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Crafts

copper smelting

metal transmutation

copper patinas

verdigris

liver of sulfur

metal pigments

carmine

frescoes I

frescoes II

binders

perkin's purple

spectroscopy

color workshop

microscopy


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alchemical symbols

 

 

 

 

 

 

 

 

 

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The Crafts section is where procedures, instructions and information for each week's studiolab are located.


Cu symbols

Copper smelting

Step 1.  Roasting Malachite to copper oxide
                  Identify a smelting partner for this process. Each of you take 2 malachite chip beads (2 beads per student) and place them in a porcelain crucible.  When working with the beads, it is recommended to use a weighing boat to hold the beads which easily roll away.  The crucible is covered with a lid and placed in a triangle on a ring stand.  Using a Bunsen burner roast the sample for 15 min.  The inner blue cone of the Bunsen flame should be touching the bottom of the crucible.  After this period the heat is removed and the crucible is allowed to cool for 10 minutes. 

Step 2.  Reduction of copper oxide to copper metal
                  A charcoal briquette is placed into a folded paper towel and finely crushed with a hammer or mallet or other heavy tool.  The crucible is filled with crushed charcoal to within ¼ in of the top and tapped gently to settle the contents.  The crucible is covered and heated on the Bunsen burner for 90 minutes.  After this period the heat is removed and the crucible is allowed to cool, covered.  The excess charcoal is removed and the copper metal isolated.  If the sample appears red and chalky, it has not been fully reduced and should be allowed to react longer. 

 

alchemical header

metal transmutation

First, take ye a piece of . Clean and polish her well so her rosy cheeks shine.
Now with ye friend, search out a fine pot. Place in it one spoon of
Fill to half the pot with . Apply a good to make his spirits bubble.
With all care and right tool, place her into the spirited waters.... Watch ye well.
See how the spirits increase and come rightly from her. See her thus change to new.
When the spirits have quieted then disappear, with right tool, remove her from the pot to cool then wash her well to keep her pure.
Now has the glorious moment come! When the cherished One from fire is yielded.
With tool again lift her new and changed and put her into the fire of tranformation.
That which is most pure, of many names, and now is formed.

(Roll cursor over alchemical symbols to see modern names)


Method One:

Grind together equal masses of zinc chloride and copper sulfate with enough water to make a paste. Brush a layer of paste on a freshly cleaned piece of copper. Allow the paste to dry. Then rinse off the paste and place the copper in strong sunlight (or alternative light source if it is a cloudy day). Observe and note the color of the metal surface.

 

Method Two:

Using a brush or cotton swab, apply Potion A to a piece of clean, polished copper metal or wire. Allow the solution to dry and observe the change in metal surface. You may re-apply more solution to increase the patina layer thickness.


verdigris

Obtain a jar and a petri dish that will fit inside the jar. (see example in lab). Using a disposible pipette, place enough glacial acetic acid to cover the bottom of the jar to about 1/8 inch, carefully avoiding dropping any acid into the small petri dish. Using the metal snips, cut a piece of copper sheet that is about 30 x 50 mm (1" x 1.5") or a size that will complete fit in the inside petri dish. Clean the copper using the metal polish provided. Wipe the residue carefully and polish until the metal is a rosy copper color. Carefully place the piece of copper metal on the small petri dish (as shown in example). Securely tighten the cap on the jar and set the jar in a designated spot in the hood.


LIVER of SULFUR

A. To recreate hell in the laboratory, put two parts sulfur in a small beaker, layer on top of the sulfur one part quicklime (calcium oxide), and then add on top of the solids 6 parts water. Heat the mixture on a hotplate and observe closely. With your partner, construct your own allegorical interpretation of the reaction.

(note; you may need to stir floating solids back down using a glass stirring rod.)

B. The red solution is another chemical mixture useful for coloring copper metal, i.e., producing a surface patina. Try this: take a piece of copper metal, clean it well as you did last week, and dip it into the solution. A few seconds is all you need. Another interesting method is to dip a paintbrush into the "fiery hellish solution" and draw a design on the copper.


Syntheses of Four (Transition) Metal Pigments

using Chromium (Cr), Copper (Cu) and Iron (Fe)

. Chrome Yellow.

