Best method for fixing the dye and making it last?
I am seeking advice for the best method for fixing the dye and making it last for this dress that I ordered online. It is a handmade/hand-dyed dress that came with instructions for first-wash and subsequent washes; however, these instructions prompted some questions that I hope can be answered by those of you who have had great results.
Fabric: 100% long-staple cotton.
Dye used: Batik-dyed with plant-based colors.
Dye colors: Black and red.
Fixatives used: "As no industrial fixatives were used, colors may fade more easily."
Included instructions for first wash:
- Soak in salted cold water for 30 mins or use a color-fixing agent.
- Rinse lightly; some color runoff is normal.
- For better fixation, a second soak with salt and edible alum can help.
Included instructions for subsequent washes:
• Always wash separately from light colors.
• Hand wash or use a gentle machine cycle; avoid hard scrubbing.
I have essentially no experience with dyeing fabrics/fixing dye -- my only attempt was a comforter cover that I'd dyed with purple Rit dye. Of course, it came out splotchy. I don't recall what, if anything, I'd used for fixing the dye.
My Questions:
Is a salt soak the best method for fixing plant-based dye on cotton? If so, how much salt to use?
Would a color-fixing agent yield better results than salt? If so, which one to use?
Is there anything that I'd want to do -- or to avoid doing? (e.g., type of container for the soak, hard water, filtered water, distilled water)
Do I need to request more information from the creator of the dress? If so, what do I need to ask?
Thanks so much!
UPDATE 1:
I sent the manufacturer a message asking: 1. which color-fixing agent is recommended for the best retention of the dye; and 2. to tell me about the dye that was used.
Here is the response: "We use plant-based dyes, such as those derived from plant ash, which are not as colorfast as synthetic dyes. After receiving the dress, you can try following the color-fixing method suggested in the care tips."
So, I just sent a follow up message requesting if there is a specific brand/ingredient of color-fixing agent that is recommended.
UPDATE 2:
I am cross-posting this on r/naturaldyeing, though I'll also keep it in r/dyeing in case anyone here has a suggestion for the best fixative for this application. I'm not against using commercially-made fixatives, if applicable.
In the meantime, I've been researching fixatives on the internet. Most results have been either promotions of products or treatment of the fabric before/during the dyeing process.
The manufacturer had recommended edible alum as a fixative -- however, most results that I've found about alum indicate that it is used as a mordant/pre-treatment to dyeing.
Other sources claim that soda ash is used as a fixative for plant-based dyes on cotton fabric. Has anyone had good results with soda ash?
I'm not discounting dry cleaning, though that will be my last resort.