What is Prepress?
What is prepress?
In Malaysia, it is also call colour separation. Because during the olden days. We need to output film in CMYK – Cyan, Magenta, Yellow and Key colour (black). So the process is separated into 4 colours in order to do printing.
In the 90s, colour separation was huge in Malaysia. Because the machine that output film is big and very expensive. A colour separation company usually have more than 40 stuffs. After the direct to plate machine was invented, and many cheaper machines from China came into Malaysia and replaced the film machine, the pricing had since dropped dramatically.
Nowadays the colour separation in Malaysia are mostly in moderate size of less than 15 people. But they are still consider important because without them, offset printing cannot proceed.
Why do prepress?
I remember that during those day we have to go to the colour separation company at 2am to check the colour on their monitor, which has been specially calibrated to offset printing colour.
The colour separator then do printed colour proof. The art director will check and highlight the problems on the proof. And then the colour separator will go back and redo the colour film and proofing again. It was very time consuming.
But nowadays, designer will check image colour, artwork in the computer and just create a high quality PDF and mail to the printer. Normally the printing company will engaged a colour separation company to output the digital colour proof and printing plates.
Today, many designers will just overlook colour separation in printing process. If designers understand better about the process of prepress, they will do a better job in FA. Eventually will help you save time and cost for printing.
Let’s have a look at a few of the main steps to go through before sending a design off to print.
1. Color quality
When you received an image for the design, we suggest that you convert the image to CMYK. RGB is normally colours for television and monitor. It is not the right format for offset printing.
Photoshop is standard in doing colour adjustment. Go to selecting image and scroll down to adjustment. Used the curve to adjust the image. You can also use auto contrast to adjust the contrast of the image.
Sometimes when I buy stockimages, colour have been adjusted. So I just convert the image to CMYK and save in jpeg. The stock-image’s ‘shifu’ already adjusted the colour, no point to try and better them.
2. CMYK Black
One of the major issue that we have encountered is black copy in CMYK. When it is printed. The other colour cyan, magenta and yellow will make the printed black copy look fattening. You will still see little bit of other colour on the black. It will make your printing look very unprofessional.
In order to check your artwork whether it is in RGB or CMYK in Illustrator. Go to window and scroll down to separation preview. Deselect the key colour and you will know that the black is a 100% black or a CMYK black.
If you want to make the black background colour more solid, used C30M30Y30K100. On the other hand, if you black background have small reverse white fonts, we would suggest C30K100.
Check CMYK black with Separation Preview
3. Printing resolution
They always argue to use which format for printing. Images can be saved in Tiff, PSD, jpeg etc. I don’t want to drilled into all these but so far I know that it doesn’t affect the printing quality that much because technology already improvised that all can be used.
Most important for offset printing is the image quality must be 300 dpi. I normally use PSD because I can always go back to Photoshop to adjust the colour. Jpeg file is smaller and will take up less memory in your computer.
4. Create Outline
The main reason to create outline is because of the fonts. There are so many fonts out there and designers like to explore fonts for their design.
Without outline, there has been cases that the fonts will run even though the colour separators have the font with the same name. The artwork will look different from the designer.
Another reason is that to avoid anyone from changing your artwork. Always create outline to safe guard your FA.
Finished artwork with create outline
5. Registration and folding line
Whenever we do finished artwork, we must put in registration line to show where the printing will be cropped or where is the folding line. Normally we used perforated lines to show folding area.
If there is no folding line, you can use illustrator to create the high quality PDF with registration lines. Otherwise you have to show the folding line in the artwork.
6. Bleeding Area
Registration line will provide you with the cropping size. You should make sure that your artwork size have extra bleeding for cropping. Normally 3mm extra all side will be safe.
Including the images, you should ensure that it is 3mm extra out of the registration area so that after cropping, there will not be any white gap on the side.
7. Create a high quality PDF
Final checked all images are CMYK. All the black copy are solid black, not CMYK. After final approval by client. You can create outlne and save as a high quality PDF and mail it to the printing company. They will pass your PDF to the colour separator.
A good colour separator will check your file again and make sure that everything is correct then they will output a digital colour proof for you to show your client.
Colour proof should be checked by the both client and designers. Because designer work on the design, they will know better if anything is missing. After these final steps, you can proceed with offset printing.
8. Select the right paper
Normally printing with matte paper will be more subtle. With gloss paper the outcome will be brighter and colour more vivid. If you are targeting environmental friendly customers. You can consider recycle paper. Depending on your target audience, luxury product should use more premium paper.
All papers will give you different quality of printing. Talk to your printing company and request them to show you some samples.
Conclusion
The prepress is only applies to offset printing. If you are doing digital printing, no plates are involved. You only need to pass the high quality PDF to us and we can proceed with digital printing.
In term of printing quality, offset printing is still consider better than digital printing. And if you are printing in quantity, the cost of printing will be cheaper compare to digital printing.
Choose a printing partner with reliable prepress that provide quality digital colour proof, so that what you see is what you get. It will definitely help you in the process of printing.