Re: "Colorimeter"

On 5/21/2025 6:19 AM, Liz Tuddenham wrote:

Don Y <blockedofcourse@foo.invalid> wrote:
 

Sampling jitter within a window corresponds to spectral resolution;
the more jitter, the wider the range of wavelengths potentially
involved in the sample (over time).  As sampling the detector
is a discrete time event (the interval between samples being the
width of the window), how frequently you do this further defines
the spectral resolution.

 I was assuming very fast sampling so that the presentation of each line
was captured by many samples, that way the software could sort it out
over a large number of repeated passes.  Keep the hardware simple and
let the software deal with the errors if it can be given enough data to
start with.

Are you expecting to frequently sample the entire spectrum in each
"pass" ("revolution")?  Or, walk the sampling window up/down the spectrum
in stages?
I.e., how much time are you expecting to spend PROCESSING the sampled
data vs. acquiring more data?

Less developed software, lower sampling rate, slower ADC and less memory
in the cheaper version.  (And a garish box with "Professional" on it, to
let customers know that this is the cheap and nasty version.)
 [...]

"Cheap and cheerful" is a slang [UK English] expression meaning  a quick
rough estimate or goods that aren't intended for serious long-term use.

>
"Quick and dirty", "spit and baling wire", "bubble gum and shoe strings",
"good enough for government work", "mickey-mouse", "jury-rigged",
"jerry-built", etc.

 That's the sort of thing.  An interesting demonstration toy, rather than
a laboratory instrument.

None of the above imply a "toy".  Rather, just not spending much
resources trying to dot every I and cross every T.
E.g., as presented to me, there was no need for calibration against
a reference standard, "flat" response across the spectrum, etc.
A "laboratory grade" device likely WOULD impose such specifications.
And, bear an associated (likely high) cost.
E.g., one of the activities at one of my "summer jobs" (college) was
in testing hand tools.  Which ISO standard defines the specifications
for a "hammer" (WHICH type of hammer?)?  How can you get the specifications
of a particular "hammer" so that you can compare model A to model B,
manufacturer X to manufacturer Y?
Yet, you know that "hammers" have to be tested -- if only to ensure the
"process" isn't deviating from expected norms.
And, once you have devised a suitable test (in whatever bogounits seem
appropriate), you can then sample your competitors' wares to see
how you stand up.
None of this being of direct interest to the consumer as the units are
likely not anything that the consumer can relate to directly.  It can,
however, tell you how much you can improve or cost-cut your product
(and process) without risking your product looking inferior to those
of your competitors.
This is far more common than "laboratory type specifications" in many
industries.  (as engineers, we often fixate on numbers that have little
practical meaning)
How *hard* should the aspirins you take be?  Would a larger/thinner dosing
form be "better" -- for the consumer, absorption, manufacture?  "Gee,
why is this pill so much smaller yet claims to be the same STRENGTH as
the larger/heavier ones I was taking?"