Highest resolution
I've been playing around with the DLP projector setup with its 1080p resolution. I measured the smallest features I've printed to be around 0.25 mm. Its small but not that small. I wonder what else could be done to get better resolution. Probably adding an aperture.
It's a reasonable resolution since I don't have any way to really adjust the resolution visibly.
At 1080p, and a size of 8x10", what is the pixel size? Answer What is video resolution? 1080p - Wikipedia What is 1080p Resolution and The Difference between 4K and 1080p A Complete List of Video Resolutions and their Pixel Size
To calculate the pixel size for a 1080p resolution on an 8x10" display, we need to determine the pixel density and then convert it to pixel size.
Now, we need to calculate the diagonal resolution: Diagonal resolution = √(1920² + 1080²) ≈ 2203.39 pixels
The diagonal size of the display is: √(8² + 10²) ≈ 12.81 inches
Using the pixel size formula
Therefore, the pixel size for a 1080p resolution on an 8x10" display is approximately 0.147 mm.
So at 0.25mm I'm not actually far from the max.
Today I put together a rough focusing idea. First I got an old fluorescent blue sharpie and I dissolved the ink cartridge in IPA. Then I made a CMC mix and coated a paper with the fluorescent mix. Next I bought a really inexpensive Chinese filter on eBay "Various sizes ZB2 BG3 UV IR Dual-band 380nm Pass Filter Violet Glass". Using my super photonics engineering power I deduced that this filter would cut off all visible light except for deep blue and then allow UV to pass relatively freely. Having those two things I made a CMC cyanotype today that was the sharpest thing I ever printed so far and indeed the CMC formula allows for the printing of fine lines almost as small as the full resolution of my DLP projector. I will try this at lower scale to see if the details become finer.