Printit 8.10
.1mm height
This is a wonderful color to play with for lighting purposes! I'm gonna start stocking up on this powder and it will most likely replace my love for black MG94.

-os3dp

Defining (2):
The size of the vessel can hinder your ability and technique for cleaning. The larger it is, the less likely you are of being able to successfully shaking soap+water and would need to wipe down with a rag and hot water. If fresh, this would work. If old, acetone and said rag would be mandatory.

The people who make the colors for me use kerosene to cleanup.  I have used that once.  I have usually been successful with using a "Dawn" type soap and sometimes a LOT of it but not always.

-os3dp

Extruder:
Mostly stock Filastruder v1.6 #1870 extruding vertically with full barrel header wrap insulation and a Filawinder. No melt filter for this test, though it is advised especially if your printer has a nozzle smaller than .6mm

Mixing:
Here I discussed mixing powder based colorants in a paint can with a printed mixing bit. I used this exact method for approximately 3 minutes then quickly stored the pellets in a ziplock bag with dessicate pouches for later extrusion.  In this test, I used 500g of virgin ABS MG94 and about 2g of colorant.

Extrusion:
Temp: 189c
Rate: 6-12 inch per minute
Average diameter:  1.74 +/- .02mm
I had a worn hopper which was sagging and did not allow a consistent feeding. I replaced the vertical clamp while extruding and I got roughly 9-12" per minute. For the sake of documentation, I felt the need for transparency.
I am blown away with the color consistency every time I try a new powder colorant even though I know what to expect.

Printer:
Printit Industries 8.10

Printing:
Temps: 245c/90c
Speed: 120mm/s
Layer Height: .3mm

I had the spiral vase profile temps a few degrees too high as I ended up with stringing, but it fed like butter seeing as it was only 2 days old when I printed with it. As for as printing performance, it was everything I have been spoiled to since reliably extruder with my Filastruder and Filawinder.

In certain lighting and angles the printed Indigo can look like a black or a very dark grey

Held up to a light source you can see the deep amount of blue and a hint of violet which creates indigo.

Comparison to available filament:
I first made indigo by blending masterbatch which I discussed here and it came out very dark and naturally had color banding like most filaments made at home with masterbatch. Printing the powder based was just as reliable with the powder based as with the masterbatch colorant, but far more consistent in terms of color. As far as I know, the only pre-made Indigo colored filament on the market is PLA from Europe which seems to be more blue.

Takeaway and comments:
This is a very dynamic color and would work best for odd-ball print jobs, quirky pleasure, or especially for projects related to lighting.
Simply put, if you have not tried powder colorants, due yourself a favor and ditch your masterbatch now. It was both a privilege, and easy to work with Jonathan on the 3 custom colors I requested. Indigo is such a seldom used color for pretty much anything, so it is really cool to get a reliable source. Purging the Indigo colorant takes much longer than other colors as I am currently finding out. It seems to take up to 150g to get a natural filament, so transitioning to the next "true color" will take some extra time and material, but this is where recycled pellets really help unless you have print jobs that do not mandate specific hues.

Cleaning after powder colorant use:
Purging the Filastruder:
Indigo took quite a long time to purge similar to the red powder colorant. To purge indigo from the Filastruder I used 100g of virgin MG94 pellets until it ran clean at 189c.

Cleaning the vessel:
Your cleaning process of the vessel will depend on a couple factors:
1) What material your vessel is.
2) How large it is.
3) What you use as a mixing bit.

Defining (1):
With a glass jar, hot water and a little soap goes a long way. Fill the vessel 1/3 of the way with water with about a quarter sized (24mm) drop of Dawn. Pour the soap before the water so the force louches, then shake violently.
With an empty paint can, a little hot water and a rag to wipe with is all that is needed. If you shake said paint can, you will get more powder distributed and have more cleanup. But with a mixing bit, the cleanup will be more defined.
Acetone can also be used, but this method would be far more preferred for the glass jar (shaking) method since the acetone may dissolve the vinyl lining of the paint can and potentially contaminate future batches.

Defining (2):
The size of the vessel can hinder your ability and technique for cleaning. The larger it is, the less likely you are of being able to successfully shaking soap+water and would need to wipe down with a rag and hot water. If fresh, this would work. If old, acetone and said rag would be mandatory.

Defining (3): 
The mixing bits sold at places like Home Depot are generally an ABS tip with an aluminum shaft and should not be cleaned with acetone. Either wipe down the bit with hot water and a tiny dab of soap immediately after mixing the colorant,  or let it sit and cure a while to let the colorant solidify on the tool, or transition to like colors . (i.e. red>orange>yellow / yellow>orange>red)
If you buy a metal bit or print one in PETG, PLA, or Nylon, acetone can work just fine fore a cleaner.