The color is evidently being held in suspension in the wash water and is 
being re-deposited. "Color catchers" are good for picking up loose dyes 
in the water, before they have a chance to stain white or light fabrics. 
There are a number of products on the market that do the same thing. One 
that I use when I can find it is called "Dye Magnet."

The key to preventing permanent staining is to not let the quilt dry 
when the dye is sitting "in the wrong place." It may take a number of 
rinses to stabilize the running dye. If it is a lousy dye job, the 
situation may never resolve itself. If this is that much of a problem to 
the quilter, she would also have dyes in the quilt that could migrate in 
humid weather, when the quilt is stored in less than ideal home conditions.

Hope my input helps.

Patricia Cummings, who is not a professional conservator, but who is a 
collector and quilter

Jan Vuori wrote:
>
> Hello,
>
> I am posting this on behalf of a quilter. The problem is random 
> bleeding of colour in some quilt blocks that she has already spent a 
> considerable amount of time working on. She prewashes her fabrics in 
> cold water with vinegar. This is followed by rinsing. If the colour 
> runs she continues rinsing until the water runs clear. She has used 
> this method for many years working with fabrics from a variety of 
> sources and has never before encountered problems with the dye 
> bleeding randomly afterwards.
>  
> In this instance she used "Easy On" spray starch on a few colours to 
> facilitate working with small pieces. Then she washed the quilt blocks 
> in cold water to remove the spray starch. Upon final drying some dye 
> bled from the cranberry and some similar colours but only in random 
> areas. There was no correlation with fabrics to which spray starch had 
> been applied and seemingly no correlation with any other factor (such 
> as thickness of fabric).
>
> She was able to remove  much of the dye bleed by further washing in 
> cold water but had to take apart some of the blocks to replace areas 
> that remained stained or to prevent further staining
>
> Does anyone have an explanation for the randomness?
>
> Any suggestions to prevent this from happening again?  
>
> Jan Vuori
> Senior Textile Conservator
> Canadian Conservation Institute
> 1030 Innes Road
> Ottawa Canada K1A 0M5
> tel:  613 998-3721
> fax: 613 998-4721
> www.cci-icc.gc.ca
>