Archived posting to the Leica Users Group, 2000/09/24

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Subject: Re: [Leica] printing questions
From: "Clive Sanbrook" <clive.sanbrook@care4free.net>
Date: Sun, 24 Sep 2000 19:48:08 +0100
References: <B5F2C394.7672%howard.390@osu.edu><02ef01c02501$3089b4e0$62aa4f0c@worldnet.att.net> <v04011702b5f377f68f4d@[169.132.153.122]>

I don't have an F stop timer but do use the system with an ordinary timer -
which is remarkably easy - when setting the time just think in terms of a
progression doubling the time - i.e. 2, 4, 8, 16,32,64 seconds etc


If you begin from the test strip stage - expose the whole of the strip for 2
seconds at your chosen aperture, cover a small part of the sheet and give
another 2 seconds to the rest of the sheet, cover the original portion plus
another bit, give the rest of the sheet 4 seconds, cover a further section
of sheet and give the rest an 8 second  exposure, cover a bit more and give
a 16 second exposure.  cover a bit more and give the final section 32
seconds.

when processed the test strip will show bands for:

2 seconds
2+2 seconds         = 4 seconds = 1 stop extra
2+2+4 seconds     = 8 seconds  =  2 stops extra
2+2+4+8 seconds =16 seconds = 3 stops extra
2+2+4+8+16         = 32 seconds = 4 stops extra
2+2+4+8+16+32  = 64 seconds = 5 stops extra

I find this system much simpler when estimating  an exposure between two
steps,  as the difference can always be considered as quarter, half or three
quarters of the time between the two steps ( or smaller changes if you're
really picky) - and for each individual step these increments will have the
same effect i.e. just as stops do for the camera (Leica TTL of course!!)

If you compare this with exposure strips made using two second (or 5, or
whatever your choice is) the above system covers a much greater exposure
range  and each time step gives consistent density changes - rather than the
fixed time steps where each change in time gives a differing density change.


Sorry if that could be put more clearly - but try it next time you're in the
dark - Once you've adjusted your way of thinking there is no other way to do
it!!!


Regards


Clive Sanbrook

In reply to: Message from Martin Howard <howard.390@osu.edu> (Re: [Leica] Fw: Leica FS)
Message from "Sam Shoshan" <shoshan1@worldnet.att.net> ([Leica] Fw: Leica FS)
Message from Guy Bennett <guybnt@idt.net> ([Leica] printing questions)