Home-darkroom silver-gelatin prints from digital images

Started Apr 24, 2016 | Discussions
Aaron801 Veteran Member • Posts: 6,368
Re: Home-darkroom silver-gelatin prints from digital images

SteveFranklin wrote:

Fair enough, you make good points - especially regarding the issue around negatives. That does actually make a massive difference Not having to dodge and burn or worry about scratches, still, you'd have to make test strips still right for test exposure.

Intersting.... I wonder though if with this sort of process you get get to a place with it that you know the exposure in the enlarger before hand. If everything is on the computer, you get get really precise readings of the tones and perhaps you then don't need to make a test strip each time.

I wish my children could experience the magic of watching that image appear in the developer. But not so much that I'd go back to it.
In terms of tonality, I have two Epson 4800, one of which is converted to wholly to black and white using John Cones Piezography inksets and software and believe me, they are imperceptible from traditional silver-halide prints.

I would have agreed with the OP about print quality not long ago... but recently I saw some B&W photos printed as some sort of computer output that were fantastic... and really looked to me like old school gelatin silver prints. I don't know much at all about the computer output end of it, but I know what a good B&W photographic print looks like and these were that...

Good luck on your quest though. photography is a big tent and I'm sure there are thousands of enthusiast, hipsters, craft brewers who would love to revive it.
One of my favourite photographers Rodney Smith still has all his work printed traditionally to his own exacting standard.

I'll have to look up this guy...

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my flickr:
www.flickr.com/photos/128435329@N08/

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technoid Senior Member • Posts: 2,250
Controlling non-linearities when going from digital to wet print

How is the density controlled? Is the inversion (digital negative) done in such a way as to incorporate the usual highlight and shadow compression to prevent clipping? Does it have a profile process similar to the ability to print a digital image in Perceptual, Relative, or Absolute all of which are applicable to Black and White, not just color.

OP tim baker Forum Member • Posts: 79
Re: Controlling non-linearities when going from digital to wet print

technoid:

Here's a sketch of the process. It seems complicated, but it only has to be done once, and it allows prints having richness and precision of tone exceeding the best possible with film/enlarger prints:
If starting from a color digital image, convert to b/w via your favorite method.
With Photoshop "curves" or similar, adjust the b/w image to your taste--make a best possible image, to your eyes.
Then "invert" the image, creating a screen negative.
To calibrate your particular monitor, enlarger, exposure and development process:
At a chosen f-stop, do an exposure test strip to determine exposure time needed to barely reach paper-black, the darkest the paper can be.
In "curves" raise the foot of the curve/line some amount (try 1/4 of the way up to start) and make a test print at that position, using your just-determined exposure time--use a full-scale image, with pure whites and blacks, and almost pure blacks and whites.
If near blacks go pure black on the test print, reduce exposure time a touch until almost-blacks stay almost black.
Examine the test print and see if the almost whites are too dark or too white. Adjust the foot of the curve a bit, to darken or lighten the whites tones as needed, such that almost-whites stay almost white. Two or three such adjustment tests will precisely nail the perfect foot position.
You can then use that position and exposure time for essentially all future prints when using that paper, developer, and f-stop.
Mid tones will likely be too dark at this point. Lower the center of the curve until mid tones print as they should. A print from this settings will look about perfect, pure whites, near whites, pure black and near blacks as they should be.
But mid whites and mid darks may rush too steeply or rise too slowly toward each extreme/have too much or too little local contrast. Adding an S shape to the curve, like the sensitivity curve of film, will let you precisely effect the tone distribution of your idealized screen positive image. A few trial and error test prints will be needed. That resulting S curve shape will be the generic curve you'll use for almost all of your future prints. You can make minor departures of S shape to adjust local contrasts for particular images if desired, control that not even Ansel Adams could achieve. Message me with your email address and I'll send example drawings of curves.

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Tim Baker

(unknown member) Senior Member • Posts: 1,578
Re: Home-darkroom silver-gelatin prints from digital images
1

fmian wrote:

I'm bowing out of this conversation if you can't see logic through the density of your ego.

...obviously for the better .

