Dyed Fur Samples: Part 2

Fur-Mounting System

We next needed a method of mounting the deer and fox furs so that they could be dyed and exposed in the test chamber. [See Part 1 of this series for an explanation on why we chose deer and fox furs.] Acquiring a series of meaningful color measurements from dyed fur demands a sample design that is more sophisticated than dye on quartz plate. The successful mounting system would secure a group of hairs at both ends, creating a flat sheet onto which the dye can be airbrushed. It must completely immobilize the hairs against handling, measurement, and the high rate of airflow inside the test chamber. Any loss or displacement of a dyed hair from the sample surface could be reflected as lost color in our measurements, indistinguishable from the dye fading that we are principally interested in.

In addition, the mounting system must:

  • Be compatible with deer and fox hairs of average length
  • Consistently distribute hairs across the sample to create a relatively planar surface
  • Avoid hair breakage during sample construction, accelerated aging, or measurement
  • Be made from materials that would not slump, melt, migrate, off-gas, or otherwise degrade during accelerated aging
  • Produce samples of consistent size and shape that can be used with a jig to ensure measurements are repeatable
  • Produce samples that can be handled without accidental disruption of hairs
  • Produce samples that can be secured inside the test chamber
  • Be simple and relatively quick to execute
Title/Description of Object:

Early attempts at mounting hair for research samples that were unsuccessful.  AMNH/J. Sybalsky

Our initial experiments cast a wide net. We looked at various types of clips, from binder and bulldog clips to staples and barrettes. These attachments were quick and simple to use, lacked components that would be likely to degrade, and could be adjusted to accommodate any fiber length. But we found that they produced samples that were bulky, insufficiently secure, incompatible with the measurement aperture of our spectrophotometer, or could not easily be standardized for use with a simple jig.

We explored other non-adhesive methods, employing flat materials that can be crimped or heat-sealed to trap hairs at both ends. We laid hairs on top of strips cut from nonwoven polyester and Mylar, folded the ends of each strip over the hairs, and sealed them in place. While these mounts created visually attractive, planar samples that could be made to fit into preexisting sample holders in our test chamber, the heat seal did not pinch the hairs well enough to fully immobilize them. A similar design using strips of aluminum sheet with crimped ends was more secure, with improved tightness and rigidity. They were, however, laborious to execute and would be challenging to standardize. A further adaptation using pieces of aluminum vapor-barrier tape in place of crimping made sample construction much easier, but introduced an organic adhesive. (See images above.)

Next, we looked into designs based on the concept of an embroidery hoop: we laid hairs across the open end of a cylindrical piece of steel hardware, then secured them in place using fasteners that could be wrapped and tightened around the cylinder. Stainless steel zip ties and hose clamps both held well in general, but fibers were loose around the locking mechanism in both cases. Execution was fussy, leaving fibers inconsistently distributed. (See images above.)

Fruitful discussions with several colleagues pointed us toward polyethylene sample holders designed for X-ray fluorescence (XRF) analysis of powdered samples. These holders usually consist of several separate components: a cylindrical tube or “cell,” a collar that snaps over the top of the cell, and a cap that covers the bottom end.

To mount the fur onto an XRF sample cup, a small piece is cut from the hide. The hair on the hide is brushed using an eyebrow comb to align the hairs parallel to one another. One end of the cylindrical cell is lined with Teflon sheet to act as a stable, white backing material during color measurements in case any gaps are left between hairs. The aligned hairs are carefully placed on top of the cell and immobilized by attaching the snap-on collar in a fashion similar to an embroidery hoop. Longer hairs extending from the side of the sample cup are trimmed using a scalpel. Any hairs standing proud of the sample surface and those not trapped by the sample ring are also trimmed away using scissors and tweezers.

1_1

XRF sample cup with Teflon sheet applied to the opening of the cell; the snap-on collar before applying.  AMNH/F. Ritchie

3_1

Applying combed fox hair to the Teflon-covered end of the XRF sample cup. The snap-on collar is added after positioning the hair.  AMNH/F. Ritchie

4_1

Completed fur cup samples  AMNH/F. Ritchie

We found this method of sample construction to be labor-intensive, but it allowed us to make standardized samples more successfully than any other. Nevertheless, before committing ourselves to one method over the others, a trial run in the test chamber was in order. We subjected our two favorite mounting systems, the XRF sample cups and the aluminum sheet and barrier tape, to 600 hours of accelerated aging at 0.35 W/m2, 55% RH, 63ºC black panel temperature, and 48ºC chamber air temperature. Both systems held up to the environment and blowers well. There was no evidence of creep or adhesive migration in the aluminum mounts. In both systems, a few underfur fibers were stirred up above the sample surface by airflow inside the chamber, demonstrating the importance of early removal of fibers inclined to dislodge. This can be accomplished through application of gentle friction or canned air to the sample followed by cutting or tweezing away any loose hairs.

