[Elecraft] Interpreting Color Codes

[Ron D'Eau Claire]

Geoff, K6TFZ, wrote:
I have  noted by my own observations and comments of others some confusion
as to  exactly what colors are being observed on small parts, usually
resistors and RF chokes...Incandescent lighting seems to be the least
accurate for determining the correct colors, particularly yellows, oranges,
and browns. Many times I have used sunlight (if  available) or sought out a
fluorescent lamp (cool white with at least 5200K  temperature) to properly
interpret colors. When in doubt, I use a meter to confirm the value.

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Yes, reading color bands is a growing problem and lighting plays a huge
role, especially as the color bands are made narrower and narrower on tiny
parts. 

Incandescent light is very strong at the red end of the spectrum, making
reds more pronounced and blues look weaker. 

Fluorescents have gotten a lot better in recent years, but all I have seen
still have a discontinuous spectrum (some wavelengths where they produce no
light at all) and a huge peak in output in the green part of the color
spectrum. That can make gold look yellow, for example. 

The problem is that our eyesight has an automatic process that always
assumes the light we have is white, and all colors we see are adjusted
accordingly. When the source light is not uniformly "white", all the colors
we see are shifted accordingly.

Sunlight is ideal, but most of us build indoors and at night!  

I use a good magnifier to see the colors as clearly as possible and, if in
doubt, check the part under both fluorescent and incandescent light. I also
check a lot of resistors for value - especially the ones with blue bodies.
The body color further obscures the color of the bands. 

Inventorying is also an excellent idea. One can establish which part is
which by a process of elimination - matching up those that are obvious and
then sorting out what is left while referring to the parts list. If a color
is still in doubt, finding a known sample of the color often helps as I
suggested with chokes recently where a gold strip looked yellow. Comparing
that part with a similar part - especially with the same body color if
available - that has a known yellow stripe will often make the difference
clear. 

Ron AC7AC