Which Binder is Best to Create Pastels?

Holly Kratzer

Student Projects, Pigments/Dyes/Binders

Introduction

The purpose of this project was to identify whether expensive [inexpensive? ed.] household products would prove to be successful binders in comparison with a more expensive product made for the purpose of a binder for pigments. Products such as oats, honey, gelatin, water, and Gum Arabic were each combined with three different pigments, red ochre, yellow ochre, and smalt, to create fifteen different pastel crayons. Though the crayons were more difficult to make than what I had originally believed, my project appears to have successfully achieved its purpose. By creating drawings with each of the pastel crayons, evaluating the crayon's quality, and evaluating the results of a colorimeter, I determined which binders should be used and which binders produced crayons of poor quality.

Background

My project was inspired by the artists Edgar Degas, Mary Cassett, and Henri de Toulouse-Lautrec and their love of pastels. Though impressionists are often regarded as the main sources for pastel paintings and sketches, the medium was first used in the 16th century by Johaim Thiele. The Pastel Society of America explains the qualities of pastels as "Pastel does not at all refer to pale colors, as the word is commonly used in cosmetic and fashion terminology. The name Pastel comes from the French word "pastiche" because the pure, powdered pigment is ground into a paste, with a small amount of gum binder, and then rolled into sticks. The infinite variety of colors in the Pastel palette ranges from soft and subtle to bold and brilliant." Due to the versatility of pastels, artists from the 16th century to present day have taken advantage of the beautiful images the medium creates. (Connecticut Pastel Society)

Procedure

Materials Needed:

*Water

*Honey

*Gelatin

*Oats

*Gum Arabic

*Red Ochre (powder pigment)

*Yellow Ochre (powder pigment)

*Smalt (powder pigment)

*Mixing Knife

*Square Mirror

*Scraping Tool (cardboard strips)

*Glass Dishes for Storage

*Three Strips of Paper

*Colorimeter

1) The Procedure for creating pastels with each of the pigments and binders was similar, but each took a trial and error approach:

Honey and Gum Arabic: I first placed the yellow ochre pigment on a flat piece of glass, a square mirror in this case. Making sure the pigment was completely ground, I added enough water to saturate the pigment, using the mixing knife until the pigment was of a thick, liquid consistency. I then added several drops of honey, once again using the mixing knife, until the mixture appeared of a thicker consistency. As the honey transformed the pigment and water mixture into a thicker material, I realized that I would still not be able to handle the material with my hands until the consistency was almost solid. More pigment was then added until the mixture appeared durable enough for handling. I then rolled the mixture into sticks with my hands and left the pastel to dry uncovered on a glass dish. The process was then continued with red ochre and smalt until satisfactory pastel crayons were created. As the Gum Arabic has the same consistency as honey, I used the same method to create pastel crayons with the three varieties of pigments.

Oats and Gelatin: The production of pastels with dry ingredients, such as these materials, proved much easier than the binders of a liquid consistency. I once again placed the pigment of ochre yellow onto the flat mirror and added water. However, I added more water than with the previous pastels because I knew that the oats and gelatin would absorb much more of the liquid. After adding water until the pigment was a thin consistency, I added the oats. Using the mixing knife, I mixed the ingredients until the mixture was of a thick, manageable consistency. One again, using my hands, I rolled the mixture and placed it to dry in a glass dish, uncovered. The process was continued with each of the pigments and then with using the gelatin as a binder.

Water: I understood that in order to asses the effects that the binder had upon the color of the pastel, I needed to create crayons with only water and the pigment. The process was similar to the other binders as the pigment was poured onto the mirror. Though water was added to the above pigments also, this time the water was added in small amounts since no other binder would be used. I had to use a trial and error process of adding water and then pigments until a thick consistency was created. As with the other pastels, the mixture was then rolled into sticks and left to dry on an uncovered glass dish.

 

2) Evaluating the effectiveness of each binder

After each pastel crayon had dried sufficiently, I gathered three strips of paper to create drawings. Using one pigment for each sheet of paper, I covered a large area with the pastel so that the quality of each binder could be easily compared. The colorimeter was then used on each combination of pigment and binder and the values recorded.

Observations and Data

Observations of Pastel Crayons (Appearance and Drawing Ability):

  Yellow Ochre Red Ochre Smalt
Oats

*Easily breaks

*Rough surface

*Very easy to draw with

*Easily breaks

*Rough surface

*Very easy to draw with

*Easily breaks

*Rough surface

*Difficult to draw with

Honey

*Durable

*Crayon us very textured

*Easy to draw with

*Breaks easily

*Smooth surface

*Easy to draw with

*Breaks easily

*Smooth surface

*Difficult to draw with

Gelatin

*Hard and durable

*Very grainy surface

*Difficult to draw with because too grainy

*Hard and durable

*Very grainy surface

*Easy to draw with

*Hard and durable

*Very grainy surface

*Almost impossible to draw with because too grainy

Gum Arabic

*Very hard, brittle

*Smooth surface

*Too hard to draw with surface (crayon had to be broken)

*Very hard, brittle

*Smooth surface

*Too hard to draw with surface (crayon had to be broken)

*Very hard, brittle

*Grainy surface

*Too hard to draw with surface (crayon had to be broken

 

Water

*Breaks very easily

*Difficult to draw with because of fragility

 

*Breaks very easily

*Difficult to draw with because it broke very quickly

 

*Broke immediately

*Impossible to draw with, had to use powder to smear onto paper

 

 

 

Appearance of each Drawing:

