Red Fabric Woes

With Christmas right around the corner, I thought I would gather all of my red/cream vintage blocks to see what I could make from them.   I have seven 9 patch blocks and 2 larger ones that I thought could somehow be worked into a lap quilt.  

First of all, though, I wanted to see if the red fabrics were colorfast.

I began by pressing them with the iron set on "cotton".  Unfortunately, like other vintage red fabrics that I've tried to use, the color transferred to my ironing board cover/press cloth.  

I really wanted to work with these blocks, so I decided to try to set the color.  A strong vinegar/cold water solution was the first thing I tried. The blocks were soaked in that for several hours.  While soaking, some color came out in the water, but did not transfer to the cream fabrics.  The vinegar solution was rinsed from the blocks under clear, cold water.  I noticed that the water was still running red/pink.  

What next?  I made a strong solution of salt/cold water.  Again, the blocks were soaked in this for several hours.  When rinsed, the water seemed clearer, so the blocks were laid out flat on a towel to dry.

After all of the soaking and drying, the blocks were a bit wrinkled.  So they were pressed with the iron set on "cotton".   To my dismay, still a bit of color transferred to my white press cloth.  

I am really curious as to why the red fabrics do this.  I have tried to research the fabric dying techniques of the last quarter of the 19th century by consulting one of the books in my "library"--Clues in the Calico.  I could find nothing there.  I tried an online search for an answer.  No luck, but someone else had had the same issue several years ago and her query had not been answered.  I even sent emails to vintage fabric experts, Xenia Cord and Barbara Brackman .  Xenia replied that she has had the same thing happen, and is pretty sure that synthetic dyes were used for red fabrics in that time period.  She didn't give any solutions to the problem, however. 

I decided to just put the blocks back in my stash for now.  I did not want to spend time on a project that may give me problems in the end because of red fabric "run".  

It didn't take me long to begin another vintage block project--it's in the works!