Because of the importance of producing samples of consistent size and shape, we ultimately adopted the mounting method based on the XRF sample cup. A selection of XRF sample cups with different dimensions and features was subsequently tested with our furs. Some were more compatible with the length of our fibers than others, and smaller cups gave us greater control over the distribution of fibers. Among the examples we tested, we felt that the Chemplex SpectroCertified Quality XRF Sample Cup No 3115 worked best.

In total, 300 sample cups were constructed (150 with fox, 150 with deer) and will be used for testing. Future blog posts will describe the testing methods and results.

Caitlin making fur cup

Project intern Caitlin Richeson preparing fur cup samples using fox hair.  AMNH/F. Ritchie

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Dyed Fur Samples: Part 1

The first phase of our lightfastness testing aimed to establish the lightfastness of the Orasol® and similar Sorasolve metal-complex solvent dyes in isolation‒ that is, in the absence of a binder, and without a chemically active substrate that could potentially influence the behavior of the dyes or interfere with the measurement of color change. (See earlier posts to explain the project plan and selected dyes. Future posts will explain the results of this testing, which is currently underway.)

The second phase of testing uses accelerated aging and periodic color measurements to look at how lightfastness is affected when Orasol dyes are applied to aged, faded furs as they are used in a recoloring treatment. We expect to see substrate impacts on lightfastness for several reasons:

  • As furs age, they produce reaction products that may affect the chemical behavior of an applied dye.
  • Compared to quartz, dyes deposit very differently onto hair. There is also significant variation among fresh and aged fiber surfaces, and among fibers from different animals.
  • The optical properties of dyed fibers differ from those of dye films on quartz. Differences in how the sample reflects and/or absorbs incident light affects its total light exposure dose and its apparent color.

Fur Selection

Several considerations played an important role in our selection of animal fur substrates. First, we sought furs that are light in color. The principle reason for this was that a light-colored substrate was needed to control our dye application and keep reflectance spectra minima in the range of 30–40 percent (see earlier post for reflectance discussion). For consistency of samples, the furs also needed to be as uniform in color as possible. To facilitate sample mounting, longer fibers were preferred over short. The fibers themselves should present minimal color change upon exposure to accelerated aging, ensuring that the dye (and not the fiber) is the primary contributor to any color change observed in a dyed fiber. Finally, we aimed to represent some of the naturally occurring variation in mammal furs, from hollow guard hairs and bristles to awns and underfur.

arctic fox skin

Arctic fox skin used for research samples.  AMNH/F. Ritchie

We ultimately chose furs from two animals with naturally white coats: an arctic fox and a white-tailed deer. The latter is fully white but not a true albino, a variation selectively bred to be whiter than the closely related “spotted” piebald. The arctic fox represents fine, smooth-haired fur-bearing mammals, while the deer offers hollow guard hairs.

However, there is an important downside to using white furs such as these. As we pointed out in our discussion of backing materials for our samples on quartz, light-colored substrates reflect and scatter proportionately more light than dark ones. Transparent dye films applied to highly light-scattering substrates will be exposed twice: once directly by the lamps, and a second time by reflected light from below, increasing the light-exposure dose. While faded historic taxidermy may be light in color, most examples are generally still darker than these bright white furs.

deer hide

White-tailed deer hide used for research samples.  AMNH/F. Ritchie

Consequently, light-scattering plays a larger role in the fading of our samples than is expected in the treatment that we are modeling. While it could be argued that our samples represent a worst-case scenario with respect to the impact of specimen color on the longevity of recoloring treatment, we acknowledge that the use of white furs is a compromise needed to consistently produce the most light-sensitive dye application possible.

