The effects of doubling-slurring on grey balance and dot tone value increase in offset printing

Abstract

Being in connection with the developing science and technology there have been great developments during the recent years in the area of printing and the same developments still go on. One of the most important ones of these is the technological advances accomplished in the quality controls during the printings. Together with the technological developments, quality-control in the printing can be implemented more objectively and with the same standard. Especially, the developments in the measurement devices such as spectrophotometer provide the achievement of correct measurements in color and density assessments. However, it is not possible to have the measurement of quality on the printed surface by only using these devices. Because, after proceeding to the clean printing, first doubling-slurring area must be viewed with the eyes on the control strips. If doubling-slurring problem is encountered in this area, there must not be a second measurement to follow unless the possible causes are eliminated. Because, even though the density of the ink, trapping values, etc., could be normal, there is the possibility to observe the artificial increase in tram tone values (dot gain out of tolerance) and then this situation is perceived as the printing is carried out with the ink having more density. The entire balances and force values of the machine must be done mechanically with Altona Test Suite or with the similar scale during the first installation. If these adjustments are not done during the installation or if they are deteriorated afterwards, doubling-slurring occurs. Having the printing force more than normal, blanket errors, rheological features of the ink, etc., L*a*b*, solid tone, trapping values must be measured with spectrophotometer after resolving doubling-slurring errors and the data must be interpreted according to ISO 12647-2:2004 and FOGRA standards. In general, dot tone value increase and grey balance problems are thought by the printing applicators to be caused by dot tone value increase and the problems of grey balance and by the printing pressure. Intensity values of the ink is firstly tried to be controlled in order to have the controls of dot tone increase and grey balance in the printing. Whereas, this is a wrong way of thinking on it's own. Because, dot tone value increase and grey balance problems causes is not only the abundance of the ink or the printing pressure. It is also required that the other effects causing this problems must also be examined. The study is done on the effects of doubling-slurring on grey balance and dot tone value increase. First the measurements of CMYK colors L *a*b*, dot tone value increase between 10%-100% and solid tone density values are measured on the test printing originals that are printed with standard conditions and having and not having doubling-slurring from UGRA 82 printing control scales. In the study, the effects of doubling-slurring problem on the grey balance and dot tone value increase are researched visually and numerically and obtained data are put forward with the graphics.