Blues

BLUE FABRICS - Pictures and peak wavelengths (nm) are provided below for selected fabrics used in tsetse and other biting fly traps relative to reference Phthalogen Blue IF3GM from Dystar, Germany. Contrasting examples of several retail fabrics are also provided. Close-ups of fabrics at high magnification are provided elsewhere (Weaves). Although there is no single match to Phthalogen Blue dyed cotton in printed / displayed colours, there are several excellent matches in Pantone® spot colours that span the range of colours on cloth. These spot colours are likely produced with copper phthlaocyanine pigment-based inks. Pantone® 286, 293, 2935 and 2945 match phthalogen blue cottons, with Pantone® 293 the best match to genuine reference fabrics of 4-5% type IF3GM from several sources. Pantone® 300 is another colour of special interest as it is the best match to Procion Tuquoise M-G dyed cotton, which is based on sulphonated copper phthlaocyanine. Pantone® 300 is a nearly "pure cyan" and is sometimes referred to as "azure"; it was adopted in 2003 as the official blue of the Scottish Flag (BBC News). Suppliers sometimes provide Pantone® codes for their products along with descriptive names (e.g. nylon flag and banner cloth at Arista Flag Corporation, San Diego Plastics provides an index to Acrylite acrylic sheet from Cyro). Letraset® Pantone® Tria™ marker pens (in art supply stores) are a convenient retail source for real examples. Detailed technical information on Phthalogen Blue dyestuffs is provided in Blue Dyes. Graphs and reflectance data are provided below in EXCEL for a few fabrics with a complete set of data available in Resources for Researchers. Selected information is provided here for the fabrics tested in Mihok (2002). Appendix 1 from this publication is available here, and images of the fabrics tested are provided in Experiments with Fabrics. Scans are at 150 pixels per inch, with each block at 100 x 75 pixels. Monitors, printers and scanners will not reproduce colours exactly without considerable technical effort. Hence, do not use these images for anything more than qualitative guidance. Reference Pantone® Matching System colours are shown below - Pantone XXX CVC (Color Video Coated)
286	293	2935	2945	300
Phthalogen Cloth	~ Phthalogen Blue IF3GM	Phthalogen Cloth	Phthalogen Cloth	~ Procion Turquoise M-G
I have a basic interest in the phthalogen blue and other metal phthalocyanine dyes that are being used to produce the blue fabrics that researchers use in tsetse and other biting fly traps. I'd be happy to exchange samples to learn more about what is being used around the world. Contact me at smihok@rogers.com.

Fabrics used in Traps for Tsetse Although exact reflectance profiles and peak wavelengths vary, most of these fabrics have CIE dominant wavelengths of about 478 nm. The hue angle is about 270-275°.
	Reference - 465 nm, Phthalogen Brilliant Blue IF3GM 4% dyeing of cotton cloth, continuous pad-bake process Dystar, Germany
	Reference - 465 nm, Phthalogen Brilliant Blue IF3GK 4% dyeing of cotton thread, exhaust process Dystar, Germany
	466 nm, Cotton Drill used in F3 and Epsilon traps in central and southern Africa Bonar Industries, Zimbabwe
	450 nm, Phthalogen Blue Cotton Drill used for large-scale production of NG2G traps in Ethiopia Awassa Textile Factory, Ethiopia
	467 nm, Phthalogen Blue Cotton Drill used for large-scale production of NG2G traps in Kenya Mount Kenya Textiles, Kenya
	464 nm, Phthalogen Blue Cotton Drill used for many experimental studies, note dye lot variation Mount Kenya Textiles, Kenya
	467 nm, Phthalogen Blue "Jinja" cotton, often used for small-scale trap production in East Africa Retail market, Kenya
	463 nm, Poly / Cot used in West Africa (late 1990s) Les Établissements Gonfreville, Ivory Coast Sample provided by Dominique Cuisance
	464 nm, Poly / Cot used at CIRDES (1996) Les Établissements Gonfreville, Ivory Coast Sample provided by Sandrine Amsler-Delafosse
	466 nm, "Santiago" Poly/ Cot used at CIRDES (2003) Les Établissements Gonfreville, Ivory Coast Sample provided by Marc Desquesnes
	450 nm, Poly / Cot used in the F3 trap at ITC (1996) Banjul, The Gambia Sample provided by Momodou Ceesay
	442 nm, Polyester #15 (Taiwan, 1997), opaque version of former "VF Pongee 2" used in further experimental trials following Mihok (2002)
	463 nm, Plastic in the bipyramidal trap used for Glossina fuscipes in the Central African Republic France, sample provided Dominique Cuisance
	Blue Reference Patch Eastman Kodak Colour Separation Guide Q-14

Practical Options

Pacific Blue 10k 466 nm, This is Sunbrella (Pacific Blue, # 6001) a tough and durable canvas made from solution-dyed acrylic; it also comes in black (#6008). It is an excellent match to 100% cotton dyed with Phthalogen Blue IF3GM. One can solution-dye acrylic with copper phthalocyanine, so the colour Pacific Blue is likely produced with this exact pigment. Sunbrella is extremely light-fast (see Fading). It is designed for outdoor use in awnings, patio and deck furniture, boat covers, etc. It is available from many retail sources; one mail order site in the USA is Outdoor Fabrics. I have also tested Sunbrella "seconds"; they are suitable for traps (an excellent price at Fabric Warehouse). Sunbrella without the water-repellent fluorocarbon finish is also often available in selected colours as "untreated fabric" from Rochford Supply (phone if it is not listed, untreated black is routinely available).