Glassware needed: 1) 100 mL beaker, 2) small (10 mL) graduated cylinder, 3) buchner funnel, 4) filter flask

Measure 5mL potassium chromate solution using the graduated cylinder and transfer (pour) the solution to the beaker. Rinse the cylinder well with distilled water, then measure 5 mL of zinc chloride solution. Add the zinc chloride to the beaker. Stir with a glass rod. Using a disposible pipette, add 10 drops of sodium hydroxide. Note carefully all changes you observe. Isolate the chrome yellow pigment using a Buchner funnel, filter paper and filter flask. Rinse the pigment with water and allow to dry on the filter paper.

.Viridan.

Glassware needed: 1) mortar and pestle, 2) small crucible, 3) triangular wire support . 4) 150 mL beaker, 5) buchner funnel, 6) filter flask

Obtain a mortar and pestle. Place into the mortar 3 g of sodium dichromate and 0.45 g of sulfur. (Weigh out the needed amount of each solid on a plastic "weighing boat".) Grind the two solids together until they are a fine powder. Transfer this powder to a small porcelain crucible using "glassine" or weighing paper. Set the crucible on a trianular wire support. Following the instructions of your instructor, heat the crucible in a flame from a bunsen burner until no further gas or smoke is produced. Allow the crucible to cool. When you can safely handle the crucible with your hands, scrape out the solid product and put it back into a **CLEAN** mortar and pestle. Grind it again then transfer it to a medium sized beaker (150 mL) being sure to remove all tehpowder by wahsing (rinsing) the mortar with water. Fill the beaker with water approximately halfway and stir vigorously. This process is dissolving ( "extracting") into the water any undissolved reagents (what, if any, color(s) do you observe?). The green chromium pigment will be left undissolved in the beaker. A Buchner funnel, filter paper and filter flask are used to isolate the pigment. Rinse the pigment with acetone to help remove water and speed drying.

.Prussian Blue. Glassware needed: 1) 2 small beakers, 2) glass funnel

Weigh 0.410 g of iron(III) chloride [Fe(III)Cl3]in a weighing boat. Weigh 0.470 g of potasssium ferrocyanide [K4Fe(CN)6] in another weight boat. Carefully add one or two pipettes of water to dissolve each solid separately in the weigh boat, then also carefully pour each solution into a beaker. if not all teh solid has dissolved, stir with a glass rod. Now, add the solution of Fe(III)Cl3 dropwise (using a pipette) to the K4Fe(CN)6 solution. What happens?! Stir briefly the allow the mixture to sit about 10 minutes. Place teh glass funnel into a ring-clamp on a ringstand. Place a beaker 9 any size) under the funnel. Flute filter paper and plae it in the funnel. Finally pour and scrape the prussiun blue pigment formed into a fluted filter paper in a glass funnel. Allow the thick mixture to slowly drain the excess solution away down the funnel. Leave the pigment on the filter paper ad place it on several paper towels (labelled) to dry over the next week.

.Verdigris (harvesting).

Remove your verdigris-coated copper plate or pipe from the petri dish or jar and place it on the inverted petri dish top. Allow the verdigris to "dry"; it will become paler and powdery in appearance. Scrape the verdigris off onto a piece of glassine (or weighing) paper. Store the verdigris in a vial and label it .

 


Carmine from Cochineal

Carmine is a natural dye substance that comes from the crushed bodies of insects, Dactylopius coccus, found on prickly pear cacti. Cochineal can be used with or without mordants and produces coral orange, reds, pinks and purples


1. Crush and grind the cochineal into a fine powder using a mortar and pestle.
2. Place the ground cochineal into a small glass jar and cover with distilled water.
Add tartaric acid to the cochineal/water mixture to release more of the colour.
Let the cochineal mixture sit at least overnight.
3. The following day, fill a beaker with hot water, sufficient to cover the item to be dyed.
4. Bring the water to a boil and add the cochineal mixture.
5. Boil for 15 minutes, and skim off the froth and cochineal that has risen to the surface. The cochineal can be dried and reused.
6. Add the clean, wet fibre or yarn to the dyebath.
7. Let the dyebath simmer for 35 - 40 minutes.
Remove item from dyebath, rinse in warm water and dry.

Tips:
Most Important!! Only distilled water should be used; tap water contains metal cations that will alter the color.

I have read that:

-Cochineal with no mordant gives pinks/magenta.
-Cochineal with tin mordant yields reds/oranges.
-An ammonia afterbath will result in purples.

however, in my own experience these colors and mordants don't necessarily correlate (!). We'll have to experiment!

