DIY 31 Megapixel Enlarger

avandesande

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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
 

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albada

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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

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Brilliant!

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

avandesande said:
the contrast is a real bear but overall
Click to expand...

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?

albada said:
Is the LCD color or grayscale?
Click to expand...

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...
 
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avandesande

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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

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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
 
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avandesande

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The problem with tablets and displays are that they have separate RGB components and the G/R don't do much to expose. Without some way to blur it you cannot get a good black.
 
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avandesande

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The last month has been about hard lessons. I purchased a cheap laptop to use in the darkroom, and the intel integrated graphics burned out my driver board as it did not recognize correctly. So most of my time was spent waiting for new graphics card from aliexpress. I also ordered a true 8k 7680 × 4320 33mp lcd with matching driver. Since I didn't want to risk any more issues, I bought a refurbished office tower off ebay and installed a RADEON RX 6400 card. It is the least expensive card that supports hdmi 2.1. Since the dimensions were slightly different I needed to build a new lcd/negative carrier. It pretty much works the same as the other one but with higher resolution. I developed a curve for it over 9+ iterations. I've never done it before I think it wont be as painful next time.
This is for foma retrobrom grade 2 in dektol 2:1. I've attached some scans, the scanner is lousy the prints look much better but you can get the idea of tonality. The two portraits are from raw files downloaded at dpreview....

​

 

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MattKing

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Threads combined, because the titles were essentially the same.
 

bernard_L

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Congratulations for this daring, yet successful project.
Despite re-reading the thread so far, it is unclear to me whether the "lcd panel" you use comes with its own light source, or whether you just use the polarizer/liquid crystal as any other negative, with a light source (which?) above.
 
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avandesande

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The lcd has no light source, so conceptually it is just a glass negative (or positive). I've attached pictures of the screen on a light box.
You can use any light source you want, these were designed to work with high intensity UV source, so it might even be possible to do alt processes directly from this.
 

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avandesande

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Here is a 11x14 print on Ilford Warmtone, it looks great in person.
I'm not set up for 16x20 but hope to test it eventually.
 

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avandesande

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A quick update, I have been working on the software end of things and have many improvements. I changed the conversion algorithm and it is 100x faster. It can now create images that when displayed in sequence will allow for 10 and 12 bit (~4000) levels of grayscale. The exposure module steps through them automatically. The software works with a USB power strip to control the enlarger light source. The monitor is turned off so you initiate exposure with the space bar.
 

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smng

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Hi Aaron, Glad to have found you here. I've been trying to achieve this same thing independently and glad to find someone that this has worked for. I purchased a 4K (BOE 5.5 inch 4K 2160*3840 LCD Model Number:VS055QUB-NH1-DQP0) screen with the same controller board (Alibaba). I'm encountering a confusing issue where it connects with some PCs (doesn't work on Mac) but not others. As I am now in the process of buying a refurbished/2nd hand PC laptop to make this work I was wondering if you could offer any advice for specs to look out for. Grateful for any tips.
 

koraks

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Welcome to Photrio, @smng!

Hopefully @avandesande will reach out to you. He'll receive an alert of this post, so I expect he'll check up on it.

I've been toying with the idea of setting up something like this myself. It's tempting, for sure. Let me know about your progress and feel free to reach out at any time!
 
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avandesande

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Hi SMNG- your best bet would be a laptop with nvidia graphics card. The one that worked for me was a thinkpad t540p.
I would say though that a laptop is not all it is cracked up to be- there is no way to turn off the display and if you close it the adapter for the LCD turns off. I've thought about covering the screen with ruby lith but never got around to trying it. I just covered the lcd with heavy trash bag as a stopgap. The refurbished business PC I purchased came with mouse, keyboard and 19" monitor for 115$ and you can just turn off the monitor when you don't need it.
 

smng

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Thanks for being so generous with that info Aaron. Much appreciated. Good point re: laptop screen. I'm going to look into a few options and will let you know how I go.
 

smng

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Any particular specs on the business PC you can recommend?

In the thick of some research, so hope you don't mind the extra questions. Seems I'm going to have to buy before I try. Did your thinkpad t540p have a nvidia or just a standard intel graphics card?
 

nmp

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I tried to figure out in that thread....what exactly is being done? Is an LCD display being used as a negative inside an enlarger or is it the light source. Not much background info to explain it all.

:Niranjan.
 

nmp

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koraks said:
Yes, that's it. The LCD displays a digital image, a light source projects through it. The LCD sits where the negative usually is.
Click to expand...

Thanks.

So basically the LCD is transparent to the light shining - you load it with an image and use that as a negative. What will they think of next...

:Niranjan.
 

nmp

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koraks said:
Yes, that's the principle of an LCD. We usually see them with backlight of course, but this one is basically a 'bare' LCD.
Click to expand...

I know how LCDs work. I didn't realize the driving circuit in the back would be "transparent" - never dismantled one. Perhaps more like translucent. I guess if the lines are small enough, they would just become the "base fog" for the digital negative.

:Niranjan.
 

koraks

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nmp said:
I didn't realize the driving circuit in the back would be "transparent"
Click to expand...

Yeah, the conductors towards the edge of the glass are likely a few microns at most. Since they don't carry any power, they can be made very thin. Btw, this is also the case with the display you're looking at right now
 

nmp

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koraks said:
Yeah, the conductors towards the edge of the glass are likely a few microns at most. Since they don't carry any power, they can be made very thin. Btw, this is also the case with the display you're looking at right now
Click to expand...
Yeah...bunch of videos online on how to take it apart and make a transparent display out of it. I can see how it might be useful to make a alt contact print with a UV source.

:Niranjan.
 
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