[vGPU]

>You can’t take a small negative and project it onto the paper, as you do with an enlarger for silver gelatin prints.

Pretty much sums up the point. Using 8x10 or whatever size negatives when film rolls were coming about is a non-starter for the general public.

The cost seems very high as the other commenter has mentioned also. From a quick search purchasing a kit will give you a printing cost of ~$15/photo. This immediately relegates it to the realm of hobbyists with money. Canvas prints of that size may be a bit cheaper for someone seeking something that’s a bit more special than a regular photo.

[tambourine_man]

It's possible to print large negatives from digital files. The results are stunning if you manage to get the curve right.

I've done a few times, lots of trial and error and I never could get a curve that worked perfectly on multiple setups or even on multiple shots with the same setup. A bit of tweaking is required for every shot, in my experience.

It's just that the whole thing is slow, expensive and error prone in every step of the way. It's a labor of love and it shows.

[nkozyra]

> It's possible to print large negatives from digital files.

You can actually do it on your home laser printer, onto transparent sheets.

You can then go even easier and make salt prints (also uses silver) and the sun. They come out very interesting.

[EvanAnderson]

This sounds like a great use for the laser transparencies I bought at Goodwill having no particular use in mind. Thanks for the idea!

[frostburg]

If you're going to buy platinum / palladium reagents, which aren't cheap, I suggest printing the digital negative on Mitsubishi Pictorico OHP. Check which of the inks in your printing system is more opaque to UV to improve dynamic range.

Use the media that your already have to dial in your pre-processing to some extent.

[tambourine_man]

It depends on the resolution and shades of gray your home printer can output. It will work, of course, but you may be disappointed with the harshness.

Last time I printed on an Epson 9600 @1200dpi. It looked awesome.

Salt prints are great fun and have a distinct look. Very different from palladium and platinum.

[balou23]

I did not really understand this point.

>The first reason is linked to one of the drawbacks of platinum photography. Although the resulting images are far superior, platinum does not react as quickly to light as silver. This means that you can only make an image using the contact printing technique

Wouldn't that just mean you have to wait longer?

[seszett]

> Wouldn't that just mean you have to wait longer?

You would have to wait much longer with a standard enlarger, probably several days and that's without taking into account reciprocity failure. In practice, it just wouldn't work.

I haven't tried platinotype myself since platinium and paladium are so expensive, but I do print a lot of cyanotype which has a similarly low sensitivity and I built a UV enlarger for that, which works quite well with exposure times on the order of a few minutes for enlarging 35mm onto A5 paper.

It requires a 40W 365nm UV LED source though, cooling for the negative in order not to burn it, and a few other tricks to get it to work well.

[dietrichepp]

> Wouldn't that just mean you have to wait longer?

In theory, yes. The actual values may help. I’ve heard exposure times cited around eight minutes. That’s for contact printing using the sun as a source. I don’t know off-hand how much light an enlarger will deposit on paper, but it is a few orders of magnitude less than the sun. For the sake of estimating, let’s say 3 orders of magnitude.

This gives an exposure time of 5 days. Note that you’d want to make a test strip or two—someone who knows what they’re doing might want two test strips to dial in the exposure settings, at which point it takes you 15 days to make the first print (but then only 5 days for each additional print from the same negative).

[balou23]

Thanks, that explains it.

I guess good thing you can "cheat" nowadays with digital enlarging (in the case where you "just" want to have a long lasting picture. I have pictures of my great great grandparents, I don't trust that any of my digital pictures will last 4 generations)

[masfuerte]

You can buy 50,000 lumen lightbulbs nowadays which, from 1 metre away, are in the same ballpark as the sun.

[dietrichepp]

Do they produce enough UV to expose platinotype? Most of the modern lights you see are LEDs that produce mostly visible light.

You can get UV bulbs, but at this point in our scenario we’re modifying enlargers, and the enlarging lens may focus differently in the UV region from the visible region (something you’d have to check and compensate for). Normally you’d focus an enlarger visually, perhaps with a grain focuser—maybe at this point you’d be focusing manually with the grain focuser in the visible region and then making some calculated adjustment for UV. Or you’d be hunting down a lens which was designed to have the same focal length into the relevant part of the UV spectrum.

