User Manual


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OBA values - Optical Brighteners

Optical brighteners are additives that paper manufacturers put into paper in order to help a paper look "whiter." They are also called optical brightening agents (OBA), fluorescent whitening agents (FWA) or sometimes "artificial whiteners."

In order to make paper appear brighter, it is common for most paper manufacturers to add certain chemicals to the paper which can take invisible ultraviolet light and cause it to re-emit in the blue spectrum - or fluoresce - at a point that is just barely within our ability to see. While our eyes see this as a brighter, blue-ish white - a light measuring instrument will only see this as a different form of blue. For this reason, printer profiles made with paper using a lot of optical brighteners can produce images that have a yellow tint to them. The profile is trying to correct for what it sees as too much blue in the paper.

Virtually every paper that has a noticeable bright white appearance has some amount of optical brightener. Examples of paper with OBA in it are common office bond paper, Epson Premium Matte, Luster, Glossy, etc., and most every other brand of commercial inkjet paper. The chemical agents in paper causing this fluorescence will lose their effectiveness over time so that over the course of several years, the apparent brightness of the paper will decrease. It won't be "glowing" with the artificial white that it did when new. This is part of the reason why some people choose to print with "natural" papers.

The OBA value can be calculated as follows:

  • Measurement of the paper with M1
  • Measurement of the paper with M2
  • Difference of the b-value of M2-M1

The OBA values can be interpreted as follows:

  • OBA value = 0: no optical brightener
  • OBA value = 0-4: Little optical brightener
  • OBA value = 4-6: Medium optical brightener
  • OBA value > 6: A lot of optical brighteners

Optional Content Groups (OCG's)

PDF does not have a layer construct, as is the case in graphics applications such as Adobe InDesign, Adobe Illustrator or Adobe Photoshop. Layers are referred to as Optional Content Groups (OCG's) in PDF. As the name suggests, OCGs in PDF were initially designed to make content optionally visible or invisible.  The following table explains the differences between the two:

Table 1: Layers vs. OCG's

Hierachical Layers Optional Content Groups
There must be at least one Layer on which all objects are located. OCGs are not required. The PDF itself serves as a container for all objects.
Layers are defined for the entire document. This means that every page or Artboard uses the same layers, layer names and layer hierarchy. OCGs can vary from page to page, as they are defined for each page.
A hierarchical layer serves as a container. Every object that is placed on it must be on one layer and individual objects cannot be placed on multiple layers. Individual objects can be located on none, one or more OCGs. This is because the OCG is more an attribute of the object itself rather than a superordinate container.
Layers are hierarchical. Objects on a higher layer cover objects on the layer below.

The hierarchy in an OCG is handled separately and it is not the entire OCG container that is arranged hierarchically. This means that PDF objects that are arranged in the foreground but also in the background in the PDF can no longer be visible if a layer is hidden.

Possible OCG status

In PDF OCGs can have different statuses. The most common statuses are the following:

  • Locked / Accessible – Thereby, block access to objects of OCGs.
  • Visible / Invisible – Thereby, hide or show objects of OCGs.
  • Visibility status – the visibility status of an OCG can have the following features:
    • is only visible when the Layer is activated / on
    • is always visible even when the Layer is hidden
    • is never visible although the Layer is shown
  • Print status – the print status of an OCG can have the following features:
    • only prints when the Layer is visible
    • always prints even when the Layer isn't visible
    • never prints although the Layer is visible
  • Export status – the export status of an OCG can have the following features:
    • only exports when the Layer is visible
    • always exports even when Layer is invisible
    • never exports although the Layer is visible

Optimized Saving

Optimized saving is also known as linear storage. Thereby, all incremental attachments are incorporated into the file structure which results into the file being saved in the smallest possible file size.

Figure 1: Comparison of the file structure of a PDF file incremental (left) and linear (right)


The advantage of optimized saving is therefore the smallest possible file size of the document. The disadvantage of optimized saving is the processing time as the process of saving the file takes a little longer than usually.

Optimized saving of documents

By selecting the Save as... command in applications, the document is usually always saved in an optimized format. Some graphical applications, such as PDF Editor, have their own menu commands for optimized saving of currently open documents.

Output Configuration

Output Configuration : If a Production Job has been created, the Output Configuration can be changed according to the requirements of the customer or other desired output results. This is necessary for example if the print must be suddenly produced on another machine, or on another material. The output configuration can be changed using the Output Configuration tab.

Output Intent

The output intent describes the final target device with which the color is reproduced in the PDF document. The Working Color Space is overwritten while being displayed and printed. The output condition is described with an ICC profile. The output intent contains an embedded device profile that defines the Color Space of the target device, for example PSO Coated V3.


Overlap – Describes the additional area needed for gluing individual tiles.

See the following link concerning Overlap Parameters.

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