I have a Mamiya Universal Polaroid setup (3x4, not 4x5) that I might think about trading, but I am ignorant as to Pentax's digital offerings. Does the K20D take old manual K mount lenses? I sometimes want a digital with more resolution than my Canon 10D.
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(Thanks for the picture compliment and welcome to APUG.)
Originally Posted by davidst
I have read claims that some toners will blacken brass. I didn't get very far trying to do that with Kodak selenium and brown toners, but maybe there are concentration issues. I had an ancient sample here of a liquid for blackening aluminum that worked fairly well on the brass shim stock I used on my SQ-Hole camera. I've wondered if gun bluing liquid might work, I think it just needs to be some smelly sulfur compound with the right acidity.
I don't actually punch the pinhole, I raise a pimple, then sand with fine wet-or-dry sandpaper. Doing that, the initial color of the stock doesn't help.
Originally Posted by davidst
Any blueing (or blackening), either chemical or heat treatment, is limited to the outer few microns. So yes, the inside would still be silver. If you use the "heat it up and quench in oil" method, you'd want to use a thin oil - Whale oil used to be preferred, but nowadays, perhaps a 3-in-1 would be easier to obtain. Be warned, the vapours will be highly flamable, so do it outside.
Originally Posted by paul_c5x4
What an active forum! Great hearing so many diverse views, and beaut ideas right across the spectrum. I just love people who THINK, so many of the flock don't. Thanks for your support since I joined only a couple of days ago.
The blackening by chemicals has given me an idea. I've still got some sheet sterling silver left over from a bit of silversmithing I had fun with in the past...another "hobby" I must find time for again. So I can punch a fine hole, then heavily tarnish eg blacken the silver using what the trade calls "Liver of Salts" makes rotten egg gas H2S. Stinks but will turn the hole and the whole piece nice and black. Of course still hope the hole doesn't develop any gunk, as reaming to clean for perfect hole, will "resilver" the hole and cause flare.
I'll keep codging...There must be something rigid, that's black, which will take a pin punch, that's not metal...
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I don't actually punch the pinhole, I raise a pimple, then sand with fine wet-or-dry sandpaper.
Raising a pimple and sanding, is a great way to get a variable size hole, by the degree of sanding. It also would stretch the metal, making it thinner than the undeformed stock. The pinhole must be in very, very thin material. Otherwise the light train is like going down a tunnel. It must be thin so the light defracts immediately around the edges.
We are nearly there...
I have just measured my old hole... pinhole that is. It is 0.4mm (1/64" for you non metric types), and at 120mm from the film plane it is f200, and covered a 4x5 piece of 100iso film. I'd reckon 1/64th should be a relatively easy drill size to get, so can consider drilling through v. thin super black plastic sheet, when I find it.
The Holga landscape pinhole cameras have black plastic pinholes.
It's all about the hole Johnny9fingers, so I hope I haven't highjacked your post. Get your camera suitable for the film, but think about the hole. If youve got an old folder, just take the lens out and put a pinhole there, nice easy film transport already incorporated.
Thanks for the offer 2F/2F, but I just picked up a Mamiya Universal Press with the 127mm lens and a few boxes of the old Polaroid 655 (665?) pos/neg film. Now I have me eye set on a Konica Instant Press. And yes, the K20D will take the K mount lenses.
Originally Posted by 2F/2F
No worries DaveT, sometimes we find little nuggets of info we wouldn't normally get if the thread held firm to the topic. It's all good. Now that I have the Mamiya Universal I'm looking into the best ways to rig it for pinhole work. It seems it can be as simple as a hole in tin foil, to a precisely machined brass pinhole with mounted shutter. This is just too much fun........John
not sure about image transfer, but there is a dude in Spain that with the FP-100C part that you put in the trash? makes the negative of that actual picture to show up, ready to go into the enlarger. The method is simple, you use a brush and regular bleach and brush the dark side and the negative appears like magic. The bleach can only go into one side of the negative, I guess the non emulsion side, if it goes on the other side it destroys the image. After that you washed to get rid of the bleach. It only works with the Fuji.
Originally Posted by geoferrell
Do you have to do the bleach processing right away, or can you store a batch of them and do it later?
Originally Posted by jaimeb82