Details:
Summary:
There is an increasing focus on cost reduction in the printing industry. This has led to the implementation of many quality strategies and manufacturing methodologies that include lean manufacturing, just-in-time and six sigma. In many of these the objective is to standardize and evaluate the workflow throughout the production workflow. By evaluating the costs of manufacturing the press consumables will contribute significantly to the final cost of the product. The final breakdown of consumable costs will depend on the actual production piece, the market served and the complete run length. Considering consumables, paper is the most significant proportion of the production costs, and much work has been carried out optimizing the press configurations, product sizes and trims to minimize the amount of waste in this area. Ink, in many cases, is a significant cost and there is a great deal of investigation into different strategies for reducing the ink usage from changing the material properties (ink, paper etc.) through to ink reduction strategies in pre-press. This paper focuses on the different ink reduction strategies that are available in pre-press and how they impact the print quality and ink usage. The ink mileage savings in pre-press can be achieved in a number of different ways. There are two main methods for carrying out the optimization process. In the first case the algorithms can be applied during the RGB to CMYK conversion. In this case, due in many cases to the gamut compression between original and destination color spaces, there will be a color shift in this conversion application. The second case that the optimization can occur will be in the taking a set of existing CMYK separations and converting them to a new CMYK data set. In this scenario the objective is to maintain the original color intent from the first set of data files. For several years the technique of Gray Component Removal (GCR) has been used in Photoshop and can be used on images within a color managed workflow. Default settings or custom GCR levels can be used for the separation. There has over recent years been the introduction of new commercial packages that can be easily integrated into the workflow to facilitate the file conversions, be they RGB to CMYK or CMYK to CMYK. The study has used a number of standard test images to assess both the possible ink savings and also the color accuracy of the conversions. These represent a wide range of typical images from a commercial operation. In addition, files from a production job have also been assessed. The different default levels of GCR have been assessed. Earlier work had shown that the custom GCR if not properly optimized would give rise to artifacts in the images and as such was excluded from this study. Secondly, a number of commercial packages available that can be used to facilitate the separations have been assessed. The files were run through each of the different systems using their default settings. The resultant separation files obtained were reviewed, assessed and analyzed for a two main factors, namely the ink savings obtained by the separation and secondly the color accuracy / artifacts. To aid in the assessment of the color accuracy / artifacts proofs were produced of the images and these were assessed by a panel of experienced color experts. The results show that there are significant differences in the ink usage between the different approaches. However, in certain instances the savings come with a change in the quality of the image.