Home-darkroom silver-gelatin prints from digital images

Started Apr 24, 2016 | Discussions thread
ZorSy Veteran Member • Posts: 3,486
Re: Home-darkroom silver-gelatin prints from digital images

tim baker wrote:

A regular computer screen was used for the negative image, having a vertical resolution of about 900 dpi. Resolution of the first 4x5 test prints was about 260 dpi, and looked shockingly good, considering. That primitive, essentially free, rig could have served for making small print forever.

Hmm, the average monitor these days is 1920x1080 pixels across 24"- give or take , the vertical RESOLUTION is slightly less than 100dpi (dots/per inch), not 900 dpi.

I've made several versions of the "camera" used to expose the print. Some surprisingly simple, cheap, and easy to make. The version I presently use projects the image to a horizontal 11x14 four-blade easel.

So, for printing 11x14 max, which would be almost 1:1 ratio to a FHD monitor, you would be having that 100dpi on the paper. Reducing the size, you would gain the dpi equivalent. But OK, you keep getting there.

But how good is the print? It's superior to a 35mm film/enlarger print in one way, equal in another: It's superior because its tone curve can be fine tuned in Photoshop as film's never could, the look of the print perfected as not possible with film. It's equal in real-life sharpness because even though a negative has greater potential resolution an enlarger-made print's resolution falls far short of that. The 5k screen is not being enlarged, it's being reduced, with essentially lossless resolution via a process lens and 8x10 "camera". The image on an 8x10 print with a half-inch border, for example, has been reduced from the screen's 13" 2880 vertical resolution to 411dpi on the print. In short, the 8x10s I'm getting with this system are superior to those gotten via film/enlarger during my long film-shooting pro career, 11x14s abut as good, and 16x20 in some cases.

That is mathematically speaking much better scenario. The only concern here is the bit-depth of the screen itself because it ultimately determines the dynamic range. Yes, I know you would say you can HDR/tonemap the image on the screen yet it is not equal to how film handles highlights/shadows (and gelatin paper reflects it on print).

But apart from such details, the main plusses here are being able to make real prints again, prints that look and feel like real prints, made with your own hands, with any type paper you wish, to any size and shape you wish, fine-tuning the look as you wish, having perfect prints in your hands minutes after shooting, prints that can outlast present sad fade-destined alternatives by generations.

A 4k screen, already owned by many and purchasable for $500 and up, can be used for an econo version of this setup. An 8x10 with a 1/2" border = 308dpi. A rare film-era print netted out that sharp. My favorite print type is the matted look, effected by wide white borders. 1 1/2 inch borders on an 8x10 = a 432 dpi image. That's sharp enough to cut your fingers.

Interesting idea, in particular if one is retired! I would agree that no printing technology of today (without post-finish) has the feel, depth and richness of stainless steel drum 'baked' glossy paper backed gelatin. The only downside is space, time and even money (if one has to start from scratch).

At some point I was thinking about the same whenever we watched family photos projected on HD projector (my largest ever home printed BW photo was 120x235 cm , this screen is 3m+ wide...). Then - I can print 13x19 on my dye sub, which is 'true' 300dpi (no dithering) and secondly (if I ever need larger), the local Officeworks will print poster for $25, hardly worth bother. Yet, I'm not retired, so you never know.

Keep up the good work. And hope the UHD/4K affordable projectors are not that far away...

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