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densitometro
Problem darkroom: Philips and densitomentro timer. On timer okbut
densitometer do not understand where to place the cell that allows check the density of the film resulting in the determination of correct shutter speed (say, more or less correct). From the first test returns values crock I think too low (type 3 or 4 seconds of exposure) but I have not risked the Click on either test. These are the questions: - on paper multigrade the densitometer should be placed before orafter the filter between lens and paper? - the density has to be taken on the film reflected on the paper? I know that the shutter speed is subjective and can be creative but Ineeded a timer and I found bundled with exposure, so that ... Thanks for the answers ... John |
#2
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densitometro
On 2/25/2011 8:32 AM, Giovanni Fiorino wrote:
Problem darkroom: Philips and densitomentro timer. On timer okbut densitometer do not understand where to place the cell that allows check the density of the film resulting in the determination of correct shutter speed (say, more or less correct). From the first test returns values crock I think too low (type 3 or 4 seconds of exposure) but I have not risked the Click on either test. These are the questions: - on paper multigrade the densitometer should be placed before orafter the filter between lens and paper? - the density has to be taken on the film reflected on the paper? I know that the shutter speed is subjective and can be creative but Ineeded a timer and I found bundled with exposure, so that ... Thanks for the answers ... John Hi Giovanni, First place the cell so as to read the densest part of the film (i.e., get the lowest value reading from the densitometer). Second, adjust the densitometer dials so that that spot gives a zero reading. Now, find the least dense part of the film and take a reading (that gives you the dynamic range of the negative.) At this point, you need to prepare (or consult, if already prepared) a chart - crosstable really - showing filtration on the left side, type of multicontrast paper on top, and densitometer settings in the middle. Creation of such a chart takes trial and error, because each type of paper has different sensitivity. For fixed grade papers, a different chart is needed as filtration is irrelevant. To obtain the proper densitometer setting, expose the paper for a particular filtration until you find the correct exposure time. Then adjust the densitometer dials until they yield that time when read at the densest part of the negative. That is the setting to record for that paper at that filtration. Finally, once you have consulted your chart, dial in the filtration, set the densitometer settings, place the cell on the spot under the densest part of the film, and read the predicted time from the densitometer. -- Francis A. Miniter In dem Lande der Pygmäen gibt es keine Uniformen, weder Abzeichen, noch irgend welche Normen, Und Soldaten sind dort nicht zu sehen. Siegfried von Vegesack, "Es gibt keine Uniformen" from In dem Lande der Pygmäen |
#3
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densitometro
"Francis A. Miniter" wrote
At this point, you need to prepare a chart ... .... such as the paper speed charts available at http://www.darkroomautomation.com/support/index.htm -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
#4
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densitometro
On 2/25/2011 21:52 PM, Nicholas O. Lindan wrote:
"Francis A. wrote At this point, you need to prepare a chart ... ... such as the paper speed charts available at http://www.darkroomautomation.com/support/index.htm Very nice. -- Francis A. Miniter In dem Lande der Pygmäen gibt es keine Uniformen, weder Abzeichen, noch irgend welche Normen, Und Soldaten sind dort nicht zu sehen. Siegfried von Vegesack, "Es gibt keine Uniformen" from In dem Lande der Pygmäen |
#5
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densitometro
Thank you all!!
"Francis A. Miniter" ha scritto nel messaggio ... On 2/25/2011 21:52 PM, Nicholas O. Lindan wrote: "Francis A. wrote At this point, you need to prepare a chart ... ... such as the paper speed charts available at http://www.darkroomautomation.com/support/index.htm Very nice. -- Francis A. Miniter In dem Lande der Pygmäen gibt es keine Uniformen, weder Abzeichen, noch irgend welche Normen, Und Soldaten sind dort nicht zu sehen. Siegfried von Vegesack, "Es gibt keine Uniformen" from In dem Lande der Pygmäen |
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