[time-nuts] OT: Hewlett Packard paint codes

[Jack Hudler]

John,
	LOL, I was busy today doing just that!
	Took an image of the IT8/7 target, printed it, scanning it in and
then using a color 'curves' in PhotoShop to adjust the scanned image to the
correct RGB values. Did it in 2 passes and by god it worked spot on every
time.
	RGB values: base color 186,186,169  darker infill color 165,165,148
	But the interesting thing is this... the darker color is grey
difference of 21. 186-165 = 21 and 169-148 = 21.
	So I created a layer in PhotoShop with black for the darker overlays
and then set its Opacity to 21.
	Viola! You have this:
		http://www.hudler.org/pub/tn/6024Acolored.png
	and I print using this on an already painted background:
		http://www.hudler.org/pub/tn/6024Aprint.png
	This means that HP took the base color and added more lamp black.

	All this means is, you don't care about color values at all, just
the difference.
	Once you have the base color, the rest is all grey. 
	Well to be honest... it's not all grey... you got that dark brown
lot they fancied themselves on in the late 70's and 80's.

Thank you to the group for allowing me to stray far Off Topic!
Jack
	PS. Ditto on the GIMP comment.

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Neon John
Sent: Thursday, December 27, 2007 8:08 PM
To: Discussion of precise time and frequency measurement
Subject: SPAM-LOW: Re: [time-nuts] OT: Hewlett Packard paint codes

Jack, back to your original problem, the trick to hitting the color spot-on
after
only one or two tries is to use your scanner or even your digicam if you can
keep the
lighting exactly the same, is to use it as a comparator.  Scan the original
color and
save it.  Then generate output on your inkjet printer and scan that.  Look
at the
difference in each color channel and modify your original artwork color
accordingly.
Usually you can nail it after the second try.

This system doesn't rely on the accuracy of the monitor, printer or scanner,
but only
its repeatability.  Repeatability is usually excellent, at least until you
change
cartridges.

I haven't used this technique to duplicate colors on an instrument panel but
I have
used it extensively for conventional graphics arts where I need to match the
color on
a logo or whatnot.

RE: Gimp.  I wouldn't foist that crap off on my worst enemy.  Whomever
conceived that
user interface had to be stoned.  Bad stoned.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
If we aren't supposed to eat animals, why are they made with meat?