This question concerns graphic design and the proper use of a specific
international symbol (pictograms).  There are two parts to the
question:  1) There are currently two different symbols being used to
indicate "information"  (ie, "the international information symbol")
-- you might see this symbol used on a sign at an airport, or along a
highway to tell drivers that information is available.  One symbol is
a question mark usually set in a blue circle or a blue rounded-corner
square.  The other is an italic letter "i", set as a white letter
inside a blue square.  Which one of these is most proper to use?   
The second part of the question is:  What is the correct blue to use? 
Is there a color specification or RGB formula so that graphic
designers can produce the symbol properly?  Thank you.

This was a very tricky and impossible task (for me anyway!)

I think the document you need is "ISO 7001:1990   Public information symbols"
http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=13565&ICS1=1&ICS2=80&ICS3=10

It costs 150 Swiss francs.

Also see:

"ISO 7001, ?Graphical symbols for use on public information signs,? is
a set of international symbols based on the ?ISOTYPE? system of icons
and pictograms introduced by Otto Neurath in the 1936. However, soon
after the 7001 was published, it was determined that the standard
international symbols did not have a standard meaning or clarity in
every country. Published in 1989 and revised in 2001, ISO 9186 is a
procedure for user testing of graphic symbols to determine which
symbols communicate the intended meaning most readily to most people.
There are two main test methods: a comprehensibility judgment test and
a comprehension test. [source] Pictograms with exceptionally high
comprehensibility in several countries can eventually become part of
the ISO 7001 set."
http://www.backspace.com/notes/2003/06/24/x.html

Or it could be:
"BS 8501:2002 Graphical symbols and signs. Public information symbols"
http://bsonline.techindex.co.uk/BSI2/Dir1/SitePage.asp?LS=&PgID=0080&LR=&LD=&Src=&Dest=&Last=&SessID=CSLM8BTHUUCE9LW54NPX8PELR16AAL67&MSCSID=&ErrID=&SessStat=&Parent=&Child=&PCount=0&LogStat=&URLData=&SEARCH_ID=4357AB091BSM8MEWVB7M2CSJFD89AVJ1&SEARCH_TYPE=SRCH_TYP_QCK
 

Either way, good luck!

THX1138