There used to be an article by Alex Timmerman on the internets somewhere in which he demonstrated that the exaggerated swirl you sometimes see in images made with a Petzval is the result of an incorrectly assembled lens. A properly assembled one won't have as much swirl. Would post a link but I can't find it.
"Never try to teach a pig to sing. It wastes your time and annoys the pig."
seezee at Mercury Photo Bureau
seezee on Flickr
seezee's day-job at Messenger Web Design
The center of the image circle on a Petzval lens is pretty darn sharp. They were meant to be. The swirl that so many like comes from using a lens designed for a smaller format than that being used. Though, for example, a 5x7 lens will illuminate an 8x10 ground glass, the area outside of the 5x7 frame will fall apart. At least this was how it was explained to me, and it makes sense. Personally, the swirl makes me slightly nauseous, but clearly I am in the minority
Echeveria by Pau Martín, on Flickr
My first successful plate. It is a 8x10 tintype, shot with a convertible Symmar 300 at 5.6.
Q.J. collodion with modified Osterman developer. My previous attempts suffered from a heavy fog,
which I attributed to a too active developer. I changed the amount of acetic acid from 4% to 6%.
Fixed with Ilford rapid fixer. Sandarac varnish.
In a friendly circle of collodist photographers, we recently discussed the durability of various collodions. It is a well-known fact that Lea 3 is in the first place in this area. I have been using this formula for decades, and it contains only cadmiate salts. Mathew Carey Lea (1823-1897) himself wrote that this formula has a long shelf life (up to several years), which he somehow did not specify more precisely. other literature, however, stated the value "within two years."
This topic started to interest me a long time ago, but only from 2017 I started to consciously postpone a smaller amount (250 ml) from each mixture for further "research". I now have the oldest collodion 4 years ago, mixed on February 5, 2017, which I successfully tested last time in the autumn of 2020. Last weekend I did a few ambrotypes, so it worked perfectly, without changing color, consistency and, of course, photographic properties. and I haven't said that my recipe is not the same as the original. instead of ether and ethanol I use the same amount of isopropyl.
I wonder when the breaking point will come. has anyone made you such attempts?
P.S .: I'm sorry for my bad English
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