional appearance.
For richer black backgrounds, use C30 M30 Y30 K100. However, for small white text on a black background, using C30 K100 is advisable to maintain clarity.
Check CMYK black with Separation Preview
3. Printing Resolution
The resolution of all images should be at least 300 dpi to ensure clarity and detail in offset printing. While file formats like TIFF, PSD, and JPEG are all suitable, PSD files are preferred for editing flexibility, whereas JPEGs save storage space.
4. Create Outlines for Fonts
Converting fonts to outlines ensures consistency, preventing issues where fonts might display differently on another system. It also protects the design from unauthorized changes.
Finished artwork with create outline
5. Registration and Folding Lines
Include registration marks to indicate where the design will be cropped, as well as folding lines (if applicable) to guide post-printing processes. These are typically shown with perforated or dashed lines.
6. Bleed Areas
To avoid unwanted white edges after cropping, designs must extend at least 3mm beyond the trim line on all sides. This bleed area ensures seamless edges, particularly for background colours or images.
7. High-Quality PDF Creation
After verifying that all images are in CMYK and all text is properly outlined, create a high-quality PDF. This file is sent to the printer, who will review it and prepare digital colour proofs for client approval.
Pantone Colour in Printing
Using Pantone colours ensures brand consistency, especially for companies with strict corporate identity guidelines. Pantone provides standardized colour matching, which is critical when exact colour reproduction is required across different print runs and materials.
If a design includes a Pantone colour, the printing process will require an additional plate specifically for that colour, beyond the standard CMYK plates. This means a total of five plates (or more if multiple Pantone colours are used) will be needed for the offset printing process. Keep in mind that incorporating Pantone colours can increase production costs, so it is advisable to balance design requirements with budget considerations.
Special Print Finishing
Adding special finishes like gold or silver hot foil stamping and Spot UV can significantly enhance the appearance of brochures, packaging, or other printed materials, giving them a premium and eye-catching look.
Gold / Silver Hot Foil Stamping:
This technique uses heat and pressure to apply metallic foils to the print surface, adding a luxurious and reflective element.
Spot UV:
This involves applying a clear, glossy coating to specific areas of the design, creating contrast and drawing attention to key elements such as logos, text, or images.
For both finishes, additional printing plates are required to define the areas where the effects will be applied. These plates are separate from the CMYK or Pantone plates, making the setup more complex.
Conclusion
Prepress is essential for ensuring that designs translate seamlessly from digital formats to high-quality printed materials. While digital printing bypasses many of these steps, offset printing remains the gold standard for quality and cost-effectiveness in larger print runs.
A reliable prepress partner provides accurate digital colour proofs, allowing you to visualize the final outcome and make necessary adjustments before printing begins. By understanding the prepress process and working closely with your printer, you can save time, reduce errors, and ensure your printed materials look as professional as intended.