You are correct that soldermask properties can vary by the individual mask,
but some generalizations can be made about certain mask colors that I think
most PCB fabricators would agree with.  There can also be an interaction
with the surface finish - some are harsher than others when it comes to
attack on the soldermask.  For us, we have the same mask rules for green,
blue, and dark purple colors.  Red has slightly worse adhesion and requires
slightly wider webs, especially with ENIG finish.  Black is very
problematic, every fabricator I know will require wider webs with black
mask.

Morgan Viggers
Field Applications Engineer
ISU Petasys
503.675.3877


-----Original Message-----
From: Richard Hatano [mailto:[log in to unmask]] 
Sent: Monday, March 30, 2020 1:09 PM
To: [log in to unmask]
Subject: [TN] Solder mask properties associated with color

Hi,

I hope everyone is safe, practicing healthy habits and hopefully weathering
whatever obstacles are coming your way.

I had a question regarding the resolution of solder mask and how much it is
associated with particular colors.

My company tries to obtain various types of PCBs in different colors to help
with easy visual ID.
Unfortunately I get some feedback from the vendors that the solder mask will
not print correctly between fine pitch pads in blue and red so far.  I have
yet to hear problems with green.
I'd think those characteristics would vary more on the individual mask used
and not for it to apply based on colors.

I was hoping someone could post just a quick answer.
I'm usually trying to do 10 things at once (at least one of them well and
nine of them well-enough) or I would research it.
I don't expect anyone else to research it for me, but if you happen to know
I would greatly appreciate a brief comment.
Thank you very much and I hope you're all doing well.

Richard Hatano
EDA Manager
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3855 Ruffin Road, San Diego, CA 92123-1813  USA Direct  858-285-2392  |  Fax
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