I have completed several well-replicated trials of Nzi traps made from Sunbrella Pacific Blue awning fabric in place of Phthalogen Blue cotton. Catches have been good to excellent with equitable catches of most species. Until more fabrics are tested in different environments for different species, Sunbrella is probably the safest current choice for trap construction outside of the tropics.

I have only tested the standard awning fabric. It has a fluorocarbon finish and is matt in appearance on both sides. This special finish is one of the reasons why Sunbrella fabric is extremely light-fast. Fluorocarbon films are also commonly used to protect materials against damage from ultraviolet radiation.

There are many other colour-fast marine fabrics in polyester and/or acrylic that may be suitable for traps; unfortunately, most of these have shiny finishes. For a comprehensive selection see Rochford Supply. The solution-dyed, fluorcarbon-coated polyester canvas Top Notch Blue #563 from MarChem Coated Fabrics is noteworthy as it has a truly matt finish similar to Sunbrella. From limited tests in 2007, it appears to be as good, if not better, than Sunbrella Pacific Blue for tabanids and stable flies. It was introduced in 2005.

Good Polyester / Cotton matches to Phthlaogen Blue
Below are some 65% polyester - 35% cotton European fabrics that *may be suitable* for trap construction. These fabrics are very similar to the Santiago Poly/Cot from the Ivory Coast, which has been used routinely since the 1980's for making tsetse traps in West Africa. Santiago fabric is still for being produced (November 2007).
	453 nm, "Azur" twill #S250 - Phthalogen Blue IF3GM is part of the dye mix used for this colour, 250 grams per square metre. "Azur" is also available in two other twills - S300 & SuperMAINE (November, 2007) TDV Industries, France
	453 nm, New Azzurro Blue in fabric Utopia, plain weave, 170 grams per square metre (1996, this colour may be a special order) Klopman International
	453 nm, New Azzurro Blue in fabric Indestructible, twill weave, 245 grams per square metre (1996, this colour may be a special order) Klopman International
Examples of Poor Fabric Choices
Royal Blue "Sergeant"	434 nm, Col. 3006 , 65% polyester / 35% cotton J. Ennis Fabrics, Canada I tested this fabric several years ago as a potentially-convenient choice "off the shelf" in Canada. It is a complex blue with some ultraviolet reflectance. Fly catches and light-fastness were both poor. This shows how difficult it is to substitute any generic retail fabric for an optimal material (i.e. "Phthalogen Blue" cotton).
Royal Peacock	Nylon Flag/Banner Cloth (Dupont Solar Max^® nylon) I have tested royal blue (448 nm) and peacock blue (458 nm) of this special fabric made for outdoor applications; there are many retail sources (Arista Flag Corporation, Beacon Fabrics). SolarMax at 200 Denier is relatively light-weight, and hence, translucent. It has the smooth, shiny texture typical of nylon. Unfortunately, catches of several biting flies were lower with Nzi traps made from this economical fabric, and from a similar nylon in royal blue (Mihok et al., 2006). The black may nevertheless be useful for traps made with more optimal blue fabrics, as SolarMax is economical and colour-fast. Further tests of SolarMax for other fauna could be attempted, but I do not recommend testing any of the other blues (electric, french, process blue) as they are not very colour-fast. There are many, many nylons on the market, but it is difficult to find products that will remain consistent through time. For example, I have examined several shades of blue "pack cloth" from different source, and have not been satisfied with colour fastness. The blacks, however, may be be OK (6 months exposure so far).
Historical Fabrics Taiwan Vietnam Recent Fabrics Polyester Poly/Viscose	Experimental Polyesters for Tsetse Traps Vestergaard Frandsen A/S In the mid-1990's, VF in Denmark introduced blue / royal blue, texturized polyester fabrics for tsetse traps. The "Taiwan" fabric (439 nm) is a slightly improved version of "VF Pongee 1" mentioned in Mihok (2002) [from 1997]. Some of these early fabrics performed well, and some did not, sometimes unpredictably. Poor performance was common for biting flies and also for savannah species of tsetse. Polyester fabrics clearly do not perform well in all possible contexts, even with a good colour match to phthalogen blue (shininess, polarized light, ultraviolet reflectance?). Since Mihok (2002), the company has changed its products several times. This has been the result of changes in textile mills, and attempts to improve deficiencies in performance. In late 2002, I tested the unusually textured "Vietnam" fabric (426 nm) that was being sold that year [assumed to be a new version of VF #11 in Royal Blue]. I conducted this test for stable flies only, late in the biting fly season. Traps made with this fabric caught hardly any stable flies; the fabric is no longer sold to the best of my knowledge. In October 2003, VF introduced new, evenly-textured fabrics in "pure, bright blue" (New Blue TC-286). These were made in Vietnam or India in "Polyester" or "Poly/Viscose". They were publicized at ISCTRC in Pretoria. Unfortunately, despite a good colour match to phthalogen blue (459-460 nm peaks), this new line performed poorly for both tabanids and stable flies in a test I conducted in Russell, Ontario. I have abandoned any further work with VF fabrics. The company is no longer selling this bulk fabric, although it still makes traps for researchers on request (personal communication, November 2007). Tests of these recent VF fabrics are documented in the following publication: Mihok, S., Carlson, D.A., Krafsur, E.S. & Foil, L.D. (2006) Performance of the Nzi and other traps for biting flies in North America. Bulletin of Entomological Research 96, 387-397. PubMed

