Archive for the ‘Natural Dyes’ Category

Iron (Ferrous Sulfate) Mordant

July 23, 2016

I have always had mixed feelings about using iron as a mordant when dyeing.  Partly because it must be handled in such a way that the yarn/fabric doesn’t contaminate other yarn/fabric with loose iron before it is thoroughly rinsed and also because there is literature that indicates that yarn/fabric is damaged by iron.   On the other side of the equation, is the idea from Charlotte Kwon that even small amounts of iron will help with lightfastness.  I used 2% wog iron in the  logwood experiments so as to mitigate the lightfastness issues with logwood but felt that I needed to have a better understanding of iron used as a mordant.  Damage in historical textiles with gallic/iron pigment and/or tannin/iron dyes has been documented.  Go to your local museum, look at historical textiles dyed with natural dyes, and see how well the blacks are holding up in the textile.

I did some research and came across the following information specific to historical textiles.   Tannin based dyes + iron will damage textiles due to oxidation and/or the formation of sulphuric acid. The sulphuric acid is formed with unattached iron.  If the textiles are thoroughly rinsed, this is less of an issue as the unattached iron is washed away.  It is also possible that some of the damage is due to high temperatures used in dyeing.  Analysis cannot differentiate between heat versus dye damage.

The Colourful Past: origins, chemistry and identification of natural dyestuffs  discusses degradation of silk due primarily to the lack of regulation of silk dyeing. More iron was used in dyeing silk to get dark colors and the silk may not have been well rinsed.  Wool dyeing was regulated; particularly with regard to the amount of iron that could be used and the dye process quality.

Other sources conclude that tannin/iron damage is more of an issue with cotton, linen, and silk because the dye penetrates the whole fiber.  The dye and iron are found through out the matrix.  With wool, the dyes don’t penetrate the interior of the fiber.  If one rinses thoroughly to get rid of any loose iron, then it is possible it will not be an issue.

I came across another article in Dyes in History and Archaeology – Volume 16/17.  The bottom line in this case is that iron and tannins cause the degradation.  Iron used with dyes that do not contain tannins (madder for example) should be stable. The same paper suggests that the post treatment of an historic textile by an extract from the hinau tree which is a gallotannin will cause the binding of the loose ferric ions to the tannin and stop the degradation.

Cardon says something similar – she suggests that the small amount of iron used with reds could also be a factor in the lack of degradation whereas more is used to get black.

Conclusions?  There hasn’t been a lot of research and tannin/iron dye degradation.   The research does suggest that if the yarn/fabric is thoroughly rinsed and the iron % is not high, it is not an issue.  It also suggests that iron can be used safely with non tannin based dyes.  I did not find any studies on lightfastness with iron mordants; I imagine that is the next area of exploration.  This is all book theory.  If one is not creating art work for posterity, it is non-issue.  If one is, more tests are in order.



Cochineal scarlet experiments

June 2, 2015

I did a few experiments to see if I could get scarlet with cochineal and a yellow as straight cochineal even with an acid modifier does not get you there.

The silk and wool were mordanted separately with 25% potassium alum sulfate.  The recipes were cochineal and Osage orange 10%, cochineal 10% Osage orange 5%, cochineal 10%, Osage orange 2%, a separate experiment with calcium nitrate, cochineal 10% quebracho yellow 10%, cochineal 10% Himalayan Rhubarb 5%.  The cochineal was powder from bugs.

The most successful was cochineal 10%, Osage orange 5% on silk.  I also liked the cochineal Himalayan rhubarb on wool.

Below are the Osage orange variations.  The top one is the the one with the most Osage orange; bottom one with the least.


And, the calcium nitrate experiment, quebracho yellow, Himalayan rhubarb, top to bottom. 

I finally put all of these on cards.  The recipe that was the most successful Cardinal red was the Osage Orange at 2%




Down the rabbit hole.

May 12, 2015

Sometimes, a book or an article sends me down a natural dye rabbit hole that consumes a lot of time with not much to show for the effort.  But the exploration is interesting.  In this case, I was reading a book called Natural Colorants  for Dyeing and Lake Pigments Practical Recipes and Their Historic Sources.  In it, there are experiments based on historic recipes which include the use of Potash (K2CO3) either in the dye bath or post dyeing.  I had come across this idea before in Boehmer’s book Koekboya, but never really understood the purpose.  The Navajos and Hopis smoke their dyed wool over wood ash which would seem to accomplish the same end (whatever that end is).  I think I finally found an explanation in Application of Dyestuffs by J. Merritt Matthews.  On page 41, there is a discussion of using a concentrated solution of caustic soda on wool at a cold temperature.  It gives the wool more luster and makes it less susceptible to felting so was used on rugs.  The wool cannot be left in the solution for a long time and it will damage the wool so maybe not a good practice for dyeing. This research led me back to the structure of wool and the question of why different breeds of sheep take dye differently.  Dyers can tell you that a long wool sheep such as churro will take dyes easier than a breed like merino or cormo.  I have never understood why.  I came across a statement in The Science and Teaching with Natural Dyes that dye binds only to the amorphous regions of the fiber and not the tightly packed crystalline regions.  So, perhaps this is the reason the different breeds take dye differently.  I have not come across anything that shows the % by breed of the regions.  There is also a question in the natural dye world, if varying the mordant process will increase the amount of dye take up (increasing the amount of alum).  So, another rabbit hole to explore at some point.   I did come across another statement in Textile Science an explanation of fibre properties that confirmed something that had been in the back of my mind; that for a given weight of wool fibre, courser wools will have fewer fibers than finer wools so one would need to use more dye for the finer wool to get the same color.  That would imply that more mordant would also be required.  Some experiments are probably in order. So, no pictures in this post.  Just a documentation of some of my findings for posterity.

