roman16 bvdm Reference Images

The series of motifs forms an aesthetically uniform family and at the same time contains all image criteria that are important for the assessment. Each image shows only a few objects, so even new users can identify processing and output problems quickly and without explanations or long searches.

A reduced visual language allows to establish differences in colour harmonies and their reproduction: uniform image format and section, lighting, subject distance, and proportions of the person and the background. In addition to the colours, close attention was paid to the optimal image definition in all sections, to fine details and to image sharpness. People, accessories, fashion, and backgrounds represent the primary, secondary and also tertiary colours in an appealing way.

The chromatic tone angles of the images in the ECI RGB colour space are guided by the corner colours of offset printing. The images are slightly more colourful and thus correspond to a real scene colouring. All basic colours are covered, especially those in which colour deviations can easily interfere. These areas lie outside of most CMYK colour spaces and therefore change the most due to the separation. When converting to a relatively small colour space, tonal value and detail can be lost and certain areas of the image may appear flat.

Changes in colour density and other irregularities in continuous colour gradients are the results of an irregular tone curve. A suitable gradient can be found in most reference images and was additionally placed next to each image as a gradient wedge. One image each in colour and black and white (BW) is dedicated to the highlights, midtones and shadows on the grey axis. One image each represents brown, olive and pastel tones, and there is an extremely colourful image. As a result, the roman16 bvdm Reference Images provide a good overview of all important hues in a colour space. In addition, the images contain a wide variety of skin tones which can quickly reveal even slight colour deviations.

The main purpose of the roman16 bvdm Reference Images is to check the conversion of RGB data into CMYK data for the selected printing condition, including

1. Assessment of output profiles by converting the RGB image data 

   • Checking of generic output profiles, e. g. PSO Coated v3 (ECI)

   • Checking of self-generated output profiles

   • Comparison of separation results on the monitor

   • Comparison of separation results by means of printed proofs (gamut mapping) and in a print run (black generation, tone value sum)

   • Comparison with reference file/CMYK or reference proof

2. Comparison of Rendering Intents (approaches to colour separation) 

   • Relative colorimetric with black point compensation

   • Perceptual

   • Comparison of colour space reproduction on the monitor

   • Comparison of colour space reproduction by means of printed proofs

3. Checking of different versions of CMM (Colour Matching Modules)

The RGB versions of the three black and white images can be used to check the grey reproduction and the black composition of CMYK printing profiles. A sample application is a black and white ad printed in four colours for better contrast.

The CMYK versions of the three black and white images can be used to assess the grey reproduction, the mid-tone spread and the ink trapping of a print run.

The grey scale versions of the three black and white images, in turn, can be used to assess the black simulation of a digital proof printing system. Besides black ink, such systems also use the chromatic colours to simulate single-colour printing with black ink. This can lead to different colour casts in different tonal value ranges of the proof print.

16 reference images in the following file formats:

• RGB 16 bit 700 dpi (16 files),

• Grey 16 bit 700 dpi (3 files),

• CMYK 8 bit 700 dpi, separations with ISO Coated v2 (ECI) (16 files),

• CMYK 16 bit 700 dpi, separations with ISO Coated v2 (ECI) (16 files)

ICC profiles eciRGB v2 and ISO Coated v2 (ECI)

Characterisation data FOGRA39 and FOGRA39L