OP tim baker Forum Member • Posts: 79
Re: Home-darkroom silver-gelatin prints from digital images
3

Here's a link to photos of first, mid, and later incarnations of the enlarger/camera.

https://www.flickr.com/photos/140619371@N02/

First versions start at the bottom, but are a bit out of order. The early ones are primitive and crude, but it's good to see just how simple one can be and still yield top-grade prints.

Toward the top are the next and final versions, one quite large, a mirror projecting the image down to an 11x14 easel. Time-machine stuff for ex-film/darkroom people.

Near top is a batch of prints make with that rig and the 5k Imac screen; and at top is a 800dpi scan of a portion of one of them, a hint at just how sharp the prints are.

I'm struggling up the Flickr learning curve, so will post individual captions when able.

Hope to do a short real-time you-tube video of prepping an image, making the enlargement, and developing the print, with way primitive gear, to show how easy it would be for someone to begin making real prints from their digital photos.

Yell if you have questions, here or by private message.

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Tim Baker

Ron Poelman
Ron Poelman Veteran Member • Posts: 7,825
Excellent result, T.

Thanks for the photos, really interesting.

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Ron.
Volunteer, what could possibly go wrong ?

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SteveFranklin Junior Member • Posts: 43
Re: Home-darkroom silver-gelatin prints from digital images

That is actually really impressive...nice one...

jeffcpix Senior Member • Posts: 1,707
Re: Home-darkroom silver-gelatin prints from digital images

tim baker wrote:

Here's a link to photos of first, mid, and later incarnations of the enlarger/camera.

https://www.flickr.com/photos/140619371@N02/

You'd do better with a vertical stat camera. Many are thrown away -- or given away to whomever will cart them off. Depending on the model, you might be able to mount the monitor on top and project the image onto the copy stage.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR1.TRC0.A0.H0.Xprocess+camera.TRS0&_nkw=process+camera&_sacat=0

Vernon D Rainwater Forum Pro • Posts: 14,008
How to Post Pictures -- for Tim

tim baker wrote:

Tim Baker

The OP (Tim Baker) has asked (more than once) for help with how to post Pictures here in Dpreview Forums.  Perhaps one of the participating posters could provide this information for Him.

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Vernon...

OP tim baker Forum Member • Posts: 79
Re: How to Post Pictures -- for Tim

Vernon:

Thanks for that. I've posted pix on Flickr--link below--so possibly that's a good enough method.

Here's a link to photos of first, mid, and later incarnations of the enlarger/camera.

https://www.flickr.com/photos/140619371@N02/

First versions start at the bottom, but are a bit out of order. The early ones are primitive and crude, but it's good to see just how simple one can be and still yield top-grade prints.

Toward the top are the next and final versions, one quite large, a mirror projecting the image down to an 11x14 easel. Time-machine stuff for ex-film/darkroom people.

Near top is a batch of prints make with that rig and the 5k Imac screen; and at top is a 800dpi scan of a portion of one of them, a hint at just how sharp the prints are.

I'm struggling up the Flickr learning curve, so will post individual captions when able. Helpful hints appreciated.

Hope to do a short real-time you-tube video of prepping an image, making the enlargement, and developing the print, with way primitive developing gear, to show how easy it would be for someone to begin making real prints from their digital photos.

Yell if you have questions, here or by private message.

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Tim Baker

OP tim baker Forum Member • Posts: 79
Re: Home-darkroom silver-gelatin prints from digital images

Jeffcpic:

Stat or process cameras sure would work. That's a good suggestion. And like you say, they are as cheap as dirt, and there's still a few available. If someone is handy they could adapt a monitor to one and make prints. For most home darkrooms they may be too big and bulky. And they don't allow use of an easel--it's good to be able to change print size and shape and border size and shape at will, and move the easel around hunting for ideal framing, this conveniently done using a traditional bladed easel. But someone halfway clever could likely work around this to their satisfaction. I'd first make sure my $2,000 monitor would be happy resting belly up or belly down. For someone interested in making traditional prints from digital photos I'd recommend a particular toe-in-the water model: The red, box-like version second from the top in the linked photos. It's just 9.5"x11.5"x22", small enough to rest on a closet shelf or under a bed when not in use. It cost just $25 in materials and less than a day to make--plus the cost of the lens ($40 and up on ebay). Set the rig level and square to the monitor, the right distance away for the wanted image size, focus by sliding the ground glass--actually frosted Scotch tape on plastic. Set the paper in place... If anyone wants drawings I'll post them on Flickr.

