During its history, the Cambridge Glass Company made pink transparent glass that was advertised in the colors of Peach-Blo, Dianthus Pink, LaRosa. and late "Pink" according to the Colors In Cambridge Glass book published by NCC in 1984. Peach-Blo was first advertised in August 1925. That book indicates that pink is a very hard color to maintain while working a pot of glass and tends to have a considerable amount of variation in density and sparkle. Furthermore, the colors book states: "In 1934 the color name was changed to Dlanthus Pink with no apparent formula change."
Despite this assertion that Peach-Blo and Dianthus Pink are the same color, I have noticed that some collectors and dealers of Cambridge glass continue to use these names for what they consider to be unique pink colors. There is no question that transparent pink glass produced by Cambridge in the 1920s and 1930s had a wide range of color. I am very aware of this because of the range of colors of the transparent pink swans from the 20s and 30s in my collection (3" Type 1 and 3" Type 2, but only Type 1 for the other sizes).
The switch from the Type 1 mold to the new Type 2 mold for the 3" swan occurred sometime during 1933. Therefore, if Dlanthus Pink was actually a new color introduced in 1934, that would mean all 3" Type 1 swans are Peach-Blo and almost all 3" Type 2 Swans are Dianthus Pink. It turns out the 3" swans have the same range of color for both Type 1 and Type 2. Both types can be found in a broad range of pink from a peachy color with a warm glow, to a deep reddish pink, to a very delicate and light pink. Also, I have an 8½" Type 1 swan in my collection that is a dark brownish red, but it too is a transparent pink and therefore must be considered Peach-Blo/Dianthus Pink.
I have touched bases with most of the key researchers of glass within NCC, and I have found no one who has found evidence to refute the contention in the Colors book that Peach-Blo and Dianthus Pink are simply different names for the same color.
In checking with Lynn Welker on this topic, he suggested I contact Bill Courter, the president (Bright Knight) of the Aladdin Knights collector club to research the formulas used to make Cambridge glass. Bill was the banquet speaker at the 1994 NCC Convention. Bill befriended Mr. Henry Hellmers who was the glass chemist at the Cambridge glass factory from 1930 to 1932. After those years at Cambridge. Mr. Hellmers moved on to work as a glass chemist at Heisey, Akro Agate, Aladdin Industries, and several, other glass manufacturers. At the 1994 NCC Convention Bill Courier spoke on the topic "The Colorful Career of Henry Hellmers."
By the time this article is printed, I will have traveled to Paducah, Kentucky, to visit with Bill and Treva Courter at their home. Bill is a retired horticulture professor from the University of Illinois. Its a small world, because I am a Dairy Science professor at the University of Minnesota and Bill and I mutually know numerous professors of agriculture at the two universities - Illinois and Minnesota.
Henry Hellmers had productive years as the glass chemist at Cambridge. The Cambridge colors he developed include Carmen, Amethyst, Royal Blue, Forest Green, Heatherbloom and Crown Tuscan -- in other words some of the most collectable colors produced by Cambridge. Furthermore, Mr. Hellmers reformulated Ebony and Peach-Blo/Dianthus Pink to make these colors heat resistant.
Hellmers died at the age of 80 in 1978, and shortly after his death, his family passed along his voluminous batch book (2360 formulas for glass labeled by date and glass manufacturer) to Bill Courter. Bill now intends to reproduce the batch book for glass collecting clubs so the impact of Henry Hellmers can be recognized and so collectors will know the actual formulas for colors of glass in their collections.
To provide a sample of future articles on formulas, I will briefly review the eight formulas for "transparent pink" developed by Mr. Hellmers for the Cambridge Glass Company. One formula is dated 1928 and has the notation "Rose Pink." [Apparently Mr. Hellmers did contract work for Cambridge in 1928, before he worked more exclusively for Cambridge beginning in 1930.]
Five formulas are dated 1930 and each has a notation "Blown Stemware," "Heavy Press Ware," "Light Press Ware, Cups, Plates, Etc.", "Heat Resistant Plates, Cups, Pressware" and "Good Color - Little Hard to Press." One formula is from 1931 with the notation Peach-Blo Press & Blown." One final Cambridge formula is from 1932, with the notation of simply "Peach-Blo."
All eight formulas for transparent pink (at least some of them being Peach-Blo/Dianthus Pink) have somewhat different ingredients. Some of these formulas may have been experimental but it seems pretty clear that formulas differed for Peach-Blo/Dianthus Pink depending on whether items were to be pressed or blown, whether items did or didn't need to be heat resistant, and whether items were thin walled or heavy.
Ingredients common to all eight of the Cambridge formulas for transparent pink from 1928 to 1932 were: sand, soda, potash, borax, bt. lime and selenium. Alternative ingredients were: nitrate, arsenic, feldspar, allumina and lead.
I think we will learn conclusively from the Hellmers batch book that numerous formulas that differed somewhat were used to produce a single Cambridge "color". Price and availability of raw materials may have factored into which ingredients were used in a particular batch of a color. Also, I can't help but think that a raw material such as "sand" might not be absolutely consistent from batch to batch of glass that was made from it.
There is good chance Peach-Blo/Dianthus Pink was produced until LaRosa was introduced, perhaps in March 1938. The Colors book indicates LaRosa was discontinued in October 1943, due to a lack of raw materials because of World War II. Apparently no transparent pink was made by Cambridge from 1943 to the initial closing of the factory. Late "pink" was introduced sometime during the reopened period (1955-58).
Evidence to date suggests that the comments regarding Peach-Blo/Dianthus Pink in the Colors in Cambridge Glass book continue to be correct. Specifically, the color name was changed [from Peach-Blo to Dianthus Pink] with no apparent formula change. At least, there was no change of the alternative formulas likely used for this transparent pink color.