[Borek]

Borek  --   as always your are correct

I am known to be occasionally wrong

[ARGOS++]

Dear billnotgatez,  Dear Borek,

You all may think: What a stupid, jumping between such fronts!
But I’m only a “newbie” to this particular Forum, not else !!

Sorry billnotgatez,  that I’m toooo new in this Forum to have
already read Your posting about the Pigments. But You may have realised therefore,
that I usually answer a little “different” to most.
As a compensation I have figured out, that You are of the more seldom kind of
members of the Forums whit quite more then some experience!
As a maybe also experienced human (Sorry, I didn’t found out Your age.) —
You learned, as I, that every brain starts to solve problems with the tools he
knows best.
Sorry to Borek, is it not Why the old proverb tells in extremis:
    “If all you have is only a hammer, every thing looks like a nail”.
Of course, it may sound hard, but  - Do WE not all the same?
I’m assured, Borek was trying  to do it quite well, for You too.

Now to Your Pigment-Problem:
    As I have read Your Postings, and tried to filter out other answers,  I have identified it
    as a Pigment problem, but maybe not singular.
    (Could it be, that you are working for “Dyer” or/and “varnisher”?  I think.)
    I think too, from Your last post, that you were already knowing the half of your “own”
    answer before.
    I’m happy to tell You, that Your answer (A! kind! Of! spectrometer) is absolutely right, and
    ok ,  — BUT ….. .
    As I’m “married” since ~30 years with Dyestuffs, Pigments, Cloths, Lacquers,
    but also of same strength with Pharmaceuticals and Production of,  - allow me
    to direct two questions to You:
    A.) May I be right, that You in real are more interested in the “Shade/Strength”
         of the  “Printing on Cloth” as on the exact concentration of the pigment(s)?
    B.) Do You like, From A.), to destroy Cloths to estimate Your “liked”, if required,
         concentration?

If I know Your answers, You enable me to tell you what kind of spectrometer should
be prefered AND Why IT IS the most profitable for Your problem.
YES, but IF You don’t loose the eye for the follow-up costs, a hobbyist can fullfill a lot
of others, but not that (I'm a hobbyist, too).

So, I’m waiting for Your appreciated answer in THIS Forum, because
I think it is not made for only theoretical Analytics!

Good Luck!
                      ARGOS⁺⁺

P.S.:  billnotgatez,  You are absolutely right, about “cross posting”!
          BUT,  — Why should not “The Forum” do it for You AND Me, but mark it
                       as a “cross posting”!
                       Live could be much easier and more fun for both, with!

[AhmedEzatAlzawalaty]

thank u argoss u are the best

[billnotgatez]

I do have difficulty following your post but here is my response.

I have a paint that is without pigment to which I am adding metal powders.
The powders are aluminum and iron oxide.
A coat will have aluminum and another coat would have iron oxide.
I want to know the concentration of the metals in one square centimeter that is panted on cloth. There would be up to 4 coats with 3 coats could be aluminum pigmented and one coat of iron oxide pigmented. Let us assume that there are no impurities.
Later I would time the burn of the cloth that the sample was taken from and correlate the time versus concentration of pigment metals.

To do this I am going to build a device that can detect the concentration of a color.
This device is called a colorimeter.
http://en.wikipedia.org/wiki/Colorimeter
Although it might be less accurate than titration I think it will suffice for my project.

The question now remains what colors are involved.
Also I have to come up with the physical design and build it.
The former is harder for me than the latter.

Regards,
Bill

[ARGOS++]

Dear Bill,

Forgive me, that I implied from your earlier posts, You could be more
related to “dyeing” as it is in real,  —  my fault.
Even if you really do a manually painting, the process is called “dyeing”, only
not so “egal”/homogenius/uniform as mechanicly done.
Be assured, I know both Devices called “Colorimeter”, and that
a little bite better then “Wiki”.
YES, it's a “micro” little more complicate as “Wiki” can tell you, and more
correct, too! There are a Lot of faults inside, sorry!!

THE ONE  —  I can GUARANTY YOU —:  The “Wiki”-colorimeter (WC) will not
work for you, before You HAVE NOT DISSOLVED your WHOLE square
centimeter piece of cloth into an absolutely clear solution !!!! 
I think: For you a “mission impossible”!
That was exactly the reason why I was talking about spectrometer and
NOT about “colorimeters” like, OR unlike, WC.
WC’s can only measure in “Transmittance” AND NOT in “Reflectance” !!!!
Do you see the difference?  “Reflectance” is absolutely required to
measure Cloth, Lacquers, and other “Such a thing”.
Pigment is the “terminus technicus” for Dyes insoluble in water, like
your “Iron Oxide” or your “Aluminium powder”.
On the other side with one wavelength of a WC, but four unknowns,
you have to be really magic for any interpretation, isn’t it.

But Your Idea is still and for ever:  — Right and very close to the Best !!!
Also the spectrometer, several times called “Three-stimulus-Colorimeter” will
make you not happier, because its three values for each measurement are
mathematically not “enough” adequate to solve your problem, but to build such
needs already more knowledge as most hobbyist will give you.
What you need in this case is at least an, as cheep as possible, so
called “Color-Eye” and some Math. (I have done a Lot of such “recipes”)
Sorry that I’m not able to make it much simpler for you!
Maybe if you explain your, I hope not private, project to “X-Rite”, or other,
they will “rent” it to you for the short project time, for FREE.
But, please keep all time in mind, that “Reflectance” have not the same
high precision as “Transmittance” have !!! 
I think for your needs the precision should be satisfying.
Now the problem of calibration and the Math. is still remaining to US.