Tanning

The impact of different tanning methods on the dyes under investigation is unknown and offers an interesting avenue for further research, but this is not addressed as part of our current project. Nevertheless, in order that they more closely model taxidermy in the American Museum of Natural History collection, the fox and deer pelts for this project were tanned according to methods representative of those historically used at the Museum.

leathers

Scraps of leathers prepared using different techniques and finishes. The type of tan can affect the condition of a taxidermy mount overtime.  AMNH/F. Ritchie

When considering the production and acquisition of historical taxidermy at the Museum, particularly for use in dioramas, the period of interest spans from approximately 1925 to 1965. Though we do not have a complete understanding of all the tanning methods in use at, and for, the Museum during this 40-year time frame, we were able to partner with a local tanner trained by Sinclair Clark, a renowned tanner who was on staff at the Museum around 1924–1927. Clark later set up tanneries in other locations, but maintained his relationship with the Museum tannery over a long period of time.

In general terms, Clark’s method involves the following:

  • The skin is salted to remove moisture and stabilize it prior to tanning
  • Tanning begins with rehydration in a saltwater bath until the skin is soft and pliable
  • It is next soaked in an acid pickle until swollen, and then shaved down on a fleshing machine or by hand
  • The skin is returned to the pickle, and, if needed, shaved again
  • The skin is then removed from the pickle and the acid is neutralized
  • Warmed oil is applied either by hand or with a “kicking” machine
  • The skin is left to sit overnight or for one day before being tumbled in hardwood sawdust until dry and soft
deer hide cross section

Cross section of the white-tailed deer hide used for the research samples.  AMNH/F. Ritchie

The upcoming Part 2 post will describe how we are mounting the furs to run as research samples.

It’s All In the Preparation: Part 2

With our sample set chosen, our substrate selected, and our sample mounts determined, we next needed to devise a process for applying the dyes. Since the ultimate treatment would likely involve airbrushing, we chose to spray deposit the dyes onto the quartz plates. For this we had to consider and anticipate the different requirements and challenges that might arise in the application, including:

  1. What is the best technique for mixing the dye solutions?
  2. What delivery system gives us even coverage and the most control?
  3. How much dye should be applied and how can we measure that?
  4. What shape should the dye film deposit be to allow repeatable color measurements?
  5. How should we mask the substrate to achieve the desired sample shape?
  6. How do we economize and reuse the substrates?

1.  Mixing: Our mixing procedure reflects the method reported by Ciba-Geigy (the manufacturer of Orasol® dyes before its acquisition by BASF in 2008) in the literature describing their product testing. [Ciba_orasol_brochure] Where Ciba’s protocol is unclear, we have standardized our method based on our experience of what works well.

The powdered dye is measured and then incorporated into a volume of solvent to create a 1% (weight to volume) solution. The solution is stirred using a magnetic stirrer for approximately one hour. After mixing, the solution rests for approximately 24 hours. During this period, undissolved dye particles settle, and afterwards the solution can be decanted into a new glass bottle.

Sample Preparation

Former project intern Ersang Ma decanting newly mixed dye into the spray bottle. AMNH/B. Hunan

We have observed that when left in storage, the dye solutions appear to have a shelf life. In some cases we have seen changes in the color of the solution and the formation of crystalline deposits. We haven’t looked into what these changes might mean for the behavior of the solution. We have just taken them as indications that something has changed, and in response, we prepare fresh dye solutions for each round of sample production.

2.  Delivery System: We elected to apply the dye to the quartz plates using an airbrush. Airbrushing is, in general, the delivery method that permits the greatest range of expressive use of the dyes in taxidermy restoration, where controlling color value, gradation, and blending is critical to achieving a successful result. For the same reasons, it is easier to control the amount of dye deposited onto the plate using an airbrush than by brush, roller, dropper, or dipping techniques. The spray application facilitates putting down a thin, even layer, which can be gradually built up to the desired level.

during spraying

Former project intern Ersang Ma spraying dye onto a masked quartz plate. AMNH/F. Ritchie

Our dye solutions are applied to quartz plates using an Iwata Eclipse HP-BCS airbrush at 20 psi of air pressure from a compressor. Of course, having elected to use the airbrush, our samples are always prepared in a fume hood while the researcher is wearing appropriate personal protective equipment.

3.  Controlling Dye Application: It is important to control the dye application because the color produced by a medium-value application is inherently more light-sensitive than a heavy or light application of the same color. The sensitivity of the medium-value color derives from its reflectance spectrum having values that are not pinned at the low values (for very dark colors) or high values (for very light). It has also been found that for a given amount of dye loss, reflectance values around 30-40% show the largest increase. So when we spray our dye solutions on the quartz plates, we are attempting to produce samples whose reflectance spectra have minima that fall in that range. Doing so also avoids pinning large parts of the spectrum at the very high or low reflectance levels. (Specifics of reflectance spectra will be described in an upcoming post.)

