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Yeah I’m not necessarily a monobath fan, but that’s just how these developers came together as the easiest way to throw ammonia into the mix.

John I don’t know if you’re on facebook, but if so this is an ongoing active topic of conversation in Dry Plate Photographers group.

If you had any thoughts, Lee Lira would love to hear...

Just ordered some whole plate sleeves. Thanks for the heads-up.

By the way, Priority Shipping is currently the cheapest way to ship parcels, at least for small businesses. 1st Class parcel post...

Hypering gas was an 8% hydrogen / 92% nitrogen mix. I used to do this for astrophotography using Tech Pan.

Here is a page on Jerry Lodriguss’ website discussing the details of hypering film. ...

I use a heavy duty guillotine style paper cutter. It cuts very similar to cutting heavy card stock.

Nice results!

-Jason

The method OP is referring to is the combination of using the dry plates and a developer which causes (as far as I can tell) dichroic fog of a type resulting in an off-white toned silver grain.
...

I ran out so I had to pull the ad until I get another shipment in.

He’s a great guy.. doing some awesome stuff!

It’s adhesive failure in the doublet, ie “balsam separation” although this lens is too new to have used balsam. This is what failure of modern adhesive looks like. I’d bet it wasn’t originally...

On a limited basis, Randy, while I work on refining the results. I’ve started listing in the Experimental section of the store when I coat enough to box up, so that folks can experiment with them...

I’ve been enjoying experimenting with dry plate ambrotypes: Black glass coated with my ASA 25 emulsion and developed to a positive.

For film, Adox CHS II 100 and the CatLabs 80 speed stuff are...

As Havoc notes, f/# values change by the area size. As such, the numbers change by the square root if 2.

As an optical engineer who has tested non-uniformity of imaging systems many times over my career, my first and primary suspect is the actual setup of the test described: I.e. Sheets of regular...

The ChromaGraphica double dry plate holders are NOT 3D printed. They are modern, injection molded assemblies, designed by photographers who are also engineering professionals.

Will fit 4” x 5”...

Makes sense.. essentially glass enjoys a nice cleaning in a mildly alkaline solution, which is what you’ll get with that.

I don’t know any optical shops which use that. Too time-consuming for production to “touch” each lens. For large quantity optics, glass washing machines using distilled water and a purpose-made...

Drew, I did some homework before recommending storage methods for dry plates (my recommendations are never arbitrary. :) ). The dry plate boxes and envelopes sold through Gaylord (and a couple other...

Did you try picking it up *completely off the countertop* and rocking it around? This and 500ml of developer works for me with B&W, C-41, E-6, etc. It’s the same equipment as yours, so it’s fair...

As an optical engineer who is familiar with the hazards of lasers, I would advise *against* viewing the focused image of a laser spot with the type of magnification used for viewing the ground glass....

Jim Noel is spot on. Theoretically, filters should contribute no optical power and therefore would not affect the image. In the real world, consumer-grade filters do have an impact... not focus per...

Yes, actually, because you cannot ignore alignment errors. Perfect alignment only exists on paper. Real, manufactured lenses are not ideal and have associated tolerances they have to meet to ensure...

Stopped down, I agree that there may be benefit, knowing what I know of stray light and ghosting. So yes, you could be on to something.

At very small apertures light rays are intersecting...

Hey Tim,

I’m 85% sure that Eastman set the standard dimensions for holders in large part by buying up other companies and making them convert to the Kodak standard sizing. If standard 5x7 holder...

Hey Steven,

It’s due to the newly formed airgap. The index difference between adhesive and glass is not significant enough to form visible Newton rings.

-Jason

Yes, they are wavelength-dependent geometric effects.

Sphero-chromatism: focus vs wavelength
Lateral color: Distortion vs wavelength

Fun fact: Focus is considered an aberration... the...

All of the basic, third order Seidel aberrations can and have been corrected completely. The Cooke Triplet does that. Higher order / residual aberrations, however...

Drew... LOL. I just.... What you saw was the effect of turbulence, integrated over the exposure time of your camera and the response time of your eye. :D

Diffractive effects over a mountain...

Because it is not a geometric effect.

Agree on all accounts..though the concoction is straight from Norland and my experience in the optical shop doing this is a bit different than yours (if you do the math, you find it’s only 0.78%...

Obviously works in a pinch, but a more robust method:

100 parts Methylene chloride. 15 parts methanol, and 3 parts ammonia (26% conc) is a gentler / better solvent for removing balsam and uv...

I successfully completed the ChromaGraphica Kickstarter campaign, getting everybody’s holders out to them and resolving the occasional issue.

Got the rest of the production shipped here and...

Kent, that looks like a Chicago bolt or Chicago screw. Measure ID of the hole and length you need, and look up a replacement part in McMaster Carr.

https://www.mcmaster.com/chicago-screws/
...

It actually means correction at three wavelengths, so a bit more general than that. At least that’s what lens designers understand it as. I can’t speak for marketing misinterpretation.


Drew,...

I can help you with that, assuming the lens can be easily removed from the cell. Shoot me a message. Happy Thanksgiving!

-Jason

Aspherical surfaces and ED glass are tools in the optical design toolbox, helping with certain aspects and having pros/cons but are not magical “solve-all” solutions.

Apochromatic refers to the...

I was talking to Tim once about this topic and I think he has determined that development issues in the tank have consistently come from too gentle of agitation.

Personally I pick the tank up and...

ChromaGraphica Double Dry Plate holders now available for sale through the online shop under Accessories at www.pictoriographica.com

These are post-Kickstarter campaign holders, built here in...

No worries, Paul...didn’t take it as such. I was sharing in frustration that I can’t push the prices down much. My gial has always been to make plate shooting affordable. I could get the price...

You're talking about Coma, an off-axis aberration. The aberration illustrated in that link is coma as well.

Spherical aberration is an on-axis aberration, due to the lens not being the ideal...