So, let’s “settle it down” , before WE do the next steps!
Good Luck!   —  till soon,  I still hope!
              ARGOS⁺⁺


P.S.:    Thank you Bill for being still here!!

[billnotgatez]

Sorry I did not make the protocol apparent.

I do not have the steps precisely but I will give an example to kick this off.

Cut a 1-cm square piece out of the cloth that has been painted with coats of paint that has been pigmented with metal powders and dried.

Put that square in a test tube with 5 ml of sodium hydroxide solution.
Leave it set overnight so that the cloth and paint are dissolved.
The metal powders will settle to the bottom.
Remove 4.5 ml of liquid with pipette
Refill with water and repeat removal 3 times
Put in chemical solution that will dissolve the aluminum and form a colored liquid
Colorimeter measure
Repeat the removal process of above
Put in chemical solution that will dissolve the iron oxide and form a colored liquid
Colorimeter measure


PS – titration is looking better hmmmm


you might be right about mission impossible

[Ψ×Ψ]

Not sure how you'd go about making it, but iron makes a nice coloured complex with phenanthroline that I've used for colorimetric measurements before.
I really don't know how you'd go about colorimetry with aluminum, though.  The only aluminum complex I remember as being brightly coloured was a red lake that I came across in gen chem lab many, many years ago.  Unfortunately...you might have a solubility issue there.
(Trying to be helpful, but I'm not really so friendly with metals.)

[ARGOS++]

Dear Bill,

( Sorry, to have not been present the few last days, because I have
  sometimes something to do for my private customers, too)

I’m not sure you have seen it by yourself, that with your last
posting you have re-shuffled a little bit the card-game.

The procedure you describe looks not very reliable on one side and on
the other I have certain troubles to believe, that you will have cloth of
such a special kind.

But let me answer from the stirrup, as I have not very much time for, but
I'm pretty sure I know the answers you need:
 A.)  The Very, very start looks ok, but what goes in solution with the
        sodium hydroxide is the Aluminium and not the Iron Oxide.
        Metallic Aluminium gives with sodium hydroxide a very exothermic
        Reaction, but not a solution by itself.
        To build the real solution you must:
         a.) Use Strong  sodium hydroxide (high concentrated) and
         b.) Heat it for a certain while to build Al[O₃]^3- as quantitative as possible,
              which is soluble inside an excess of OH^-.
 B.)  The “Likelihood” that you will have a cloth that is such easy to dissolve in
        sodium hydroxide can not be believed, but dose not interfere the
        “quantitative” Determination of Aluminium.
        If you have the possibility to get a small glass-funnel with sintered disc
        (Nr. 5 should already do it, otherwise Nr. 6; Ø = ~2cm) it will be the
        much better choice as Decantation, and faster all the time too.
        Filter it directly into a Volumetric-Flask and wash with fresh sodium
        hydroxide solution; NOT with water !!!! (Why?).
 C.)   In the Volumetric-Flask you can prepare a Complex with Alizarin to be
        measured with a “”Colorimeter"”, maybe around ~500nm - 530nm in
        relation to a Standards. Lambda_max for Alizarin as I remember is 435nm.
        The required recipe you will find at least in Complex Chemistry Books.
        Keep care that you may have to measure NOT on Lambda_max to protect
        your result as good as possible from other present Me-Complexes.
 D.)   Set your glass-funnel on the top of fresh Volumetric-Flask.
        Cover the on the sintered disc remaining cloth and Iron Oxide several times
        with always a small amount of “Aqua regia” for some time, and wash the
        build Solution through the disc with small amount of dest.water.
        As more fresh the “Aqua regia” is build as less repetition you have to do.
        You can easily control it by Eye!
        For your surprise, now most of your used cloth may also disappier.
 E.)   Thank you ?*? very much, Your posting covers one of the good,
        adequate Method for quantitative determination of Iron.
        I don’t know the Lambda_max but maybe ?*? can inform you about.
        The only other often used Complex for this task I know, without consulting
        any book, is the Acety-Salicillic-Acid-Complex with a Lambda_max
        close to  ~540nm.
        To build the Complexes, there are Standard-method written elsewhere,
        BUT keep in mind, that you have FIRST to destroy the still
        remaining but unused oxidative power of “Aqua regia”

This whole procedure is adapted for conventional “Colorimeters” where
you are quite easier able to change the wavelength.
But with home-made “Colorimeters” you will mostly miss this feature, and that
means as a consequence you will miss a Lot of selectivity.
So, Please take care for!
Home-made “Colorimeters” mostly use a colour LED as a selective source
of Light, but then you are very limited.
I remember, that once a KIT was/”maybe still is” available with a Foil, to have
much better options for wavelength selection.
As for Titration you have to do anyway most of the procedure, AND additional
preparations to be able for the reliable Titration, it could be easily possible that
your Colorimetric is simpler to handle.

Please, as I had to do it in a hurry from the stirrup, validate all information,
before you start.

I hope it maybe anyway of help to you.
Good Luck!
                    ARGOS⁺⁺

P.S.:  Please keep in mind, that in the moment I have not so much
         time to answer Questions as till jet!  Sorry.

[billnotgatez]

The sodium hydroxide step at the beginning was to dissolve the organic material at the beginning. This would include the 100% cotton cloth as well as the doping paint. Thus we would leave behind the aluminum and iron oxide particles. everything would be liquid at that point except the metal solids of iron oxide and aluminum.

[billnotgatez]

Thank you
?*?
ARGOS++
Borek

For responding