Waterjet would not be realistic. Micro-laser is hypothetically possible, but would be a specialty service, probably pricey for a one-off. Condit offered a thick anti-Newton glass that was soft and drillable, making That's been unavailable for about 30 yrs now. Later AN glass is quite hard and brittle; so is coated optical glass. But coated glass doesn't do it for me; I still get rings.
Originally Posted by Drew Wiley
Drew, it's beyond realistic: it's real.
How can you say "not realistic"? You can even make a butterfly: https://www.youtube.com/watch?v=1TEhYy4AcfM
Why "not realistic"?
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Single thing is that you should use very flat glass, if not you get rings (those you mention) way easier. The glass used to make mirrors is very flat, but glass sold to make windows it may not be well flat.
Does it specify whether the bench/ wall models have a different (narrower) spacer casting between the neg stage and the column runner compared to the floor standing model?
I'll possibly ask Kienzle - they supply glass for the various Leitz Focomat II enlargers that use quite a thick piece of glass in their carriers. I'd be interested to know what the minimum quantity needed to get a suitable glass made would be - mainly because I suspect Condit made use of a suitable product already on the market rather than having the glass completely custom made.
Condit used an AN Belgian glass unavailable for a long time now. Isn't made, period. But if you can work with plain glass, ordinary 1/4" thick float glass works fine. But don't use anything tempered - too tricky to drill precisely. There are plenty of sources for flat optical glass if you want to go that route. As usual, Pere is making sheer guesses.
Drew, LOL
My dry plate coating glass platform was cut with a waterjet.
Minimum hole diameter with a waterjet is usually 1mm, with 0.1mm precision, registration precision is not influenced by that precision, this is not a guess, but a fact. Of course tempered glass is not suitable for cutting.
Last edited by Pere Casals; 17-Oct-2019 at 07:17.
Yes, you could dimensionally size glass using waterjet. But any glass shop anywhere can do the same thing with common equipment. I can do it in my personal shop with even tempered glass. I wouldn't trust just anyone to size optical glass. But you refute your own premise when you state 0.1mm hypothetical precision - that's like a shotgun where you need a sniper rifle; in other words, not nearly precise enough. Enlarge things a bit, and even unsharp masking misalignment becomes a visual distraction, not to mention the far more demanding applications for punch and register gear like color separations. And in sequential film operations, errors become cumulative.
Drew, register precision does not depend on the holes in the top glass, but on the holes in the film/mask, aren't you aware ?
Imagine that the holes in the top AN glass are 2mm larger than the pins, no problem !!! what keeps negative-mask alignment are the holes in the film/mask and the pins.
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Now let me explain how to DIY make a Top Quality ANR glass:
https://www.youtube.com/watch?v=XZ8FP0vJGMU
You need this (amazon):
You protect one side of the glass with any adhesive plastic, then you dilute the "etching cream" with plain water until it works at some 1/10 of the speed shown in the video, so it would take 100min instead 10min to do the same.
You submerge your glass in the soup until etching suits your taste. Done !!!
You may submerge as many glasses you want until you are tired...
Safety sheet says that it contains:
BARIUM SULFATE 0.0 - 6.0% 7727-43-7
SULFURIC ACID 0.0 - 9.0% 7664-93-91
SODIUM BIFLUORIDE 7.0 - 12.0% 1333-83-1
AMMONIUM BIFLUORIDE 21.0 - 27.0% 1341-49-7
What kind of gibberish is that, Pere? All the spacing has to precisely align regardless - punch, pin glass, pins on carrier, if a registered carrier is involved. Go tell an automotive machine shop that you don't care if the cylinder holes and the pistons are precisely matched or not. But you apparently thought I was talking about a top glass. NO. I recommend and use AN glass on BOTH sides of the carrier sandwich. Pin registered bottom glass was once a standard offering by Condit; and there was a logical reason for that. But Contact frame glass itself also needs to be drilled, and is ideally thick AN glass. But since that's no longer available, one can substitute a thin sheet of mylar, frosted both sides, between the slick frame glass and the negative in the contact frame. That trick obviously won't work when enlarging. I wonder how much of these "done" snake oil projects you've ever actually undertaken. Somewhere around zero, it seems. There's more to an effective Anti-Newton surface than simple etching. If you don't do it just right, you'll get a pattern showing on the mask or interneg or whatever. But you just posted a product designed for essentially frosting glass. All glass etching is based on hydrofluoric acid. Even if that worked, you'd have to polish it up quite a bit to make it fully clear again.
Drew, this is funny, lets go...
If the "registered bottom glass" moves this is irrelevant, the single thing that's important is that the negative and the mask are precisely aligned by the register, the position of the top and bottom glass is irrelevant if the negative/masks are kept aligned, weren't you aware?
Drew, don't get angry, man.
I'm working hard to control BW printing with digital CAST masking on LF negatives...
You have not participated in this thread: https://www.largeformatphotography.i...-curve-control
Also let me explain that this proofing tool https://www.largeformatphotography.i...ation-software is ready for action. By now I can predict the density of any spot in the sandwich and, since last weekend, also on the paper.
Now I'm working to sucesfully proof CAST masks, I advance at good pace in that.
This is not snake oil... "if" one day you try a CAST mask you will be aware.
Drew... look, I virtually bend the paper curve like I want...
Well, I'm glad you're having fun and finding a technique applicable to your own intentions. But you're into zonal masking, not precision image alignment by any means. The original question by Interneg was in reference to matched color separations; and all hell breaks loose if everything during that kind of procedure is not precisely aligned to begin with. And that's far easier to accomplish using classic punch and register film gear than via scan and post-alignment options, though I do know an electrical engineer who designed a pin-registered film recorder, and it takes real 8x10 film; but that's way beyond the skill level of most of us to make.
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