[seszett]

> Normally you’d focus an enlarger visually, perhaps with a grain focuser—maybe at this point you’d be focusing manually with the grain focuser in the visible region and then making some calculated adjustment for UV

Yes, I have some experience with this (see my other reply in this thread) and it's a real problem but there is an easy fix.

Instead of using a grain-focuser (which would also be dangerous for the eyes anyway, and good quality UV lights don't leak much into the visible) you use plain white paper, cheap paper that is treated with optical brighteners.

These brighteners glow in the UV to make the paper look whiter, which means that under your UV enlarger, they turn the projected UV into a visible image. You can then focus using a regular looking glass to look at the paper. And UV-blocking sunglasses (you can easily test if they actually block UV: the paper will not glow at all if UV-blocking glasses are in the way).

Some lenses are corrected for UV-Vis focus shift, but they are generally extremely expensive.

[davidjade]

This is exactly it. Platinum printing requires UV. All of the platinum printing darkroom setups I have seen all had large and powerful UV sources for contact printing.

[MobiusHorizons]

How hot are they? You don’t want to scorch anything.

[nyrikki]

Negatives are smaller than you typically want the final images to be, with contact printing you positive images would be the same size as the negative.

Printing for end user consumption almost always involved enlargement.

The cost, inconvenience, and increased light of large format cameras with silver based films made them unpopular too despite the reduction in quality.

Similar to the quality vs convenience tradeoff that results in people using cell phones as cameras.

[iNerdier]

It depends what you mean by longer. One thing not mentioned is that platinum prints expose under ultra violet light, light which doesn’t transmit as well through glass to begin with, coupled with several orders of magnitude less sensitivity than silver emulsions.

Rather than a few seconds you’d be waiting several days for a comparable exposure.

[skhr0680]

Contact printing means you have to press the negative against the paper

[paulmd]

You can laser print an image (any image!) onto a projector transparency (overhead sheet) and do a contact print that way. Then you take it out into the sun and use that to expose the paper. Contact prints require very little resolution so a laser print (or an inkjet print) is generally fine despite not being that high a PPI.

The "authentic" way would be to create an internegative with an enlarger. You might use reversal-processed B+W film for example (creating a B+W positive), or create an interpositive and then use that to create an internegative (more steps obviously). Either way it's true that the analog process is a bit of a pain, but modern "hybrid" workflows completely remove this.

It's not just platinum prints that have this problem btw. Cyanotype paper is also extremely slow, contact prints are almost always the strategy there too. Given how slow it is, and the particular range of UV-sensitivity it needs, it's difficult to do indoors actually, but fortunately the universe has seen fit to bless us with a large, powerful UV source overhead for around 12 hours per day.

Same for azo paper and some of the other silver papers even... the kodak "postcard cameras" using 122 rollfilm (not 120!) were usually contact-printed and the simplest answer was to do it outdoors. Slow paper is actually easier if you are working outdoors, because it gives a longer working time and exact light levels or split-second timing doesn't matter.

Chemistry was simply much slower in the early days, a "fast film" in the early days was like ISO 8 iirc, and paper was even slower, you had "fractional ISO" in many cases. And a "fast lens" was a rapid rectilinear at f/8. Today we just take it for granted that an exposure is a fraction of a second but that was not at all a common thing in the early days of photography.

The idea of modern cameras with backlit CMOS sensors shooting ISO 256,000 with a f/1.2 lens would have vaporized a medieval peasant instantly. /s

And the idea of internegatives/interpositives has pretty much faded over time too. But this used to be a much more normal part of darkroom work. When you hear the term "unsharp mask" used... that actually comes from the times when it would be a literal mask, an interpositive that you enlarged together with the negative to control edge sharpness.

But yes you are right that analog photography is a rich person's hobby these days... the prices are significantly higher than even when I was doing it 10-15 years ago (which was already into the digital era). Almost all of these processes run on silver or platinum or other organometallic chemistry (with a few exceptions like cyanotypes) and the "metallic" part of that chemistry has climbed hugely in price, on top of sales volumes collapsing. The precious metal prices are why photo stores/etc will often take exhausted fixer for free... there is a commercially significant amount of silver in that bottle, and it all came out of your film/paper!