However, controlling the amount of dye deposited onto the plate, even in approximate terms, presents significant challenges. Theoretically it would be possible to accurately measure the weight of the dye deposited, but adjusting one’s delivery to repeatedly match this measurement is fanciful. A more realistic approach to dealing with this uncertainty is to aim for the most sensitive application in which color change can be accurately measured and described; that is, the lightest application that is not so light as to make impossible the observation and measurement of fading.

Experiments conducted for the paint industry have demonstrated that such samples have a minimum reflectance of 30-40%; that is, in the spectrum of light reflected from the sample surface, the amount of light reflected at the most readily absorbed wavelength is 30-40%. When this condition is met, the entire spectrum will fall between the extremes of light and dark, so that there is room for it to gradually rise or fall as the colorant fades or darkens.

relfectance percentages

Mockup demonstrating how much dye corresponds to different reflectance values. AMNH/F. Ritchie

Since it can be difficult to visually gauge whether a particular dye sample on a clear plate meets these criteria, we created a set of small mockups with white backgrounds that reflect a range of minimum reflectance values (14% – 76%). These give us a sense of what each of those dye loadings look like. To arrive more precisely at the 30-40% minimum reflectance value in our samples, in the course of spraying, each sample is placed on a white membrane filter backing and measured using the spectrophotometer. More dye is added, if needed, until the desired loading is achieved.

color reading during spraying

Current project intern Caitlin Richeson measuring the percent reflectance on a freshly-sprayed quartz plate dye sample using a handheld spectrophotometer. AMNH/F. Ritchie

4.  Sample Shape: As our last post mentioned, our experimental procedure calls for taking periodic color measurements from each replicate throughout the duration of the exposure. At each time index, the values obtained from three locations on the plate are measured and averaged, to produce an overall measurement for the sample. In order to accurately calculate color change (which we will discuss in depth in an upcoming post), it is important that these three locations are reproducible, i.e., they do not change from measurement to measurement.

jig positions

Jig used to hold the quartz plate dye samples during color measurements. The samples are placed in each of the three positions for the three readings obtained using a spectrophotometer. AMNH/F. Ritchie

This requirement informed the design of a small jig with a wide T-shaped window into which the quartz plate can be inserted in any of three positions: left, right, and bottom. The spectrophotometer is placed in a fixed position atop the window. As each set of measurements is taken, the plate is moved through the three arms of the T. As long as the plate is inserted into the jig in the same orientation each time, the three measurement locations are constant. To ensure proper orientation of the quartz plates for each round of measurement, the dyes are applied to form an inverted T-shaped deposit on the plate. This irregular shape ensures the plate is properly orientated to provide the three viable measurement locations. If the plate were positioned in the jig in an incorrect orientation, at least one measurement would include an undyed area on the plate, giving the researcher an immediate cue that she has made a positioning error.

5.  Masking: A metal mask easily clips on to the plate to expose the same T-shape sample area in each application. After application, the metal mask is removed and cleaned before applying the next dye solution.

assembling samples

Assembling the bare quartz plate, metal mask, and backing material (to help see how much dye has deposited onto the clear plate) before spraying with dye. AMNH/F. Ritchie

6.  Reusing substrates: Since our quartz plates are in limited supply, their use does not end after a test cycle. After final color measurements and final photography, the plates are cleaned so that they can be reused for the next test round. Our cleaning procedure is intended to ensure that the plates are free of contaminants prior to the application of dye. Although our substrate is chemically inert, contaminants or dye degradation products can interfere with the results. Through testing and troubleshooting, a streamlined process is now in place:

Quartz Plate Cleaning Procedure:

