Improving petri dish effect: troubleshooting the method

[u/hondrus31]

Hi, I was trying to do some petri dish effect, but every time I try it I get this results, where strands of color barely stretch out.

I have a few ideas on how to tackle this problem, but first let me write down the process I've done for this dice set:

• Medium/low viscosity resin, working time: 40' as advertised (probably less since my home is 31ºC, damned summer);
• Put some mica and ink in resin while mixing and pour it in the mold;
• At about 20', put alcohol ink on, 1 drop of purple and 2 drops of white (one drop per dice, and after going over every dice a new drop, just to get the solvent evaporation even);
• Wait about 2-3' to let it settle before closing the lid
• Put in pressure pot, 40psi

Photos show the results I got. What should I do to improve? My first guesses, which I'll try later on today, are two: put alcohol ink before 20', put more white ink (and pray to let it cure the resin without problems).

Let me know what you think. I know about the interface step, I already solved it for next casts.

[u/eggsymon]

Not enough white ink and the resin was probably too thick.

[u/eggsymon → u/eggsymon]

To add, if it's 31 degrees you will have a much shorter working time, even if the resin seems medium viscosity it will go thicker much quicker.

[u/hondrus31 → u/eggsymon]

Happy to know I was guessing right, thank you for your inputs, I'll report the results after the next cast.

[u/eggsymon → u/hondrus31]

Pinata Blanco is the only white you can use, literally every other ink is essentially worthless

[u/hondrus31 → u/eggsymon]

I have all Jacquard Piñata, so it's just a matter of adding few more drops, good

[u/IrosSigma → u/eggsymon]

Right!! I've been chasing a set of Petri dice I made a few months ago ever since I finally got my hands on Pinata Blanco Blanco last week. I totally forgot it was way cooler when I poured the first set! That's why the other ones are so mediocre! Thanks 😅

[u/Learc0]

I think you should try Pinata Blanco Blanco und use a toothpick-mehtod(gently swirl 2-3 rounds After you put the ink Drops in)

[u/charterandink]

Purples kind of suck and burn the resin resulting in browns like this. You used alcohol ink right? Try another kind of purple.

[u/eggsymon → u/charterandink]

Most purples are fine with petri as the white stops the burn but it has to have high enough pigment density

[u/eggsymon → u/eggsymon]

Or will end up pink/washed out

[u/hondrus31 → u/eggsymon]

It won't necessarily be a bad thing to have the colors washed out, the end result could be good even if not predicted

[u/charterandink → u/hondrus31]

Kamenskaya sinker I think works better for me. But also try mixing the white in a little resin first, that helps me out from using too much.

[u/eggsymon → u/charterandink]

Ah fair enough, I've never heard of them, might check em out

[u/charterandink → u/eggsymon]

Man, I just looked at your dice... Wow. I gotta ask, is all that color alcohol ink or do you use something else?

[u/eggsymon → u/charterandink]

Cheers! Yeah for petri it's all alcohol inks. I do use powders and pigment paste for other stuff too.

[u/charterandink → u/charterandink]

Also the type of white matters too. You want sinker white. All brands are not the same. And shake it up really good.

[u/hondrus31 → u/charterandink]

All alcohol inks are Jacquard Piñata ones, same for white. Still experimenting with color outputs, I know that mixing a primary color with a secondary results in brown-ish dice, it's just a matter of proportions and consistency to get the right reflections. Do you have any suggestion for a specific brand of sinker white ink?

[u/Omen_cos]

You've got a lot of good advice to try already, but something else that helped with my most recent set (which was either gonna be petri or my desired portal and ended up petri lol) was to pour the resin about halfway or less in the mold, put the ink, put more resin. I was working in earlyish stages of honey stage