I haven’t tried the black resin, but that’s unlike anything I’ve seen with the clear. I tried out the version of your object Josh oriented and did the supports for. Surface quality is overall ok:
There is also an artifact I haven’t seen before, I’ll call it ‘chatter’ I guess, on the top edge here: 
There is also scalloping on the thin walls between supports on the platform side, but I don’t have a good picture.
Black isn’t supposed to be that flexible. Adding some clear would stiffen it up since clear cures easier. But you shouldn’t have to do that. If your clear was porous I would blame the laser for being weak. But in this case I think you just got an unlucky bottle of black resin.
Thanks for printing that!
Did any of the corners end up bent on yours? By bent, i mean two faces not meeting at 90 degrees and there being a slight slope to one of the faces?
The scalloping is due to cured resin layers being “stretched” between two supports during a peel. It’s down to flexibility of the resin (again). The “chatter” is due to peeling too - since layers are at an oblique angle to that edge and the cross-sections of that lip aren’t supported on both ends, they end up with tiny “rips” on the “free” end.
That chatter on the top of your picture is actually the base side of the print… I admit supports were scarce, but it shouldn’t have had a missing piece like that. It’s odd.
Just to clarify, that’s this edge:
I’ve come to realize that pretty much any straight section that’s not suspended between two supports (such as this one), no matter how short and no matter the relative orientation to peel side, will get distorted, or in case of tiny features like this, “abraded”. In my print it wasn’t nearly as bad as in Steve’s, but it was still pretty rough in the same spot. It probably depends on the state of PDMS.
Hmmm. Now i’m slightly worried that my laser might be miscalibrated (power-output-wise). The clear prints weren’t porous, but i did get a few (top, flat) surfaces that weren’t cured completely in the infill section. I attributed those to issues with suction (flat features and all), but now i’m not sure anymore.
Another interesting tidbit - black supports are 0.1mm thinner than clear supports (indicating end result of the black curing profile vs. the clear most definitely isn’t the same).
Yep, that’s the side nearest the base, but it is not facing the base. I don’t have an explanation for that failure.
As far as laser calibration, I really don’t think they individually calibrate the lasers, and definitely not individual resin settings. So I still guess resin issues. Was it shaken until your arm went numb? 
It doesn’t have to face the base. It’s not an overcure issue, it’s due to peel combined with a sharp (unsupported) corner. The corner gets pulled down during a peel (resin is too flexible - even clear - as mentioned before) and the very edge gets ripped slightly. Then the next layer builds atop a slightly damaged corner, accumulating error until you get a ragged edge. Corners formed by edges that are both somewhat aligned with the peeling direction exacerbate it - if at least one edge was perpendicular to the peel, it would’ve been fine (maybe with just a slightly more visible layering on the surface).
At least that’s my theory base on the previous few attempts - i’ve had that happen on multiple edges similar to this one, in multiple orientations where the edge (not necessarily this one) was matching these conditions.
Eyup. One other thing i’ve noticed about black is it’s surface tension is wildly different from clear’s. It forms “soap” bubbles between supports, for example, and tends to take ages to degas.
That’s… fairly crazy, then, as output power depends on input current and varies greatly between samples (it’s similar with LEDs - hence the need to bin them based on output at a fixed current).
I figured if it was curing power he would have had other issues during that large print, but maybe not.
EDIT: I’m confused Steve’s print for yours. Never-mind.
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