Has anyone built Gordon Hutchings' Zone Board?greenspun.com : LUSENET : Large format photography : One Thread
In his book The Book of Pyro, Gordon Hutchings describes a zone board which permits a full test of 10 zones with one exposure. It sounds intriguing and I'm in the process of building one. Has anyone out there built and used one? If so what is the experience with it?
-- Alan Shapiro (firstname.lastname@example.org), December 29, 2000
You might consider using a Kodak Color Seperation Guide and Gray Scale (Large) The Kodak catalog # is 152-7662.
-- Ellis Vener (email@example.com), December 29, 2000.
I regularly make "zone rulers" encompassing 7-11 zones as a calibration tool and check on development and exposure. I have come up with a way to do it in camera on two sheets of film with nothing more than a gray card or other suitably even target. If you're interested, let me know and I'll e-mail you a document. (Can't do it here, to many tables, etc.). Regards, ;^D)
-- Doremus Scudder (ScudderLandreth@compuserve.com), December 30, 2000.
For those who are interested, the following is a brief description of Hutchings' zone board:
Picture this. He has a board, about 6 inches wide by about 7 feet long, painted a flat grey. At one end he has a blue 500 watt daylight bulb enclosed in a canister (e.g. a very large coffee can, open at one end. I am using a new, empty, gallon paint can). The light shines down the length of the board. With room lights off, there is intense illumination near the light source and the illumination falls off as one moves down along the board.
Using a light meter he assigns zone values (using markers) which are high near the light source and then go down. In my experimentation so far I can achieve about 10 or 11 zones. The board is then photographed using the zone V exposure meter reading. For example, if the reading on the meter is EV 12 near the light source, mark that point on the board (at the side of the board) as, e.g., zone 10. Read down the board until the meter shows EV 11 - that will be zone 9, and so on down the board. Set the exposure meter with EV 7 opposite zone 5 and expose the film at the indicated exposure. You then have a negative that is quite dense near the light source and then becomes less dense as you move along the board. The markers indicate where the different zones are and you can then take densitometer readings at those points and you've got yourself a film curve!
I have simplified the whole thing and anyone interested is advised to read Hutchings' The Book of Pyro.
So far the problem I am having is that the top few zones (zones 10 to 8 or 7) are very close together on the board and the meter and densitometer readings have to be very careful to distinguish among them. This is using medium format film. It should be easier, at least to read the negative, on 4X5 film.
But note that one film exposure (one sheet or frame) gives you all the zones you could want for curve ploting.
-- Alan Shapiro (firstname.lastname@example.org), December 31, 2000.
If the problem you are having is that the high zones are placed close together, this is probably because the bulb is parallel to the board. Illumination falls off as the square of the distance and it is hardly surprising that the lower zones (further away from the light) are further apart than the higher zones (closer to the light). You should be able to increase the spread on the 'zone board' by moving the paint can containing the lamp so that it shines on the board at a slight angle instead of being almost parallel to it. However, that might reduce the total range of zones on the same length of the board also. Hope this helps. DJ
-- N Dhananjay (email@example.com), December 31, 2000.