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Darkroom Automation Precision Enlarging Meter: New Product Announcement
Hot off the press:
The Darkroom Automation Precision Enlarging Meter Darkroom Automation's enlarging meter provides 0.01 stop resolution over a ten stop range, making it easy to hit highlights and shadows on the first print. Its exclusive Delta mode quickly determines paper grade, burn, and dodge exposures. Working as a system with the Darkroom Automation F-Stop timer, it can also be used with any analog or digital timer. Absolute factory calibration means all meters read the same -- great for large commercial and university darkrooms [or sharing data on the internet]. $79 + s/h. http://www.nolindan.com/da/index.htm -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
"Nicholas O. Lindan" wrote in message
nk.net... Hot off the press: The Darkroom Automation Precision Enlarging Meter Nicholas: What is Delta Mode, please? Seriously, I don't understand. Thanks, |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
Nicholas O. Lindan wrote: Hot off the press: The Darkroom Automation Precision Enlarging Meter I wonder if it might make a good easel densitometer? I've calibrated my EM-10 against a step wedge for use as one. I figure about .05 resolution. Not bad for $24.50. Dan |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
"j" wrote
"Nicholas O. Lindan" wrote. New product announcement: The Darkroom Automation Precision Enlarging Meter http://www.nolindan.com/da/index.htm Nicholas: What is Delta Mode, please? Seriously, I don't understand. Thanks, I guess I need to expand the web site a bit, (cough). == Controls == The meter has two momentary pushbuttons on the top surface. o The left button turns the meter on and off: Tapping it turns the meter on; Holding it down for a second turns the meter off. o The right button toggles the meter between normal mode and delta mode and when held down takes a reference reading for displaying the difference between two spots. The meter turns itself off if no button is pressed in 5 minutes. == Normal Mode == The meter 'wakes up' in normal mode and works like a digital spotmeter where the spot measured a spot on the enlarging meter. The number displayed shows the quantity of light in 1/100's of a stop. The 1/100's display eliminates rounding errors when several measurements are used to determine paper grade, base exposure and burn and dodge exposures. Normal Mode measurements determine the base exposure by measuring the shadows [low key], mid-tones [portraiture] or highlights [high key]. When used with the Darkroom Automation F-Stop timer a very simple relationship appears: ‘Paper Speed’ = Meter Reading + Timer Setting where Paper Speed is a constant. Given a paper and desired tone there is a number that is a product of time and light intensity that will produce that tone. Paper Speed is easily determined by making a test strip with no negative and adding the time of the strip showing the correct tone to the number shown on the Enlarging Meter. As we are working in stops for both time and light intensity simple addition is all that is needed for all exposure determinations. When Paper Speed is known the F-Stop timer setting is simply: Timer Setting = Paper Speed - Meter Reading. Any timer can be used with the meter: F-Stop charts and a spiral F-Stop scale for clock-faced timers come with the meter. Using charts and an ordinary timer is the most common method for ‘F-Stop printing,’ an F-Stop timer makes the work easier and more pleasant. == Delta Mode == The right button toggles the meter between Delta Mode and Normal Mode. Delta mode shows the light intensity difference between any two spots on the image. The meter is placed under the part of the image to be used as the ‘reference’ or ‘base’ and the delta button is held down for a second. The meter display changes to 0.00 and the meter now shows the difference in light intensity in stops. An ‘r’ or ‘-‘ shows in the display to indicate a delta reading. The reference reading is remembered when the meter is turned off. Use Delta Mode to: o Determine paper grade by measuring the intensity difference (‘delta’) between the shadows and the highlights or between the two most important tones in the image. o Make fine corrections after making a test print by measuring the difference between two spots in the image: a spot where the print has the tone you want and a spot that has the tone you want to correct. The delta reading is the adjustment to the F-Stop timer/print time. o Determine dodging and burning requirements. Several methods are possible but an example is: Measure the foreground highlights and the highlights in the clouds - the delta reading is the amount to burn in the sky. == Meter Calibration == The meter is calibrated so that full scale, 9.99, is approximately the amount of light needed to achieve full black in two seconds on Ilford MGIV. The other end of the scale, 0.00, is the amount of light needed to achieve full black in 2000 seconds – 33 minutes of exposure. All meters read the same under the same conditions. This allows data to be shared among photographers. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation http://www.nolindan.com/da/index.htm n o lindan at netcom dot com |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
wrote in message
oups.com... Nicholas O. Lindan wrote: The Darkroom Automation Precision Enlarging Meter http://www.nolindan.com/da/index.htm I wonder if it might make a good easel densitometer? A very good one, though an 'easel densitometer' won't read the same as an ANSI/ISO densitometer. On the other hand the 'density' it reads is the density that matters. Readings are very stable, all meters are calibrated, linearity is excellent. And it has a delta mode for reading intensity differences so if used as a densitometer it is easy to zero out film base+fog and enlarger height/f-stop. I've calibrated my EM-10 against a step wedge for use as one. And every EM-10 is different. A volume control potentiometer is used for the logarithm conversion: the graph of OD/Meter reading is not pretty. http://www.nolindan.com/em10graph001.jpg I figure about .05 resolution. ..05 OD - .15 stops The resolution depends on the density as the readout isn't linear. And you have to turn the lights on to read the dial. Not bad for $24.50. Dan For it's original purpose - to match light intensity when making Ilfochromes it is a great little gadget. As a densitometer, it can be done, and it is cheap, but it was never meant to be one. |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