Experiments with cotton shibori scarves

April 6, 2015

Clothroads has cotton shibori dye blanks produced at a mill by Catharine Ellis. I mordanted several of these last year with the recipes that are published in Turkey Red Journal.

I wanted to try the ferrous acetate recipes of Garcia. So, I mixed up some ferrous sulfate and vinegar solutions of various strengths and painted some of the scarves. I didn’t use a thicknener. Two of the scarves were dyed in cochineal. Two of the scarves in a mix of madder and cochineal. They are drying. Then the shibori threads will be pulled and the scarves overdyed.





Natural dye samplers

October 17, 2014

These  pieces have been off the loom for a while but I  haven’t had time to weave in the ends, press, and hem them.  Finally had a chance to get that done,  the wedge weave piece is interesting as each row has a selection of yarns from the same dye pot: silk, wool, superwashh wool, all of which take the dye differently.  The black is not naturally dyed, the other yarns are all dyed with natural dye extracts.

Wedge weave sample

Wedge weave sample

Natural dye sampler

Natural dye sampler



Organic indigo vats

August 15, 2013

In anticipation of the class I am teaching at Taos Wool Festival this year, I decided to get start some organic indigo vats.  I used Garcia’s 1-2-3 recipe more or less.  Some of the materials were hard to measure like that.

The first vat was an aloe vat.  I ground up some aloe leaves, added indigo and lime.  The ph was around 12.3 on my ph meter.  This was the one that was hard to measure.  The results are below.  It looks weak to me so I will add some more aloe to see if that helps the pot.


001 002  003008

The second vat I used green tea.  As it is an antioxidant, I thought it might work.  Not really.  The ph is high enough but the indigo was clumped at the bottom.

006 005 004

I have added some fructose to this vat to see if that will revive it.


Alum acetate vs Potassium Alum sulfate + soda ash

August 10, 2013

This is an experiment with a yarn that is pearl tencel. As it is considered more of a cellulose yarn, I used two different cellulose mordants. The first was alum acetate. The recipe is from maiwa’s www site, The second recipe was 12% potassium alum sulfate and 15% soda ash. The latter recipe is derived from Liles. Both skeins were soaked in tannin. The soda ash skeins were darker after the mordant step. The soda ash must have interacted with the gall nuts. One set of skeins was dyeing in madder. The other set was dyed in q black. In both cases, the skeins dyes unevenly. The skeins mordanted with alum acetate dyed darker. The hand of the skeins is a little stiff, the washing soda skeins are a little better than the alum acetate as far as hand but they are more uneven in terms of color.

The reason for the two mordant choices is that in the past, I have had problems with the hand on a wool tencel blend with the alum acetate. A friend of mine experimented with other recipes and found the soda ash recipe improves the hand.


The darker skein is the one that was mordanted with soda ash


In this photo, the skein on the left is the alum acetate. The Indigo skein is for comparison.

Taos Wool Festival 2012 – Samples from Botanical Colors Workshop

March 4, 2013

These are samples from a workshop I took at Taos Wool Festival 2012 that was taught by Kathy Hattori.  We used a combination of the botanical colors liquid dyes and a woad and indigo pot.  Some of the samples are wool superwash, some are wool.  The cowl is knit from the non superwash samples.   The first sample in the card is an orphan – a sample of the 50% wool 50% silk from LaLana dyed with chamisa.  As it was from Taos and I purchased this year, I put it in the sample card.

cowl photo sample card twf 2 2012 sample card twf 2012


Piece knit with other samples – a pattern by Lee Meredith – Parallel Lines


yarma_8597993064_m yarma_8598988762_m

Dye day – reds

March 3, 2013

A typical dye run.  The first picture is a 50/50 alpaca dye that was something I didn’t like so it is overdyed in indigo.  The rest are churro skeins, some are grey some are white.

The dyes are myrobalan, osage orange, logwood, indigo, cochineal, brazilwood, and madder.  I have been playing around with different acids with the cochineal (tartaric and oxalic).  The ph needs to get to 3.0 before the reds will appear.

011 009 008004  003 008 001

Black experiment with dye

November 26, 2012

There is one more experiment I wanted to try to get black: using dye extracts with no indigo.  It wasn’t particularly successful on wool.  The best black is equal parts logwood grey (logwood with iron) and Himalayan Rhubarb.  The ones with madder are too red.  That might work better with larger quantities of fiber.   The test fibers are the same as in the previous black post.

From top to bottom
Logwood grey + Him. Rhubarb, equal parts
Logwood + Him. Rhubarb, equal parts
Logwood Grey 2 parts, Him. Rhubarb 1 part, Madder RT 1/2 part
Logwood 2 parts, HR 1 part, Madder RT 1/2 Part
Logwood Grey 2 parts, Osage Orange 1 part, Madder RT 1/2 part
Logwood 2 parts, Osage Orange 1 part, Madder RT 1/2 part