 


..the method - you will prepare a plaster surface on the unglazed side of a ceramic tile. while the plaster is till fresh (fresco), you will paint a design of your choice using pigments prepared in water. you may use pigments you have synthesized or pigments from Kremer, the best known supplier of artists' pigments. you should paint two tiles, one to keep and one to "destroy". next week we will investigate the conditions that lead to fresco deterioration. there are various sizes of tiles available. it is advised that you use the smallest tiles for the deterioration tests.

..preparation of the tiles - variously sized tiles have been soaked in water for more than 24 hours and are ready for receiving the plaster—intonacco—layer.

..preparation of the plaster - you should prepare the plaster with another student, in pairs. mix one part sand and one part pit lime in the plastic tubs. you may use a spatula or a hand in a protective plastic glove. mix the two components well until homogeneous and pliable.

..apply the intonacco layer - remove a tile from the water bath and allow it to drain and dry slightly until the unglazed surface acquires a matte surface. apply the plaster with a spatula or scoopula, spreading it to make a thin layer (about 1/8 - 1/4 inch thick). a layer that is too thick will crack on drying. smooth the surface using the curved side of a scoopula, passing over the surface in one direction then again at a right angle to the first pass.

..painting the design - you should think in advance of how you wish to paint yoru design. you can paint freehand or, you can transfer a pre-drawn design by "pouncing" or tracing. pouncing involves making your design, punching holes that will define the lines of yoru design, then :pouncing" dry pigment through the holes to outline the desine on the fresco. tracing can be done using a pencil or blunt object to trace over the lines of the design, slightly scoring the surface of the plaster beneath the design on paper.

the plaster must evaporate much of the excesss water before applying the paint. it is ready for painting when a brush loaded with clean water is passed over the plaster and does not score it and the plaster absorbs the water. the drying time prior to painting can take 10-20 minutes, depending on the humidity of the room and the moisture in the plaster.

while waiting for the plaster to dry, you can continue to plan and prepare your pigments. pigment ay need to be ground—"mulled"—with water in a mortar and pestle to make a pigment /water suspension. there is also a glass muller and polished marble plate for you to try mulling pigment. the paint is ready when a drop in a vial of water floats (mostly). the paint should be applied as a rather dilute wash, rather than a thick paste. one method of accomplishing shading and shadow effects is to first paint the darker portions representating shoadow, then paint a wash of the lighter color on top of the shadow. the paints will be transparent and require several coats for intense colors. allow ~15 minutes between coats.

..note!! - some pigments are chemically incompatible with the very alkaline medium of the plaster. prussian blue in particular will change color over a week and fade from blue to dull green. good choices for long term stability are any ochres, ultramarine. carmine lake is likely to fade as well.

..fated for destruction - on the small tile whose fate is to be less than beautiful, be sure to include lead white, ultramarine, azurite, malachite and verdigris pigments in your painting


For this studiolab you will do the following:

- use lead white, azurite, verdigris and malachite to paint a small watercolor. This watercolor will be placed in a small plastic bag with sodim sulfide solution.

- make observations about the putting small amount of the follow salts in solutions:

  • sodium carbonate
  • barium chloride
  • barium chloride added to an already prepared solution of sodium carbonate

- chip off an edge piece of your fresco and place it in hydrochloric acid. Do the same with a piece of marble.

- depending on the pigments in your small fresco, you will place it in a plastic bag with an acid or with sodium sulfide.

Details for doing the above tests will be given in lab.

** It is very important to make careful observations this week and note them in your notebook.


This studiolab is devoted to your exploration of five different media—acrylic, oil, tempera, watercolor and pastel. In order to work with all five binder media, and especially if you wish to create your own art using one or more of these media, it is essential that you arrive prepared and with a plan. Read the following instructions carefully.

At each of the four benches in the lab will be the materials to prepare one type of binder. As detailed below, you will either prepare the binder mixture alone for your individual use or, your group at the bench will prepare enough binder for all the group to use to mix paints. The procedure for making each type of binder media and paint is described below.

Acrylic. Do this individually. Three types of acrylic polymer binder are available. One dries to a gloss finish and the other dries to a matte finish. Obtain about 5 of each acrylic polymer suspension in a small plastic cup. Note its characteristic odor, color and viscosity.

Oil. Do this individually

1. Combine 4 mL of linseed oil with 8 mL of turpentine in a paper cup. Stir well. **There is also walnut oil an dsafflower oil if you wish to see how oil paint from these oils differs.**
2. Describe the color, texture and viscosity of the binder.

Tempera. Do this in individually.