  1. The quartz plates are first wiped with a solvent to remove grease and/or remaining dyes left on the surface from the last completed test cycle. The solvent we have chosen to use for this process is acetone, as it is effective on grease and all of the dyes.
  2. Solvent cleaning alone is not sufficient to fully remove the dye and all residues from the plates. The initial solvent cleaning step can redeposit dye in the roughened edges of the plate, where it becomes stubbornly embedded. Furthermore, we found that many dyes as they age create a thin, transparent, insoluble film on the plate – a “ghost” pattern on the surface, which accepts new dye solution differently than the virgin quartz surface. To remove these residual deposits and “ghosts,” we next polish the plates with Bueller MetaDi Monocrystalline Diamond Polish, 1 μm. The monocrystalline diamond particles are single grain particles with sharp edges. These particles are suspended in a fluid, which we can spray onto the plates and gently buff the surface of the quartz using cotton pads. The polish removes the residual dye and insoluble deposits on the plates.
  3. Next, the quartz plates are transferred to a bath of detergent and water. The detergent, Sparkleen, (Sodium Carbonate 10 to 25%, Sodium Dodecylbenzenesulfonate 1 to 10%, non-ionic detergent 1 to 10%) is a conventional laboratory glassware detergent that aids in the removal of both organic and inorganic deposits.
  4. Finally, after the quartz plates have been rinsed of the detergent, they are allowed to dry and then receive a final wipe with acetone. This final round of solvent cleaning is intended to ensure that no contaminants are left on the plates from handling. Once the plates are clean, they are ready to be sprayed with dye once again.

The preparation of the quartz plates is both time-consuming and stringent, but is an essential part of the experimental procedure.

A subset of 9 of the Orasol dye colors, dissolved in propylene glycol monomethyl ether (PGME) and airbrushed to the quartz plate substrate. AMNH/F. Ritchie

 

What’s the Plan?

The research team had a good sense of the relative lightfastness of the Orasol dyes as a result of the renovation research, but how long could we expect the dyes to last inside an actual diorama environment? How could we better understand the ease of removal of the dyes from the animal hairs – is there a way to manipulate the dyes’ ability to penetrate or “fix” to the substrate? Could the dyes potentially cause the hairs to degrade faster inside the harsh diorama environment, or do they block the light and slow down damage – or both?

These questions acted as the foundation to the current collaboration and the focal point of the project research. Since beginning the project last fall, the majority of the work to date has focused on questions concerning lightfastness. The research team has decided to narrow future investigation to the Orasol line of dyes, rather than bringing new materials into the research plan. While the research team also looked into water soluble dyes, fiber reactive dyes, other metal-complex dyes, and some acid dyes, we were the most interested in applications that minimized the use of water.  Many of these alternative colorants are water-soluble and not appropriate for use on water-sensitive materials, require rinsing to remove excess dye and dye-bath residues, or their appearance during application does not represent their final color. The Orasol dyes remained the most promising among the materials available, as they lack the major drawbacks of some of the alternative colorants. The experimental work began in late summer 2014, starting with a large amount of sample preparation.

Lightfastness and Measuring Color Change

The first phase of the research plan tackles the question of how resistant the dyes are to fading – determining the lightfastness according to established standards (ASTM D4303) when applied without a binder or substrate that might interact with the dye. The testing done during the renovation project used wool flannel, an unstable substrate that also can discolor when aged, which could complicate being able to detect color change of the dye. For our current round of tests, we are replacing the wool flannel substrates with quartz plates, an inert substrate not expected to interact with the dye. The plates will be prepared according to methods used for testing in the paint industry – we’ll get into more detail about sample prep in future posts. Lightfastness test results will allow colors to be ranked and ASTM lightfastness ratings to be assigned to each dye color.

Intern Ersang Ma preparing dye for application to quartz plates

Intern Ersang Ma preparing dye for application to quartz plates.

Additionally, we will be developing an aging protocol that mimics ASTMD 4303, but more closely reflects the UV-filtered light conditions, temperature, and RH that are recorded inside of the AMNH habitat dioramas. This will give us a ranking of the dyes when exposed to an environment that is more similar to what the taxidermy is experiencing inside the diorama.

150  quartz plates with dyes dissolved in various solvents and airbrushed onto quartz plates for the first round of lightfastness testing.

150 quartz plates with dyes dissolved in various solvents and airbrushed onto quartz plates for the first round of lightfastness testing.

On going color measurements throughout both tests will let us better characterize the rate of color change – then we can give projections about how the dyes will hold up over time in our diorama lighting environment. Our initial light dosage calculations indicate a rough equivalence between 1 day of exposure in the environmental aging chamber at these test standards, and 1 year inside the most brightly lit dioramas.

We will also be looking into what impact, if any, solvent choice has on lightfastness and the rate of color change. Early testing during the renovation project suggested that not only can the color appearance of these dyes differ when they are applied in different solvents (as illustrated in the images below), but that the solvent choice may also affect lightfastness.

