I noticed that the color charts on Rit’s site have different formulas for different items (shirts, curtains etc.) and I can’t figure out if this is supposed to be based on the material of these items or their relative size. Should we treat BJDs as large clothing? Also, if anyone wants to dye something to match a yellowed head/body, Rit Dyemore Sandstone is your friend. All of the videos/prev examples I’ve seen produced a cool, slightly reddish tan but for me it was bright buttery popcorn yellow, even on fabric
I believe the dye formulas are based on the relative size of the thing being dyed- a t shirt takes less than curtains. Since the dye can be used on multiple materials types, it'd be more complicated to give a formula for every possible combination of fibers. As far what formula to use for dolls, it'd depend on the size you're dying, but generally using a more diluted dyebath for a doll seems to be good advice; it's easier to adjust things to be darker than to be lighter
RIT Dyes come in a few different formulas. In my personal experience (the Dezombification serum), powder fabric dye gave me a not-great result. You have to look closely at the doll to see it, but the dye did not take evenly, and there were splotchy spots. I did have rubbing alcohol and a melamine sponge (a Magic Eraser) on hand to remove the worst of the splotchiness, but I won't be using fabric dye again. Rit has a synthetic formula called Rit Dyemore that I intend to use on a vinyl doll next. I just... haven't done it yet. What I will say is that Rit has very specific instructions on their website for how to use their dye, and I have yet to see anyone follow them in any videos I've watched. Every time I turn on a YouTube "How to Dye Your Doll!" tutorial, the person in the video just dumps the whole bottle in, and that is NOT what Rit's website suggests. Every single video ends with the person giving shocked Pikachu face to the camera, and I shut off the video in frustration. You can view Rit's instructions here.
Funny you should mention the de-zombification serum because I did that on Mika a while ago with liquid Dyemore (very dilute mixture of Sandstone and Racing Red) and it turned out very well. If you want to try it on a vinyl doll be careful with the soaking time. It took around a minute or so for the resin parts of Mika to take on a nice pink but the head got to the same color within like 10 seconds. You can see that her arms and hands don't match her face perfectly but it's a subtle difference that isn't visible in all lighting.
She's gorgeous! And I appreciate the tip - I suspected as much (that vinyl absorbs dye faster than resin), because vinyl is more porous. Or at least it seems that way? I used the three-part serum, and I was absolutely delighted with the results. I recommend that tutorial to everyone. I deliberately left the doll parts in the bath a little longer to get a darker color, but after 30 seconds, I got a beautiful, Unoa fairy resin-like color from my butter-yellow Angel of Dream SD body (it was almost banana-yellow from age).