Qor® Lightfastness Testing Update Beauty and the Best

Qor® Lightfastness Testing Update Beauty and the Best

JUST PAINTPublished by Golden Artist Colors, Inc. / Issue 33 CONTROL EXPOSED CONTROL EXPOSED From Mark Golden We’ve just passed several milestones Tint Tint here at GOLDEN. In June we celebrated our 35th year in business and Barbara and I, our 40th wedding anniversary. Both events began on my folks’ farm and the home of Masstone Masstone Golden Artist Colors. This year also marks some wonderful beginnings. Montserrat Orange Persian Rose ® QoR Watercolor has had an exciting CONTROL EXPOSED CONTROL EXPOSED inaugural year and we’re delighted to share lightfast testing results of these materials. Sarah Sands has summarized Tint Tint the massive undertaking required to assure artists that these materials will stand up to their expectations of a professional watercolor. While completing evaluations for QoR we Masstone Masstone also revisited some Williamsburg colors. Jaune Brilliant Sap Green Again, Sarah shares insights and necessary Test panels showing outdoor exposure results compared to unexposed controls. Jaune Brilliant showed changes to assure artists these materials little change and its formula will remain the same. Other blends will be changing and made with meet the highest quality standards. ASTM 1 rated pigments. Many of you worked with Amy McKinnon, a talented Materials Beauty and the Best: Wrestling with Specialist. Although Amy left GOLDEN to begin a new venture, she Changes in Williamsburg contributed to two articles: the allure of umber pigments and safe use of oils, By Sarah Sands not the sole answer. Before swapping in with and without solvent. new alternatives you have to ask if the For those who wanted a less technical Changes are difficult. As much as you trade-offs are worth the trade. And so entry into the many products and want decisions to be based on facts with all of that in mind, we want to walk resources of GOLDEN, Patti Brady, our and facts alone, there is still a wrestling you through changes that will be taking Working Artist Program Director has that can happen. Paints, and especially place that we hope will make the line provided a quick review of the endless color, escape being easily tied down to more solid, while leaving in place certain creative opportunities offered by our just quantifiable clean choices. Rather, colors that we deemed irreplaceable new A - Z Acrylics set. one can be caught having to choose with any other combination of more We are delighted to announce the between love and lightfastness, between September opening of Judith Linhares, permanent pigments. beauty and the best. Which do you side Continued on next page ‘Flora and Fauna’ at the SAGG. with and when? We want our paintings Judith, an artist “with an uncommon ® vision”, was a longtime friend of the late to last, but also to dazzle and seduce. QoR Lightfastness Carl Plansky. And after all, the choices are often not I am honored to introduce our newest about whether changes in color will Testing Update Materials Specialist, Dr. Cathy Jennings. occur, but at what rate: a long almost She is an amazing watercolorist and imperceptible shift that slowly takes By Sarah Sands teacher, providing the perfect addition place over centuries, or a brighter blaze In the last issue of Just Paint we to our Materials group. that entrances but fades a bit faster or discussed why some QoR Watercolors We are also celebrating our second a bit more? And the choices are even had a Lightfastness rating of NA, or year working with the Alliance for harder when that seductive color is Not Applicable, while most carried the Young Artists & Writers. We have unique; when it comes down to either been supporting the awards program familiar ASTM Lightfastness ratings this or nothing else like it. for the students, which received over of I and II. Essentially this came about 300,000 submissions of art and writing, So that is where we have found because some of the pigments being used as well as recognizing teachers for their ourselves. Stewards of Williamsburg’s at that point were not currently rated outstanding mentorship. This year legacy and responsible for walking that by the American Society for Testing we offered residencies for 3 teachers line, we know that coming at these and Materials (ASTM) although all of advancing their own painting practice. choices with just spectrophotometer Mark them were in the process of finishing up readings and lightfastness test results is Continued on page 5 Issue 33 page 1 ©2015 Golden Artist Colors, Inc. Lightfastness Ratings Based on ASTM D4303 Colors Currently Remaining ‘NA’ ASTM Assigned Units of change GOLDEN Assigned Color Pigment(s) LF Rating Notes (Delta E) after exposure Pigment being tested 2 Cobalt Green PG 26 NA to 1260 MJ/m total solar for first time. Results radiation. expected early 2016. (3 months South Florida / SF Cobalt