title: [The influence of printing technology conditions on the accuracy and reproducibility of printed contrast panels for assessing contrast sensitivity].
abstract: OBJECTIVE
  Contrast studies can provide important knowledge for treatment decisions before surgery or for assessing the driving ability of professional drivers. Accordingly, high demands are placed on contrast panels to obtain reliable and reproducible results. The aim of the study is to find out if the contrast panels on the market meet the requirements.
  
  
  METHODS
  On the basis of measurement evaluation and schematic presentations potential sources of error can be identified. These sources of error may have a decisive influence on the assessment of contrast vision.
  
  
  RESULTS
  Far-reaching analyses have shown that three parameters can have a significant influence on the accuracy and reproducibility of printed contrast panels. This holds for certain properties of the printing substrate, the type of representation of display element, and the choice of the colourant. Only the correct interaction between the substrate and the print colour effects an angle-independent contrast. A matt substrate is necessary, which has a low difference to the printed contrast element in respect of glow, so that possible angle differences have no influence on the contrast assessment. The contrast elements of a contrast panel vary in brightness. Conventional methods for typographical representation of different brightnesses use the method of screening. This causes undesirable edges, which weaken in particular the lower-contrast elements unintentionally. Use of special colours can avoid this effect. In the visible wavelength range the studied contrast elements have an irregular absorption behaviour. Because of differences between the lighting surroundings, this can lead to a differentiated stimulation of cones in practice. Appropriate colourants have a constant absorption behaviour.
  
  
  CONCLUSIONS
  To get representative results of contrast studies the production of contrast panels needs more knowledge about the interaction between paper and colour than is typically required for print products. On the basis of a prototype optimisation, approaches are presented in this article.
authors.affiliation: Druck- und Medientechnologie, Bergische Universität Wuppertal, Campus Freudenberg, Wuppertal.
authors.forename: T
authors.initials: T
authors.lastname: Raabe
authors.affiliation: Druck- und Medientechnologie, Bergische Universität Wuppertal, Campus Freudenberg, Wuppertal.
authors.forename: U
authors.initials: U
authors.lastname: Jung
authors.affiliation: Augenheilkunde, Universitätskliniken Tübingen.
authors.forename: H
authors.initials: H
authors.lastname: Wilhelm
mesh_terms: D015350:Contrast Sensitivity; D006801:Humans; D011237:Predictive Value of Tests; D011327:Printing / Q000379:methods*; D014787:Vision Tests / Q000379:methods*