3.2.11. Gray Excerpt
The color of a dot in a document (e.g. a MS Word *.doc or a *.html in Internet Explorer) before printing with EXTIF pro, is called original color. As the document is usually meant for being displayed on the screen, these original colors are generally RGB colors.
Equal portions of red, green and blue result in a neutral gray. As already explained in paragraph CMYK, in CMYK color space, especially the darker neutral gray can be obtained more cheaply and at higher color fidelity by adding a black (K-channel) portion to cyan, magenta and yellow, than by simply blending C, M and Y.
All common CMYK color profiles take this into account: They compose for example fullblack (R=G=B=0%) as the darkest neutral gray, by approximately 90% K, 80% C, 70% M and 70% Y.
In order to maintain the mix ratios of neutral gray as they are pre-set by the CMYK color profiles, select option No gray excerpt.
For text documents with embedded colored images, meaning documents with lots of fullblack pixels but few black-oriented color dispersions, it is recommended to completely represent the neutral fullblack (R=G=B=0%) of the original document (C=M=Y=0%) by K (K=100%) in print output. In this case, please select R=G=B=0% -> K=100%.
For documents that contain mainly gray scales, for instance text documents with embedded black-and-white images or gray scale images, you can go one step further by completely replacing the entire neutral gray with K. In this case, please select option R=G=B=x% -> K= (100-x) %. Example: If a pixel of a document has the original color R=G=B=37%, then the neutral gray will be represented by 63% K, 0% C, 0% M and 0%Y in print output.
Especially for smoothed fullblack writings on a white or neutral gray background, you should use R=G=B=x% -> K=(100-x)% instead of R=G=B=0% -> K=100%, as in case of a fullblack excerpt, an undesired Corona surrounding the letters in the C, M and Y channels would remain.