Making —Pyrrole Red watercolour paint

Ingredients

Current procedure — last updated 30. August 2022

  1. Mix the watercolour paste
    1. Wear a mask. Go outdoors - this can be very messy.
      Pour the medium into the stainless steel container first.
    2. Measure out the powdered pigment.
      Add about a third of it to the Blender Ball, and then top off with about 250ml of medium.
      Seal it up and shake back and forth 60 times.
      Repeat twice more, and then pour in the remaining medium and shake to roughly rinse.
    3. Start dispersing, using a dispersion disc in a drill press.
    4. Cover the bowl while dispersing to limit the dust.
  2. Mill the paste
    1. Set both rollers to 6mil.
    2. Prepare a large bowl and a hopper to use. Find a stand to raise up the bowl to catch the paint to reduce splashing.
    3. Use a nail brush and water to clean the rollers at the end of the first runs.
    4. Put through the mill 8 times.
    5. Test for grind at the end of run #4, #6, and #8.
    6. At the start of run #7, add one drop of clove oil for 250ml of total medium (100ml mix = 4-5 drops) Add the oil to the paste on the slow rollers, rather than in a bowl on in the hopper.
  3. Package into pans
    1. Arrange the 350ish empty 2ml half-pans into rows on a cookie sheet
    2. Fill the pans to the top with a pipette set to 2.3ml
    3. Allow to dry, and then top off
    4. Allow to dry, and then package into wax paper bags

Drapak’s manufacturing notes

30. August 2022 - 1 batch of 75g pigment: 500ml medium
Pr254 powdered Pyrrole red pigment: 75 grams × $0.240/g = $17.98
Watercolour medium 500ml × $23.09/1000ml = $11.55
Number of pans filled 205 pans × $0.08/pan Cost of pans = $16.40
Total for materials = $45.93 Material cost/pan = $0.224
Time to mix 22 minutes
Time for pre-dispersion 30 minutes
Time to mill 180 minutes
Time to dispense 30 minutes
Total time 232 minutes
Number of runs 10
Final grind size 7-15µm
Time spent per pan 1.13 minutes × labour rate $0.445/min= $0.504
Total cost/pan = $0.728

This was an interesting pigment. It wet quite well, and did not make much mess. It might even be OK to mix indoors.

I did 10 runs on the mill, but I am not sure if the 9th and 10th runs truly helped.

The material was somewhat granular at first, and tended to block up the rollers during the first few runs. Adding a little water helped in the early runs.

Later on, it got very very smooth, and was a real joy to mill. It has an opacity that looks great on the machine.

Dispensing was still irritating. The pump works so much differently with paste than water. And it is still not pushing out things rapidly. It about an hour to dispense the paste. I may have to add an option to change the speed of dispensing in the menu. I am even wondering if I should shift back to the old stepper drive. It was loud but fast.

17-18. August 2022 - 2 batches of 150g pigment:1000ml medium
Pr122 powdered magenta pigment: 2 x 150 grams × $0.349/g = $104.70
Watercolour medium 1000ml × $23.09/1000ml = $46.18
Number of pans filled 700 pans × $0.08/pan Cost of pans = $56.00
Total for materials = $206.88 Material cost/pan = $0.2296
Time to mix 15 minutes
Time for pre-dispersion 30 minutes
Time to mill 345 minutes
Time to dispense 150 minutes
Total time 540 minutes
Final grind size 10-15µm
Time spent per pan 0.77 minutes × labour rate $0.445/min= $0.343
Total cost/pan = $0.573

This was much better than milling the violet!

I mixed the pigment in the shaker bottles. I measured out 75g of pigment and scooped it into the bottle. Then I added about 330ml of medium and shook for 45-60s. Then I repeated this, and rinsed the bottle with the remaining medium. Making a paper funnel to place inside the bottle to guide the pigment and hold down the dust might be nice.

The shaker bottles left quite a foamy mixture, so pre-dispersing on the drill press helped get a more homogenous mixture.

Milling was pretty straight forward. On the first batch, run #3 was very slow. This was because I had not been stirring the mix in the funnel and in the catch bowl in order to keep things consistent. On the second batch, I consistently mixed the batch in the hopper and the catch bowl and it went about 30min faster.

I added the clove oil earlier on the second run. This seemed to make a more consistent batch, but I woke up in the night with nasty allergies. Nasty!

Dispensing took a loooong time. As usual. I need to get that electronic dispenser going properly.

I should note that the magenta seemed to swell and take on water a little, a little like the yellow pigment. During the first batch, this slowed things down quite a bit. I added 125ml of water to the mix for the second batch, and this sped things up quite a bit.

It is interesting that the cost of the pigment is still less of a factor than the labour.

20. July 2022 — 3 cups total using 1:2 from Kama Dispersion
Pr122 dispersed magenta pigment: 250ml = $81.13
Watercolour medium 2 cups × $11.86/4 cups = $5.93
Number of pans filled 300 pans × $0.08/pan Cost of pans = $24.00
Total for materials = $111.06 Material cost/pan = $0.370
Time to mix 15 minutes
Time for pre-dispersion 0 minutes
Time to mill 105 minutes
Time to dispense 40 minutes
Total time 160 minutes
Final grind size 10-15µm
Time spent per pan 0.53 minutes × labour rate $0.445/min= $0.237
Total cost/pan = $0.607

I found a 250ml bottle of Kama Pigments magenta magenta Aqua Dispersion. I mixed it into 500ml of watercolour medium with a whisk.

The milling was pretty good. There was a small amount that made it through the rollers, but otherwise the settings seemed good. It could be worth seeing if the rollers could be a little tighter.

I made 8 runs through the mill.

After the fourth run, I tested the grind and found that it was already excellent.

Clean up was great, and dispensing went quickly. I used a pipette set to 2.2ml and the dispensing went fast!

As a postscript, as the mix dried in the pans, the amount magenta was less than expected. I recommend using a 1:1 mix of medium to pigment dispersion if I mix this from the dispersions in the future.

16. March 2022 — 3 cups total using 1:2 from Kama Dispersion

750mL of Magenta Pr122 ($6.06 of medium + $80.13 of dispersion) = $86.19/368 pans = $0.234 per pan

Well, this is embarrassing to admit, but I have been milling a different pigment than I normally use. I bought the magenta pigment recommended by handprint.org, Quinacridone Violet (PV19), instead of Quinacridone Magenta (PR122). I have been losing sleep and going crazy trying to get magenta out of violet! This was actually a relief, since I was quite upset to be unable to get magenta, and I was worried that the problem was my competence. I am still concerned that the pigment is somewhat granular, but further experiments will help with this. I started to dispense the violet into pans: it was so smooth and creamy in comparison to the pre-made dispersions I bought.

Speaking of which, I did find an older bottle of Kama magenta dispersion to use for next semester. I made a batch of medium to mix it with, and then poured it into pans. The magenta was a little bit lumpy compared to the creaminess of the violet I made, but it is simply a better colour. What a learning experience!

Note: this batch had to be made in a hurry and was not milled.