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Property Name



This property defines whether or not an event is transparent to busy time searches.

Value Type


Property Parameters

IANA and non-standard property parameters can be specified on this property.


This property can be specified once in a "VEVENT" calendar component.


Time Transparency is the characteristic of an event that determines whether it appears to consume time on a calendar. Events that consume actual time for the individual or resource associated with the calendar SHOULD be recorded as OPAQUE, allowing them to be detected by free/busy time searches. Other events, which do not take up the individual's (or resource's) time SHOULD be recorded as TRANSPARENT, making them invisible to free/ busy time searches.

Format Definition

This property is defined by the following notation:

 transp     = "TRANSP" transparam ":" transvalue CRLF

 transparam = *(";" other-param)

 transvalue = "OPAQUE"
             ;Blocks or opaque on busy time searches.
             / "TRANSPARENT"
             ;Transparent on busy time searches.
 ;Default value is OPAQUE
Example:  The following is an example of this property for an event
that is transparent or does not block on free/busy time searches:


The following is an example of this property for an event that is opaque or blocks on free/busy time searches:


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