DIY 31 Megapixel Enlarger

[avandesande]

This is something that I have been thinking about since 8k monitors came out and have been waiting the last several years for prices to come down but it hasn't come to pass. Recently I became aware that small very high resolution monochrome lcd are being used for 3d resin printing. It's an interesting process where the lcd masks the resin exposure to UV light. The 8k version has only been available in the last year.
I purchased a lcd/display driver on ebay. The grayscale values are stuffed into the RGB channel of a pixel allowing the 8k image to transfer over low power hdmi 2.0 connections so I wrote some software to convert the images to display properly.
The panel is mounted in 1/8" polycarbonate sheet to fit the enlarger head with some extra space to mount the driver. Tonight is the first night I've actually printed... the contrast is a real bear but overall I think the quality is great.
There are several different types of 8k lcd available, from 15" (diagonal) down to 7". I picked this one because I was sure the driver would work with the lcd (they are sold as a set). I hope this is of interest to some of you I would really like to see B+W paper survive. Also this would be a great way to make negatives for alternate processes.

--Aaron

 

[albada]

Nice work! A few questions: Is the LCD color or grayscale? Assuming grayscale, can each pixel have 2^8 or 2^24 shades of gray? It looks like you have an 8x10 adapter on the enlarger. I just calculated that the diagonal of the usual 4x5 stage of the Beseler 45M is 6.4-inch diagonal, so the 7" LCD would be suitable for that.

Also, I see that my Beseler 45M isn't the only one with corrosion on the chrome horizontal bars.

 

[koraks]

Brilliant!

@avandesande - how do you manage exposure timing and the issue of light from the laptop's screen?

the contrast is a real bear but overall

As in, surprisingly high, I assume? I imagine this LCD has some serious blocking power and it has to be 'toned down' quite a bit to get within a useful contrast range for the paper. I'm assuming you're using VC paper? What kind of grades did you print at? Does your light source offer VC filtering, or did you use any other kind of filters?

I imagine that bringing down the contrast of the LCD to adjust to the requirements of the paper comes at a bit-depth penalty - effectively you'd only be using part of the 8-bit tonal scale that's available - is this correct?

By the looks of it, these are 8x10 prints. Is it possible to see the individual pixels with the unaided eye, and with a loupe? At what print size does the pixel pattern become visible - if at all?

Is the LCD color or grayscale?

Given its intended application, I assume monochrome, but I have to admit my mind wandered into color direction immediately given what I've recently been learning about RA4 paper...

 

[avandesande]

It's a monochrome LCD. I've only just started printing with it, I am using the foma #2 bromide paper. I will post updates as I develop the correct curves and try it on larger formats than 8x10.

 

[redbandit]

There is data online of sorts about people using LCD/HDTV monitors for enlarging large prints...

they flip the image on the screen, turn it off, place the printing paper down on it, and turn the screen back on... turn off, and process.

Have seen a few discuss using a diffusion panel between the lcd panel and the enlarger paper... but alot of people have talked about making their own enlargers and using the plastic panel from the LCD tv as a diffuser panel in a typical diffusion style enlarger circa 1970