1. Obtain one egg. Separate the egg yolk from the white. Discard the egg white in the sink. Place the yolk in your palm and pass it from one palm to another until the yolk sac becomes fairly dry. Puncture the yolk and drain it into a small lastic cup.
2. Add an equal volume of distilled water to the yolk. Stir the mixture into a pale colored emulsion.
3. Describe the color, texture and viscosity of the binder.

[Note: here are other recipes for tempera, in case you want to experiment more with these later.]

Watercolor. Do this as a group.

1.Place about 4 mL (1 teaspoon) of water in a small plastic cup, add about 4 g (1 teaspoon) of table sugar and stir to dissolve.
2. Stir in 6 mL of glycerol (glycerin) and 20 mL of the previously prepared gum Arabic stock solution. Add 1 drop of a lab detergent (soap) and mix well.
3. Describe the color, texture and viscosity of the binder.
Save and label this to conserve the watercolor binder for use by other groups.

Making the Paints. The pigments, especially those you synthesized several weeks ago, need to be crushed and finely ground before mixing with the binder. Use porcelain mortar and pestles for grinding, and please re-use mortars already stained with a particular pigment (like prussian blue). Place a small pile of pigment on glassine paper and add 5-10 drops of binder then mix with a spatula, repeatedly rubbing the pigment/binder paste with spatula to ensure even coating of the pigments particules by the binder. For acrylic paint, first mix the pigment with water, then add the acrylic binder. This serves to aid dispersion of the acrylic media around teh pigment particules.

Which pigments to use in making paints? You are free to use any pigments available in the lab as well as those you synthesized. It is recommended that you make paints using all four types of binders with a set of the same 2-3 pigments ( for example Prussian blue, chrome yellow, viridian and ultramarine) to see the differences in paint appearance and behavior in the different media. You may make up additional paint colors and create a painting as time allows. An efficientcy tip: grind up enough pigment to be used in all four binders.

Pastel. Do this as a group.

Making pastel sticks involves trial and error in order to obtain the desired properties. Getting a good pastel stick involves mixing just the right amount of binder and pigment. This is where the experimentation comes in. This is because different types of pigments need different strengths of binder for optimum working properties of the pastels.
The first step in making the pastels is to prepare a dilution of the stock gum Arabic binder.

Preparations of Gum Arabic Binder Solution

1. Obtain a plastic cup. Measure out 10 mL of gum Arabic stock solution into one of the cups.
2. Add 20 mL of water to this solution. Mix well. Save and label this to conserve the gum binder for use by other groups.

Procedure for Making Pastels
1. Place about 1-2 teaspoons each of pigment and Kaolin on a clean non-porous surface (wax paper). Mix them together.
2. Add a small amount of the diluted gum Arabic binder, a few drops at a time, to make a doughy consistency.
3. Work the pigment and binder together with a spatula until the mixture has a rubbery consistency. If it is too wet it sticks to paper and if it's too dry it will fall apart. If you add too much liquid you can add a bit more pigment and Kaolin mix.
4. Roll the dough on paper until it is the shape you want. Allow the sticks to dry for a day or two before use.


Synthesis of Perkin's Purple Dye Mauveine

see handout for procedures


Measuring Color: Spectroscopy

Objectives for today:

Understand:
1. what is spectroscopy
2. how it quantifies color
3. what is meant by light absorption, reflectance, transmittance
4. how to generate a reflectance ( transmittance) spectrum from an absorption spectrum and vis versa.
5. how broadly spectroscopy can be applied, e.g., how infrared spectroscopy is possible.

Lab
1. run at least one visible spectrum of purple and plot as absorbance and as transmittance
2. options:
1) run (with help) an infrared spectrum of phthalocyanine; 2) run visible of different watercolors
3. Clean-up lab


What pigment was used?

the goal: Identify what pigments are in my painting

the method: Microscopy
a) identifying isotropic vs. anisotropic pigments
b) chemical reactions


the strategy: Get familiar with microscope.

To start:

a) Look at NaCl (isotropic) then cross polarizers. (put few crystals in smear of oil to fix)
b) Look at (TEA)2MoS4 : anisotropic: see what happens under crossed polarizers
c) Look at azurite: anisotropic.
d) Look at ultramarine: isotropic

Test chemical reactions:

a) Azurite and HCl
b) Prussian blue and NaOH
c) Ultramarine and HCl
d) Cobalt blue and either

Plan your strategy.

a) Mark location of sample on copy of picture.
b) Take at most 2 samples. Use knife; have slide ready with oil smear
c) Place "authentic sample" on slide too for comparison.