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Tim Baker

OP tim baker Forum Member • Posts: 79
Re: How to Post Pictures -- for Tim

Captions finished. Start at the bottom photos; click on a photo and it will enlarge and the top of its caption will appear below.

https://www.flickr.com/photos/140619371@N02/

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Tim Baker

Laser JoJo New Member • Posts: 10
Re: How to Post Pictures -- for Tim

Tim, I find your project yery interesting.

All these discussions about resolution or what is better are worthless. There is no question of "sense". Do it or let it be! Don't discuss with people about pro or con. It will not work!

Important for you, me, and maybe many other people on earth is: Does it work? How are the results? How to use?

I print color images via a selfmade laser imager on traditional C-print paper with pretty nice results. I also tried projecting LCD-screens on paper, but this did not work for color. The lightsource of an LCD-screen is not good to match the spectral sensitivity of photographic paper. So I skipped this and did my laser scanning unit, which gives me more control.

The only problem with your process I see, is the loss of dynamic range with your setup procedure. If you try to adjust the density curve by changing black- or whitelevels of your digital image, you limit the number of possible greysteps. With a B/W image you only have 256 possible steps from white to black, which is not very much.

So the goal would be to cover the whole range of the paper from black to white without limiting the range of the digital image. Changing the shape of the curve slightly is not that critial. But setting the points for black and white is. As extreme example, if you increase the black +25% and lower the white -25% you cut 50% of your tonal range, giving you just 128 remaining grey steps in output.  The maximum number of greysteps a pixel can do is 256. All manipulations in endpoints  reduce the maximum number and limit the quality of your print.

This is not visible in many pictures, but in some cases, for example large areas of very light grey or very dark grey, you can see "steps".

Have you thought about using the contrast-behaviour of Multigrade paper by exposing images with different amount of green and blue?

Today, most B/W photographic papers are Multigrade, means that they are sensitive to green and blue light. The paper does not see the red part of your monitor screen.

You could increase your tonal range when using the natural behaviour of Multigrade paper. When exposing all with a simple B/W or grey image form the screen, you only use the "normal" contrast of the paper. By using the same image with more or less amount of blue or green, you can control contrast with the paper, without limiting dynamic range of your "digital negative".  Have you ever thought about this? So one way could be to expose an image using the maximum possible range of greysteps of your computer screen and adjust contrast via the paper. And instead of reducing the brightness of each the blue and green channel and reducing range again, do 2 different exposing times with 2 separate exposures green and blue. This is called "splitgrade" in analog darkroom.

I think this could give you a result much better than any inkjet print.

JoJo

OP tim baker Forum Member • Posts: 79
Re: How to Post Pictures -- for Tim

Jojo:

Thanks for your information and thought rich posting. One hope when going public with this system was to provoke this kind of discussion; it can only lead to improvements.

First, your self-made laser imager: unless it's under wraps for now, can you give details, such as its resolution, cost to put one together, mode of operation and such? Before going the 5k monitor route I'd hoped to use a laser projector, but even a 1080 resolution version cost about as much as the 5k imac computer and screen, and a coming 4k projector is expected to go for tens of thousands.

Re the gray step reduction issue: As far as you know, do adjusted images sent to commercial printers have the same problem?

Per my experience, Gray step reduction goes unnoticed unless fairly extreme. Anyone perceptive enough, and in the know enough to sense reduced steps would likely know to generate original full scale images with little or no need for black white adjustment. But argue back.

Your thoughts on addressing the problem with variable contrast papers: Useful in certain situations, and a good tool to have in your kit.

You make color prints at home from digital images? Possibly a rig like I'm using would work well for you. I'm not set up to print color, but if you'd like I'll make a b/w 8x10 of one of your images and send it to you. You can at least see the resolution and scale. I can't image why it wouldn't work for color as well a b/w. I'll message you my email address.

Tim
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The Davinator
The Davinator Forum Pro • Posts: 23,249
Re: Home-darkroom silver-gelatin prints from digital images
1

I found it easier doing a print on clear Epson material at whatever skze I wanted and made a silver gel contact print from that.  Way easier in my opinion.