SPECTRA - Graphs of reflectance from 370 to 790 nm are provided below for selected fabrics. The readings were taken from a single layer of new fabric using a Li-Cor 1800 spectroradiometer with an integrating sphere. Readings in the ultraviolet below 400 nm are only semi-quantitative.

Spectral Reflectance Data and Graphs (EXCEL, 574k)

A large compendium of published and unpublished fabric spectra, and other technical information of interest to researchers, is provided on the page Fabric Resources.

Spectra for two "standard" fabrics used in East Africa (Phthalogen Blue cotton) and West Africa (Santiago Poly/Cot) are published in:

PHTHALOGEN

Green, C.H. (1988) The effect of colour on trap- and screen-oriented responses in Glossina palpalis palpalis (Robineau-Desvoidy) (Diptera Glossinidae). Bulletin of Entomological Research 78, 591-604.

SANTIAGO

Laveissière, C., Couret, D. & Grébaut, P. (1987) Recherche sur les écrans pour la lutte contre les glossines en region forestière de Côte d'Ivoire. Mise au point d'un nouvel écran. Cahiers ORSTOM, séries Entomologie médicale et Parasitologie 25, 145-164.

Blue Cotton Spectra 8k

Note the simple peak of all samples in the blue region with some differences in the degree of saturation due to the efficiency of dyeing and the weight of the fabrics. The high reflectance of the nominal "phthalogen" sample from Ethiopia in the infrared, and other properties of this fabric, indicate the use of dyes other than genuine phthalogen blue IF3GM to reproduce this special blue.

Blue Synthetic Spectra 8k

Synthetics and polyester / cotton blends often have more complex reflectance patterns than cotton due to the use of multiple dyes to colour the different fibres. Peaks are sometimes broad, or even doubled (VF Polyester #15). Ultraviolet reflectance is usually higher than with cotton but can easily be manipulated with ultraviolet absorbing additives. Note the high 25% reflectance at 400 nm in the Gambia P/C. A shoulder in the infra-red (>700 nm), sometimes extending into the far red (VF Polyester #15), is common.

Blue Poly Cotton Spectra 8k

Here are three examples of 65% polyester / 35% cotton blends from one source (Klopman International) in two colours (New Azzurro and Blade Blue) compared with 100% cotton drill from Zimbabwe dyed with Phthalogen Blue. The New Azurro is a good match to phthalogen blue.

NATURAL MATERIALS - An unexploited resource?
	Traditional plant fibres used to weave baskets and mats may have potential as components of traps. Natural fibres could either be used for structural purposes to support fabric elements, or could be dyed or painted to provide appropriate colour stimuli. Modest fly catches are possible even in traps with no blue components. Animal skins may also be a potentially useful material for the construction of innovative traps.
Phoenix reclinata	The palm tree used to weave the Selen mat found in nearly every household in Ethiopia
A BAD CHOICE - but an interesting material?
This extremely bright material is Tyvek®, a light-weight, tough synthetic made from high-density polyethylene fibres. It feels like paper, but is easily sewn. It has very high ultraviolet reflectance, and an even reflectance across the visible range. Tyvek® can be printed, coated or laminated to produce many colours. To my knowledge, it has never been used in tsetse or biting fly traps, but could be useful for traps that target nonbiting flies (Muscidae). These are typically all-white rather than blue-black. Pickens, L.G. & Hayes, D.K. (1984) Evaluation of a new face fly, Musca autumnalis, and stable fly, Stomoxys calcitrans, Muscidae, trap which segregates the catch of the 2 species. Environmental Entomology 13, 1256-1260.
I experimented with an all-Tyvek® Nzi trap in July 2003. The trap had a white polyester netting cone; otherwise all panels were from Tyvek®. This trap caught very few flies or insects of any kind, biting or nonbiting. Nearby, blue and black Nzi traps made from various fabrics caught large numbers of biting flies. I added panels of blue or black cloth to the top shelf and the interior panels of this trap, but this did not improve the catch.
In a more formal experiment, I replaced the back netting portion of a standard Nzi trap with this bright white material. Surprisingly, this minor change in the back of the trap resulted in very low catches. My conclusion is that many biting flies are exquisitely sensitive to the high ultraviolet reflectance of Tyvek®.
Standard Nzi Trap (performs well)	Same Trap with Tyvek® back (performs terribly)