Longer Exposure Times?

[Nonnef]

Ran my first prints from my LittleRP today and they kept coming out under exposed.
I started with the recommended 3500ms/5000ms setting but kept having to bump them up to get anything to work. You can see the final print turned out good, but I'm sitting on 8500ms/9500ms to get it to that, which seems much higher than everything I'm reading. And it's still a bit under exposed.

The resin is the MakerJuice SF V2 (Deep Red) that came with the kit. And I have an Acer P1283 for a projector with DisplayMode:Bright, Brightness:50%, DynamiBlack:On, HDMIColorRange:FullRange.

Am I doing something wrong?

Other than being worried I have something set wrong, I'm rather blown away by how great this printer is.

[Scatterplot]

I have mine set to 8000 for the first few layers then 4000 after that.

[Nonnef]

Did you modify any settings on the projector? Like increase the brightness or anything?
Because you can see the first few prints on mine at those setting didn't remotely cure.

[Nonnef]

Increasing the brightness to 100% only gave me a solid block of resin. Even at 65% it turned most of the resin to a gummy mess.
Reset the projector to stock settings and still having the same problem. It's printing fine as long as I keep the exposure high. Currently at 9000ms/10000ms and that seems to be my thresh hold. Any lower and I get under cured resin.
So my prints are taking awhile.
Got some different resin I'll try to see if maybe that's just the problem.

[android78]

Just a thought. Since the resin will only really be cured with the blue wavelength of light, the other colours will do nothing except heat up the resin. I'm guessing the 'gummy mess' you describe is due to the resin heating too much, so wonder if you print with only the blue but at 100% brightness if this could provide better results.

[Nonnef]

Tried setting the image on the projector to blue as you suggested but having the same problem. Not sure it's the heat, but just that the black on the projected image is still bright enough to partly cure the resin when set at the higher brightness.
Did calibration size checks and to get things to scale I had to shrink the BuildSize down to X=54.25/Y=30.5 which is significantly smaller than the recommended specks.

Which leads me to think I have something physically built wrong?

The P1283 only has one mounting point, and the zoom is set to center, so not sure it's that.
Do I have the spacers wrong perhaps? I didn't use any of the clear orange spacers when I installed the projector. Only the washer and the 3d printed red spacer. Would raising the projector those few MM change things that much?

[Scatterplot]

As long as you're focused right the zoom and spacers shouldn't matter. Are you sure you're focused on the build surface?

[Nonnef]

Pretty sure I am? The prints themselves are coming out great, just felt like the exposure time was higher than normal. But in looking over some other peoples experiences I guess it's only slightly higher (9000/10000).
Ran some tests with MakerJuice G+ instead of SF and the times dropped all the way down to 1000/2000. So I think everything that had me worried was just the resin I was using. =)

[goopyplastic]

the P1283 in my testing may output about 30% less UV than the P1500/H6510/X1240 so higher cure times would be in line with that.

[Nonnef]

Glad to know it wasn't anything wrong then. =)