All about spot colors

Akash Choudhary // February 21, 2020

PDF in general Member News

Some printing processes do not use CMYK process inks at all, instead only spot inks are available, and sometimes even a relatively small number. Furthermore, in some cases half-toning does not work at all, and thus it may not be feasible to overprint spots with each other to achieve mixed ink colors. This may be due to the way the printing process works like for the production of marketing materials such as pens or cups where for example, pad printing (tampon printing) is used, you can only use spot colors and cannot mix them on the substrate. Another problem could also go back to cost considerations, for example when imprints on small give-away items must be as inexpensive as possible and thus use only two spot colors. For such scenarios, print ready PDFs should only use a specific number of spot colors, and always at a 100% tint value.

Usually print shops have a rather big number of spot colors that they can use. Up until today their customers could upload their logos / icons and the print shop had to try to match it as closely as possible. As a print service provider, you would usually not decline a print job just because the print file has not been prepared perfectly well. You would rather want to turn an arbitrary PNG or JPEG image, or an arbitrary PDF, into a print ready PDF file that only uses a specified number of spot colors, but you want to do that in a way that makes the best possible use of the set of spot colors that you have at your disposal. With Spotify, it becomes possible to do that in an automated way. It would even be possible to integrate that into a web application and let the customer pick one of several possible variants.

We define 'Spotify' as the process of turning an image into a PDF page which uses

  • one or several spot colors only,
  • each at a tint value of 100%, and
  • without any overprints,
  • while maintaining the original appearance of the image as closely as feasible.

Having read until here, I am sure that you are wondering about the possible use cases of Spotify. From pad printing applications like printing on medical devices, apparel industry for printing labels directly on clothing or promotional gifts like on a coffee mug and give-aways to metallic ink printing on tiles or notepads, this is where the new Spotify feature in pdfToolbox comes into play. Based on a complex analysis process, and controlled by a number of user configurable parameters, it derives the spot colors that offer the best appearance match, and assigns these to the respective areas of the original PDF, in order to provide a clean looking and pleasing result.

pdfToolbox allows you to use Spotify in almost all the possible flavours. It can be used as an action, which works in the same way as the Fixup, but offers access only to the two most relevant parameters and thus is easier to use. It can also be used in the CLI version. My personal favourite to play around is the Spotify inspection tool which lets you immediately see the effects of each parameter and lets you fine tune the process by providing an advanced setup view, like below:

Now that I have your full attention, learn more on 'How to use Spotify' watching this video.


ABOUT THE AUTHORS

Akash Choudhary

Akash Choudhary, Product Manager at callas software GmbH considers himself as a lifelong student of PDF products and technologies. With a bachelor’s degree in Computer Science and Engineering and a Master of Business Administration (International Management), Akash has gathered experience in small and big firms in software performance testing, marketing, business development and social media and content manager. Working as …

ABOUT THE AUTHORS

Akash Choudhary

Akash Choudhary, Product Manager at callas software GmbH considers himself as a lifelong student of PDF products and technologies. With …

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