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Laser JoJo New Member • Posts: 10
Re: Home-darkroom silver-gelatin prints from digital images

The Davinator wrote:

I found it easier doing a print on clear Epson material at whatever skze I wanted and made a silver gel contact print from that. Way easier in my opinion.

I never saw a contact print of a computer-printed negative. It may work, but there is also the cost of a good large format printer and the cost of the material. And for each correction, like contrast, you need to print a new negative, which costs again material.

If you have the full digital equipment and want to try a silver-print, it could be an option.

Tim, I don*t think, there is a resolution prolem with your prints. My laser imager has not more resolution than your 5K screen at the moment (4096 x 4096). And the laser spot is not a sharp square, it is unsharp (gaussian shape).

Color is difficult with LCD, because of the backlight. The backlight is not continous spectrum so the colors are not "pure" anough to expose the 3 layers of the paper. Color paper sees color different than the human eye (this is why color film negatives have this reddish look). The problem is not the size of the screen or the resolution. The problem is the background light. Professional imagers using LCDs, like the AGFA DLab or Kodak KIS and many others use a backlight from separate RGB-LEDs to adjust the amounts of red, green and blue backlight individually. Or they use a monochrome LCD and expose 3 separate channels R,G and B sequecially with individual backlight.

So once you want to use LCD for color, you should control the red, green and blue part of the backlight individually.

The Davinator
The Davinator Forum Pro • Posts: 23,249
Re: Home-darkroom silver-gelatin prints from digital images

Not may...it does work.  It has been used to a huge extend for alt processes like Gum Bichromate, Platinim/Palladium, etc.

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Don Forum Member • Posts: 83
Re: Home-darkroom silver-gelatin prints from digital images

Anyone here ever heard of a film recorder? A few years ago while doing lots of photo restoration we picked up a used 4x5 4k and 8k film recorder. Used this thing for 8 years till printers became archival and Kodak eliminated their good fiber paper. Today not sure you could find one altho still have mine. Polaroid actually made something that would record monitor resolution on a 4x5 sheet of film at 2k res.15 years ago.

For me closing that darkroom was the best thing that could happen even tho the negatives I wrote were perfect for enlarging all the other stuff in the darkroom were gladly stored.

OP tim baker Forum Member • Posts: 79
Re: Home-darkroom silver-gelatin prints from digital images

The Davinator:

"I found it easier..." You've tried this direct print process too? What setup did you use? I've tried both, and know a few photogs who use the printed negative route, continually hearing their moans of discontent, sparked by the multiple problems inherent with inkjet printing. Printed internegs are also an extra time-consuming step. And with the additional cost of the negative material, ink, and re-dos, the inkjet/negative option costs about three times what a direct print costs. This direct method is faster, cheaper and easier, with consistent and generally superior results. This is my baby though, so I'm likely biased, so argue back; I'll try to pry my mind open.

Tim

OP tim baker Forum Member • Posts: 79
Re: Home-darkroom silver-gelatin prints from digital images

Jojo:

"Color paper sees color different than the human eye..." -- " So once you want to use LCD for color, you should control the red, green and blue part of the backlight individually." Thanks. That's good to know.

Let's say, by the trial and error if no other way, you adjust screen color so that paper does see the image just as the eye does. Note that new color profile and activate it for each image when making color prints. This should allow color prints from a given screen then????

I only print b/w, but others using this rig might want to print color, and if the above fix would work the door would be open for them.

Possibly a dumb idea: Send me a sheet of the color paper you use. I'll cut it into 4 wallet-size portions and one 4x10. Using suggestions from your end, and research here, I'll make suspected screen color corrections. With the 4x10 I'll do a test strip to determine proper exposure and send that to you for processing. One portion of the strip will be exposed properly, and reveal if the color was adjusted properly. If not it will likely be close enough to suggest correction directions, to be applied to one of the wallet-size pieces. Likely before the wallets are used up the proper corrections will be nailed.

This might be more trouble than it's worth to you, and/or there might be an easier way. But yell if you want to give it a try. The b/w prints using this 5k monitor equal or better my typical past film/enlarger prints, so possibly the same would be true for color, enough so that it would be worth using.

Tim
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Tim Baker

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