Nicholas O. Lindan wrote:
wrote I've calibrated my EM-10 against a step wedge for use as one. And every EM-10 is different. A volume control potentiometer is used for the logarithm conversion: the graph of OD/Meter reading is not pretty. http://www.nolindan.com/em10graph001.jpg Not pretty. That's true. I've calibrated mine as with an 8x10 enlargement using the projection of the step wedge. I calibrated for 5 f stops; f8 - f32. At f8 the more dense steps and at f32 the less dense steps can be measured at a greater resolution. I figure about .05 resolution. .05 OD - .15 stops Exactly 1/6 stop. And you have to turn the lights on to read the dial. Even at f32 I can read the dial. Not bad for $24.50. For it's original purpose - to match light intensity when making Ilfochromes it is a great little gadget. As a densitometer, it can be done, and it is cheap, but it was never meant to be one. Ilfochromes? Any print. Dan |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
[Comparison of Ilford EM-10
http://www.bhphotovideo.com/bnh/cont...list&sku=24631 With the Darkroom Automation Precision Enlarging Meter: http://www.nolindan.com/da/em/em1003main.htm wrote Nicholas O. Lindan [from Darkroom Automation] wrote: And every EM-10 is different. A volume control potentiometer is used for the logarithm conversion: the graph of OD/Meter reading is not pretty. http://www.nolindan.com/em10graph001.jpg Not pretty. That's true. I've calibrated mine. Have to turn the lights on to read the dial Even at f32 I can read the dial. I can't. For it's original purpose - to match light intensity when making Ilfochromes it is a great little gadget. Ilfochromes? Any print. Dan Designed for Ilfochromes / Cibachromes ... color balance shifts if the exposure time changes; the goal is to make all prints at the same exposure time. The lens aperture is changed to keep the light on the easel constant. The 'calibration' value on the back is the dial setting for an 18% gray at 20 seconds [or thereabouts] with Ilfochrome. They _can_ indeed be used for any print but they were not designed for general purpose measurement of light. And that is why the ugly response curves weren't a design issue in the product: Ugly works; Ugly is cheap; Ugly is good. Some use the meter as they were intended - to keep exposure time constant - when printing black and white. For a 2 stop range, say 5.6-8-11 for a 50/2.8 El-Whatsitogon this works fine. For a four stop range, 5.6-8-11-16-22, it's ok: optical performance suffers a bit at f16/22 but print size is probably 3.5x5 and so the issue is moot. Early enlarging exposure meters had a piece of paper with an oil spot on it and a small light bulb behind the paper. When the light from the enlarger equaled the light from the light bulb the oil spot 'disappeared. Same technology in the year 1702 with parchment and a candle: hence the use of a 'foot-candle' as the standard unit of light, the candle was placed one foot behind the oil-spotted parchment. Back to the EM10: For general purpose use the ugly calibration curve means you have to calibrate each EM-10 with a step tablet and densitometer. Caveats with the EM-10: o At low light levels it can take 5 seconds for the meter to settle down due to the memory of the CdS cell. o The calibration curve drifts with temperature and humidity so the meter should be checked if darkroom conditions are other than normal. o The calibration curve drifts with time? I have one that behaves very differently than it did a year ago. This only happened in one sample and the problem may not be in the meter but in the measurement or record keeping. o The calibration drifts with use: the meter uses a plain-ole radio volume control. Expect the same problems with the meter as you have with some radios: you just _can't_ get the volume right anymore. If the meter is always futzed with at the same dial setting the carbon in the volume control at that location wears out. Ilford's instructions as printed in the B&H web site have the meter recalibrated every printing session: record what the meter reads that day with a standard negative/magnification/f-stop . They are a lot more stable than that, but calibration should be checked periodically. * * * The 'no enlarging meter/EM-10/DA meter' debate is an extension of the 'Throw Down Your Exposure Meter, Fools.' threads that pop up: Some [well, at least one] think 'Sunny-16' is the be-all of exposure. For others, what the camera picks when set to A or P is all that's needed. And some think if you really want to do it right a precision spot-meter is the way to go. Pays your money - makes your choice. A good exposure meter isn't needed to take a fine photograph/make a fine print but it does make the success rate higher, extend the envelope of what can be achieved and lessens the time and waste. One cheap meter and a box of paper in the waste basket costs the same as a good meter without using all that paper on test/oops/just a bit more|less prints. With a good meter [and a bit of practice] you don't get close, you nail it. No sights, plain sight or a scope: which do you want on your rifle? -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation http://www.nolindan.com/da/index.htm n o lindan at ix dot netcom dot com |
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Darkroom Automation Precision Enlarging Meter: New Product Announcement
On Tue, 05 Sep 2006 14:16:45 GMT, ...
carbon in the volume control wears out. --Nicholas O. Lindan September 5, 2006, from Lloyd Erlick, This explains everything! I'm indebted to you for this! The shock of recognition, no batteries needed ... regards, --le |
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