  Yellow Ochre Red Ochre Smalt
Oats

*Very smooth

*Even color on surface

*Deep yellow color

*Easily smears

*Very smooth

*Even color on surface

*Deep red color

*Easily smears

*Rough areas in the drawing

*Uneven color (traces of black and blue

*Very light shade of blue

*Does not smear

 

Honey

*Smooth surface

*Even color on surface

*Very deep yellow color

*Smears very easily

*Smooth surface

*Uneven color (more traces of the paper can be seen)

*Deep red

Easily smears

*Rough surface, grainy like

*Uneven color (darker in some areas)

*Light shade of blue

Does not smear

Gelatin

*Smooth surface

*Even color on surface

*Lightest yellow shade

*Smears easily

*Smooth surface

*Even color on surface

*Dull shade of red

*Smears easily

*Shade of blue can barely be seen
Gum Arabic

*Smooth surface

*Uneven color (more of the paper can be seen)

*Very dark yellow shade

*Smears easily

*Smooth surface

*Very uneven color (lots of the paper can be seen)

*red shade

*Smears easily

*Smooth surface

*Color appears more even than other blue shades

*Light blue shade

*Does not smear easily

Water

*Smooth surface

*Uneven color (some places are darker than others)

*Deep yellow shade

*Smears easily

*Smooth surface

*Most even amount of color

*Deepest shade

*Smears easily

*Smooth surface

*Even amounts of colors

*Light blue shade

*Does not smear easily

 

Colorimeter Results:

  Yellow Ochre & Oats Yellow Ochre & Honey Yellow Ochre &Gelatin Yellow Ochre & Gum Arabic Yellow Ochre & Water
L* Values 68.68 70.00 86.77 70.06 65.22
a* Values +10.24 +5.96 -0.09 +7.88 +9.56
b* Values +55.26 +50.56 +30.66 +43.10 +46.46

 

  Red Ochre & Oats Red Ochre & Honey Red Ochre & Gelatin Red Ochre & Gum Arabic Red Ochre & Water
L* Values 36.81 40.83 39.01 52.94 38.53
a* Values +28.34 +26.14 +29.00 +18.77 +31.23
b* Values +17.73 +15.36 +18.67 +10.93 +20.27

 

  Smalt & Oats Smalt & Honey Smalt & Gelatin Smalt & Gum Arabic Smalt & Water
L* Values 86.97 86.29 91.61 86.71 83.86
a* Values -0.65 -0.68 -0.57 -0.25 +1.12
b* Values -0.95 +1.82 +0.74 -4.73 -2.73

Conclusions

When creating the pastel crayons, some pigments were easier to use than others. The red ochre pigment was the most difficult of the three to make, as it required a larger quantity of the binders than the other pigments. Opposite of the red ochre was the smalt pigment. These crayons appeared to form very easily in much less time. The yellow ochre fell somewhere in between, differing in difficulty with each binder. Though I questioned whether or not the red ochre and yellow ochre would create quality pastels, each binder successfully held the pigments together to form an easy to use and decent quality crayon. However, the smalt pigment had different results. Though the smalt crayons appeared similar to those of the red ochre and yellow ochre, it was difficult to draw with the smalt pigment. As the red ochre and yellow ochre crayons left deep shades of both colors, the smalt pigment left faint blue marks on the paper. The quality of the smalt crayons is very poor as the crayons appeared too hard and dry to leave deep shades of smalt upon the paper.

Due to the failure of the smalt pigment to produce usable pastels, I considered only the red ochre and yellow ochre pigments when evaluating the most effective binder.

The binder which produced the best results proved to be the oats. The quality is very smooth and thick, as pastels need to appear. The oat crayons were also much easier to draw with as the pigments were more easily transferred from the crayons to the paper. The next best crayons were those made with honey as the appearance is smooth and thick but not as pastel-like as the oat crayons. The gelatin mixture worked well for the red pigment but appeared scratchy and thin for the yellow ochre pigment. The Gum Arabic was more difficult to use than the other pigments due to the stiffness and dryness of each crayon. Though the crayons with only water and pigment created deep shades and smooth appearances, the crayons were too brittle to use more than once as each crayon broke into many pieces as I attempted to draw with them.

In evaluating the colorimeter results, I compared each pigment with different binders. I used the water and pigment mixture as the purest form of the color to compare the other binders to. The results varied as that different binders worked best with various pigments. The red ochre pigment and gelatin mixture produced a color which closely matched the color of the red ochre and water mixture. Yellow ochre pigment and oats produced the best shade of yellow as smalt and Gum Arabic proved to affect the smalt color the least. These finding are surprising, as I had imagined one binder would affect all the pigments the same. However, through these findings, I realize that each pigment is different and therefore, the binders would affect each differently.

Therefore, from my findings, I conclude that expensive binders such as Gum Arabic are not of a better quality than those of inexpensive, household products. Using oats as the binder would be the best approach as the crayons were easier to create, of better quality, and proved to change the color of the binder minimally.

Links

About pastels:

http://ctpastelsociety.com/home.html

http://www.melindarambo.com/pastels.html

Other References

"About Pastels." Connecticut Pastel Society. April, May 2005. <http://ctpastelsociety.com/aboutpastels.html>

deMarrais, Paul. "Making Professional Pastels." David Smith, Creative Solutions for Creative People. April, May 2005. <http://www.danielsmith.com/learn/inksmith/200110/>

 

Acknowledgements

I would like the thank Dr. Bordley for his assistance in my project.