Getting darker indigo color
  • This weekend I tried out the Indigo dye kit with my kids. I was trying to dye a jacket a very dark indigo (see Blue Blue Japan for an idea of what I was looking for) but I only got to a very strong dark blue, not even to navy much less the blue / black I was hoping for. I dipped and oxidized it probably 6 times and it stopped getting darker after about 3.

    I was wondering if anyone has any experience getting darker colors out of the indigo dye kit? I was thinking of getting 2 kits next time and using both of them in a 4 gallon vat. I also read about using Retayne to set the dye and keep it from washing out. Another suggestion I saw was using salt and / or vinegar in the rinse?

    Finally, an idea I had was that if oxygen is oxidizing the indigo to an insoluble form in the fabric, could a rinse in an oxiclean or peroxide solution oxidize any remaining un-oxidized dye and, if it also had vinegar to neutralize the soda ash could prevent any of it from dissolving out.

    Just some thoughts I had, but I'd appreciate anyone's real-life experience making this work.
  • Hi Grendel,

    Because I know our kits can give one very, very dark indigo (almost black) I've got a couple of questions.
    Is the jacket you are dyeing 100% natural fiber? Is it silk? Is it a 'natural' silk like Noil?
    What color was your dye bath when you started dyeing? Greeny yellow or yellowy green is what you are looking for.
    And last, but not least, if you still have the Indigo box would you please provide the batch number from that? It is a stamped number or a batch sticker near the UPC code.

  • It's 100% cotton and I was getting the same result with cotton t-shirts and multiple dips. The dye bath was a yellow green with an oily indigo flower on top as I'd seen described.

    The batch number is 40003 with a date of 06-02-14.

    Any thoughts on what I should be doing post-dip to maximize indigo retention? Seems like a rinse in a mildly acidic bath would make sure the indigo isn't soluble any more, and an oxidizer like peroxide would make sure all of the indigo is oxidized.

    What I was doing this time was dipping one or more times, letting it oxidize for 20+ minutes, then running them through the washer and dryer with detergent.
  • Hi Grendel,

    Your Indigo Kit is pretty much brand new so that's not an issue.
    One other thing I forgot to ask - how heavy is the fabric of your jacket.
    The reason I ask is that there is a possibility that there are simply no more 'receptor' sights for the dye to attached itself to. As you noticed with your tee shirts they would only go to a dark blue and no further - the blues shown in this photo are considered a nice deep blue (although I've seen deeper on heavier fabrics).
    To answer your questions regarding the use of vinegar - there is nothing that I know of that can be achieve by using a vinegar rinse after washing. There is some possibility that an oxidizing agent might make some difference, but again, that is not something I've heard of using.

  • Hi Annette,

    Thanks for the answers. I've ordered a couple more kits and I'm going to try some experiments. I'm going to try making a double-concentration batch. I'll update this thread with my results.

    The thinking behind the vinegar is to neutralize the base solution (from the soda ash) with an acid since the reduced environment (from the thiox) makes the indigo water soluble. The vinegar should make it precipitate and the peroxide should oxidize it back into the blue form.

    I'm going to try the normal process (dip then air oxidize for 20 minutes), vs. the normal process plus a rinse in the vinegar / peroxide, vs. going directly from the dip to the oxidizer, vs. letting the fabric oxidize over night. All of these will be followed by a hot wash with Woolite dark. I've got some flour sack kitchen towels from Target that are white and I'm going to cut one up into swatches so I know they're all the same fabric.
  • Hi Grendel,

    I love your scientific mind set! I look forward to hearing what you discover - I'm particularly curious about the peroxide/vinegar rinse and hope to do some of my own testing this weekend.