Re: [pinhole-discussion] [pinhole-dicussion] reciprocal failure
- Original Message - From: karol dzikamal...@interia.pl i've got an Zero Image pinhole camera and i've got a question concerning sth called 'reciprocal failure'. In a instruction added to a camera it's written that it means that i need to multiply the speed by 2 when it's 1-2seconds, by 4 when it's 2-4...by 12 when it's more then 10 or sth like this. anyway it's written in a very simplified way so i'd like to know some details. the aperture in this camera is 138. Karl, Exposure is given by a pair of parameter, they are: Time and Aperture, there is a reciprocal relationship between them. That means that if you increase one of the values by a factor X and decrease the other by the same factor X, the exposure will be the same. An example: 20 times 40 is equal to 800, but if you halve 20 and double 40, their product will also give you the same result 10 times 80 equal 800. Another example: f/60 @ 1/200 secs = f/90 @ 1/100 secs. Unfortunately, when your exposure time gets (usually) bellow 1 sec or higher than (usually) 1/1000 sec, that reciprocity between Time and Aperture fails, hence Reciprocity Failure. The effect is that you will need to expose for longer than what the reciprocal relationship is telling you. Each film has its own characteristics, therefore, each film FAILS in a different way. Guillermo
Re: [pinhole-discussion] Waxing Paper+Brown Cyanotypes
Its a matter of density. Pictoria is supposed to be able to hold more ink without running - so it should be able to create a higher contrast negative than other transparency mediums. If the negatives made with a regular transparency work for what is being done fine, if more contrast is needed pictoria. If even more is needed then perhaps waxed paper. I do my cyanotypes by shooting ortho film in camera and developing in a low contrast developer. I make big negatives and contact print them. This works very well, and is fairly simple, now that I have a reasonably good developer. Gord On Thu, 21 Nov 2002 l...@aol.com wrote: Couldn't you just print the negative on transparency material, the stuff used for overhead projectors? Seem s doable, and muck easier than waxing paper. If you want the funky look maybe print through store bought wax paper. Just a thought. - Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca112 Science Place http://duke.usask.ca/~holtsgUniversity of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 -
Re: [pinhole-discussion] re; city location in photograph
Leonard is right on the money. The Hancock building's distinctive trusses criss-crossing make it very idenitifable. And this part of Chicago is referred to as the gold coast I beleive. Thom - Original Message - From: Leonard Peterson lrp...@hotmail.com To: pinhole-discussion@p at ??? Sent: Thursday, November 21, 2002 11:06 AM Subject: [pinhole-discussion] re; city location in photograph It's Chicago. The black building is the John Hancock, the street is Lake Shore Dr and the beach to the left but out of sight is Lake Michigan. The apartment it was taken from probably rents for a zillion dollars a month. VERY high rent area. _ Tired of spam? Get advanced junk mail protection with MSN 8. http://join.msn.com/?page=features/junkmail ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
[pinhole-discussion] Re: [pinhole-dicussion] Reciprocity Failure (was reciprocal failure)
--- karol dzikamal...@interia.pl wrote: hi i've got an Zero Image pinhole camera and i've got a question concerning sth called 'reciprocal failure'. In a instruction added to a camera it's written that it means that i need to multiply the speed by 2 when it's 1-2seconds, by 4 when it's 2-4...by 12 when it's more then 10 or sth like this. anyway it's written in a very simplified way so i'd like to know some details. the aperture in this camera is 138. Karol - What you are referring to is Reciprocity Failure. Film is designed to be exposed for a certain period of time, oftentimes 1/10,000 of a second through 1 second. When you go outside of this design, the film will not properly capture the image if exposed for this time period. You need to adjust your exposure to compensate for a time outside of the film's design. Different films have different requirements when referenced in this context, so it isn't as simple as just multiplying the exposure by two (for instance, Tri-X and TMX are dramatically different). Look at the reciprocity failure information on the sheet of paper that comes with the film you use, and adjust according to the directions there. If you do not have that paper, enter reciprocity failure and the film type into Google and find it there. Cheers - george = Handmade Photographic Images - http://GLSmyth.com DRiP Investing - http://DRiPInvesting.org __ Do you Yahoo!? Yahoo! Mail Plus Powerful. Affordable. Sign up now. http://mailplus.yahoo.com
[pinhole-discussion] [pinhole-dicussion] reciprocal failure
hi i've got an Zero Image pinhole camera and i've got a question concerning sth called 'reciprocal failure'. In a instruction added to a camera it's written that it means that i need to multiply the speed by 2 when it's 1-2seconds, by 4 when it's 2-4...by 12 when it's more then 10 or sth like this. anyway it's written in a very simplified way so i'd like to know some details. the aperture in this camera is 138. thanks. karl -- Portal INTERIA.PL zaprasza... http://link.interia.pl/f167c