Violet Light PV 49 NA PV 49 performed well 410 hours Xenon) in linseed oil. Testing of safflower version I 0-4 Excellent to be completed in II 4-8 Good early 2016. French Ardoise Grey PBk 19 NA Other versions of III 8-16 Fair PBk 19 and NBr 8 French Cassel Earth NBr 8, PBr 7 NA Table 1 being used have performed well. Testing of these Origin of the NA’s that are still in particular sources to the process of be completed in early Embedded for seemingly forever within completing even 2016. the Williamsburg line has been a list of these initial tests, All Interference and Mica-Based with NA Nature of pigments some 23 colors that have a lightfastness does not allow for as well as all the Iridescent Colors Titanium White rating of “NA”, or Not Applicable, and/or Iron Oxide lightfastness ratings Iridescent and based on ASTM because one or more pigments in their Coatings Interference D4303. formulation has never gone through colors, (Table 2) Table 2 official lightfastness testing based on where the nature of ASTM D4303, which still remains the the pigment does not allow us to take very stable and we would certainly retest only recognized standard for assessing spectrophotometer readings, nor to should that change. In fact, the French lightfastness for art materials. And that cast them as tints with Titanium White Cassel Earth listed in Table 2, ‘Colors is something we have wanted to remedy without masking them. Currently Remaining NA’, is an example as obviously NA provides you with very of this. Although also designated as little guidance in terms of permanency. Colors Assigned a GOLDEN NBr 8, and so chemically similar, we felt So, almost two years ago, we started Lightfastness Rating it was critical to test it separately because preparing samples to be put through all it originates from a different supplier, the required procedures. As initial results Representing by far the largest group, each of these colors uses one of nine even though ASTM allows you to submit have filtered in, however, it became clear a pigment from one source and have that that we needed to begin making some pigments that are currently unrated by ASTM: Naphthol AS (PR 187), rating used for the pigment in general; an immediate choices and changes while inherent weakness in the current ASTM we still waited for the last rounds of Cobalt Ammonium Phosphate (PV 49), Diketopyrrole-Pyrrole (PO 73), system that we eventually hope testing to start this Fall. Once everything to address. is finished, the final results will be Powdered Slate (PBk 19), Chrome assembled and formally submitted to Antimony Titanate (PBr 24), Diarylide All of which brings us to the last three ASTM sometime early next year. Yellow (PY 83), Quinacridone (PR 206), colors: Alizarin Orange, Alizarin Yellow Bituminous Earth (Natural Brown 8 and Indian Yellow. Unfortunately the A New Lightfastness Rating to [NBr 8]) and PW 5, a complex co- pigment at the center of these, a type Replace Most NA Ratings precipitate of barium sulfate and zinc of Diarylide Yellow, comes in various sulfide. Ten of the colors, from Carl’s While we believe every pigment forms that all share the same Color Index Crimson to Slate Black (Table 3), used in artists’ paints, with a few Name of PY 83. As you can imagine, performed exceptionally well in ASTM exceptions, should carry an official ASTM this can lead to some confusion when D4303 testing, earning a GOLDEN Lightfastness rating based on D4303, the assigning a rating. The opaque version, Lightfastness (LF) rating of Excellent. testing and approval process for newer or which carries the additional designation Please note that a new blend is also unlisted pigments can easily take a couple ‘HR-70’ in its chemical description, being introduced for Quinacridone of years or more. However, during this has excellent lightfastness and is on the Gold Brown using PO 48, an ASTM period we have often completed our own ASTM list of rated pigments. However, rated Quinacridone Gold, in place of the testing ahead of time, following the same our testing showed that the transparent previous PY 83. While both mixtures protocols for exposing prepared tints to 3 version Williamsburg had chosen could earned a GOLDEN LF of Excellent, months outdoors in South Florida, as well only be rated as Fair, or the equivalent to removing PY 83 should further increase as 410 hours of accelerated Xenon, with ASTM III. And here lies the crux of our its durability and allow it to eventually total irradiance in both cases equalling quandary. These three colors have had conform to an official ASTM I rating. the prescribed level of 1260 MJ/m2. exceptionally long and beloved histories Because of this, we felt it was possible Coming after this first block of colors, within the Williamsburg brand, going and important to create an interim our genuine Van Dyke Brown (NBr 8) back to its earliest days.

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