ok, cool, now that we have that settled, why is the silkscreen white?!!
hmmm...









At 02:59 PM 6/15/99 -0500, you wrote:
>DC Members,
>    I talked to a couple of retired experts (my brothers )  and this is what
>they had to say....
>
>First my brother John:
>
>My theory is that the color green preserves the solder coating on the
>board from breaking down, a lot like the color brown on beer bottles
>keeps the beer fresh.  I could give you a long theory to go along with
>that, but I need to delve into the color brown right now.
>
>and from my brother Joe:
>(p.s. shows where the brain in the family is....)
>
>I thought that everyone knew the answer to this question.
>
>The green color of soldermask was chosen after extensive testing by the U.S.
>military at the National Materials and Procurement Center in Cedar Bluffs
>Virginia in late 1954. According to Colonel Robert Bright, Public Liason
>Officer, the particular shade of green was found to provide the maximum
>contrast to the white silkscreen ink under all tested adverse situations
>while still allowing a clear view of the underlying circuitry. Every other
>color tested failed to provide the required contrast under conditions of low
>/ high illumination levels and various colored light sources.
>
>The quantity of Printed Circuit Boards purchased by the Defense Department
>established a "de facto" standard which most vendors began to follow. Usage
>of other colors is permitted for prototype and or pre-release boards.
>
>Hope this clears this matter up.
>
>: )
>
>Karl
>
>Attachment Converted: "e:\internet\mail_ultra\attach\karlbates.vcf"
>

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################