A 1% solution of the Orasol Red BL dye in MEK (methyl ethyl ketone). The dye is unevenly distributed and with distinct droplets. On the macro level, the swatch is a dark mauve.

A 1% solution of the Orasol Red BL dye in MEK (methyl ethyl ketone) applied to wool textile. The dye is unevenly distributed and with distinct droplets. On the macro level, the swatch is a dark mauve.

A 1% solution of the Orasol Red BL dye in methanol. The same dye delivered in methanol results in a more level film and a brighter color; the darkening you see is a product of higher hairs catching the airbrush more and getting more deposition.

A 1% solution of the Orasol Red BL dye in methanol. The same dye delivered in methanol results in a more level film and a brighter color; the darkening you see is a product of higher hairs catching the airbrush more and getting more deposition.

A 1% solution of the Orasol Red BL dye in PGME (Propylene glycol monomethyl ether). The dye seems to be pulled through the interstices of the weave.  In fact, if you flip the fabric over, the color looks the same on the front and the back.

A 1% solution of the Orasol Red BL dye in PGME (Propylene glycol monomethyl ether). The dye seems to be pulled through the interstices of the weave. In fact, if you flip the fabric over, the color looks the same on the front and the back.

Variations in how the dye is deposited on the substrate might influence the lightfastness of the dye – our initial accelerated aging testing will include dyes in five common solvents.

In addition to tests of the dye on quartz plates, we also need to test the dyes on fur in order to better understand the rate at which we might expect recolored taxidermy to fade or discolor. Accelerated aging tests will be conducted on samples of mounted fur, and the final selection of colors, solvents, and testing conditions will be based on the results from testing the quartz plate samples. From a long list of fur initially considered for testing, examples were narrowed down to only bison, fox, and deer hairs to represent wiry, slick, and hollow-haired fur-bearing mammals. We then had to develop a mounting system that could secure the fur samples against disturbance from handling and air turbulence. It was a challenge to trap both ends of every fiber so that they can be dyed in place while still being able to reliably take consistent color measurements of the same surfaces over the course of testing – hairs mustn’t dislodge because once they are dyed, a lost hair would expose the undyed hairs below and skew the color change measurements. We’ll reveal our mockups and final mount method in our post about sample preparation!

Equipment Purchases

Paul Whitmore watches Alan J. Boerke, a representative from the Q-Lab Corporation, during a training session at AMNH in February 2014.

Paul Whitmore watches Alan J. Boerke, a representative from the Q-Lab Corporation, during a training session at AMNH in February 2014.

For the lightfastness testing during the renovation project, we were able to partner with the Art Conservation Department at Buffalo State College to utilize their artificial aging chamber and spectrophotometer. In support of our current in-depth investigation, the grant funds allowed the AMNH to purchase several major pieces of equipment, including a Q-Sun Xenon Arc Accelerated Aging Test Chamber Xe-3 and an X-Rite Ci62 handheld spectrophotometer. Installation of the aging chamber posed some of greatest challenges in planning, and required extensive assistance from the museum’s plumbers, electricians, and carpenters from our facilities department. We’ll get into some the details of those challenges in a future post.

Orasol dyes and related colors

Over the last several months of planning, we’ve also discovered that it is difficult to obtain small quantities of the BASF Orasol dyes. Few retailers market them, and those that do carry stock that may be many years old. Other retailers use the Orasol name to sell related dyes manufactured by other companies. The true chemical and behavioral equivalence of these dyes is unknown – two dyes with the same name but different manufacturers may have differences in color, solubility, or lightfastness, among other traits. BASF has added and discontinued colors in their Orasol line over time – currently the line includes 26 colors. The previous testing as part of the renovation project included about half of the colors available – we are working to procure samples of all 26 colors. The upcoming lightfastness testing will include both new and old BASF Orasol dyes, as well as related non-BASF dyes – a total of 46 colors in 5 solvents.

And that’s just the lightfastness testing using the aging chamber! We’re expecting these initial cycles of testing to begin next month and continue through the fall and winter, and we’ll be making adjustments to the total number and types of samples to be tested along the way. There are some other avenues of testing we will be conducting, including investigating the rate of color change under real diorama lamps (as opposed to the xenon lamps used in the testing chamber), as well as exploring the possibility of being able to manipulate dye penetration and investigating the long-term effect of dyes on the hair itself.