Sunday, October 24, 2010

Sunday, October 17, 2010

More about Indigo

I had a great Study Session on Indigos at the AQSG meeting in Bloomington on Friday. We did discuss how to tell a resist from a discharge indigo from the top of the quilt. Kay Triplet, one of the class members, had some very good thoughts...a resist may show a little leaking of color into the design if the edge of the resist print is not as thick as the center portion. The discharge print may show the opposite--a little leaking of discharge (slightly lighter color) outward from the edge of the design--as the discharge paste may 'leak' beyond the edges of the design.

The other hot topic in the Indigo session was how to tell early from late Indigo prints. Sue Reich had a wonderful pieced quilt c. 1837 which was assorted indigos.  Generally I think of early Indigo patterns as being larger and fancier than those seen after the Economic Depression of 1893 when so many mills went out of business, used cheaper greige goods and went to smaller simpler designs.

Sue's quilt confirmed my theory.  Many of the Indigo printed patterns were large and complex although there were several patterns that were tight and neat--i.e. small rings. I did get some time after the Session to really look at the quilt and the Indigos ( Thank you Sue!)  and I also noticed that some of the larger designs were on more coarsely woven grounds.

So some possible clues to early (before the last decade of the 19th century) Indigo prints are resist printing ( discharge is after 1813..in England), coarsely woven grounds and large complex patterns.

One of the excellent papers presented was "Prussian Blue: Its Development as a Colorant and Use in Textiles" by Anita Loscalzo. I have several sample books with wonderful Prussian Blue examples.

I am working on my daughter's computer today--no scanner and no samples books. The next post will be from home and filled with visuals!

Sunday, October 10, 2010

Illumination

When you do a discharge indigo and use two different discharge pastes, one containing a chrome orange dye, you get an Illuminations. This style of printing is one of my favorites!



This is the back of the 3rd block. Note the areas of white and orange showing through.


Sunday, October 3, 2010

Resist vs Discharge

There are 2 ways to 'print' indigo. The earliest approach is to print a resist on the undyed cloth. The resist can be mechanical--flour, starch, clay, resin, or wax--or chemical--salts of copper, alum or zinc. The length of fabric is then processed in an indigo dye bath. The pattern printed resists the indigo dye. A rinse of warm weak sulfuric acid removes the wax or zinc salts and you have an off white design on an indigo ground. Wonderful! 

Early in the 19th century a second approach was developed--the discharge method. The fabric is first dyed indigo blue and then a discharge paste is printed on that fabric. The oxalic acid 'bleaches' out the pattern design. The look on the printed indigos is similar. I have had people tell me they could tell the difference. Alas, I was not able until recently. In March I purchased some quilt blocks from a Senior Citizen's Center in eastern Ohio. There was one group of 8-pointed stars dated c. 1825 which had several indigo prints.  The back of one was different from the others. I think you can see how deep blue the back of this indigo piece is. 

There were pieces in other blocks whose backs look like this. You can see a 'shadow' of the design on the back. I think now if I can see the back, I might be able to detect Resist vs Discharge.
I thought you would want the see the fronts of these two blocks!